Micro 4/3rds Photography

Multi aspect sensor

2013-05-19T21:20:00.000+01:00

An important feature of the Panasonic GH1 and GH2 was the multi aspect, oversized sensor. They had sensors larger than that of the other Four Thirds sensor cameras. This allowed taking pictures in the aspect ratios 4:3, 3:2 and 16:9 with the same diagonal sensor length, and, hence, using the full image circle. This is in contrast with other Micro Four Thirds cameras, which apply sensor cropping at 3:2 and 16:9 aspect ratios.

When the Panasonic GH3 was launched late 2012, it was a big disappointment that it did not offer the multi aspect sensor feature of the two predecessors. But what does it mean?

The illustration below shows the two sensor sizes. The green rectangle is the standard Four Thirds sensor size, while the black corners outline the GH1 and GH2 sensor size. Since the GH3 has the standard sensor size, it crops to achieve 16:9 video recording (orange box). The GH1 and GH2, on the other hand could use the red rectangle for video recording, using the image circle more efficiently and also achieving a wider field of view given the same lens.

In video

In the illustration above, the GH3 video crop of the sensor (orange box) is 7.4% smaller than that of the GH1 and GH2 (red box), when measured by the diagonal. This means that when using one of the kit zoom lenses at the widest setting, 14mm, the diagonal field of view of the GH3 corresponds to 15mm in video mode. This was calculated as 14×(1+7.4%). So, as compared with the predecessor, the kit lenses will give you less wide angle when video recording.

What you can do, then, is to use a different lens. The Lumix X 12-35mm f/2.8 lens starts at 12mm, and hence, gives you a better wide angle during video. On the other hand, it has a more limited zoom range, stopping at 35mm, well before the typical portrait lens focal length of 42mm. It is an excellent lens, though, probably the best I have ever used.

Another option is the Olympus 12-50mm f/3.5-6.3 power zoom lens. While this lens generally gets mixed reviews, probably because of the limited maximum aperture, I think it is a very interesting lens. It is the only zoom lens to cover both the very wide and portrait lens focal length. On top of this, it also adds a macro mode and power zooming, as well as coming in a weather sealed constant length package. On the downside, though, it does not feature optical image stabilization, so using it for video recording on a Panasonic lens is going to be tough. Without a tripod or a good support, your videos risk being shaky.

It's good to keep in mind that the lack of a multi aspect sensor in the GH3 is nothing extraordinary. In fact, out of all video enabled consumer system cameras, the GH1 and GH2 were the only to feature the oversized multi aspect sensors. All other do not have this feature. On the other hand, most other video enabled system cameras have an APS-C sized 3:2 aspect sensor. When cropping such a sensor to 16:9 for video, this wastes a relatively smaller part of the sensor than when cropping a 4:3 sensor. Hence, the oversized sensor doesn't make that much sense with APS-C sensor. The illustration below shows this:

The Four Thirds sensor wastes 25% of the sensor area when cropping to video mode, and 7.4% of the image circle (diagonally). The APS-C, on the other hand, wastes only 16% of the sensor size, and 4.5% of the image circle. So the oversized sensor feature does not make as much sense with the more common APS-C sensor format.

Here is a side by side video showing the GH2 and GH3 in photo and video mode, both using the Lumix G 14mm f/2.5 pancake lens. It shows that when changing to video mode, the GH3 loses some field of view due to cropping the from the Four Thirds sized sensor:

In photography

If you like to take photos in the 4:3 aspect ratio, then there is no difference whatsoever between the GH2 and the GH3. The resolution is exactly the same.

However, the GH1 and GH2 had the option of using the 3:2 and 16:9 aspect ratios for photos as well, while still retaining the same diagonal field of view. If you intend to use the images in this format, then you would use the lens image circle more efficiently with these cameras, and the GH2 will give you better resolution to boot. Here is a comparison table:

Photo resolution	GH2	GH3
4:3	4608x3456 (16MP)	4608x3456 (16MP)
3:2	4752x3168 (15MP)	4608x3072 (14MP)
16:9	4976x2800 (14MP)	4608x2592 (11MP)

These differences are not that important, surely, but there is in fact a significant difference.

On the other hand, with a camera like the GH3, it is best to stick with the 4:3 format when photographing, and crop the image later, if needed. And that saves time and hassle while photographing, which is not the worst thing you could do. With the GH2, I would often change the aspect ratio when photographing something wide, giving me slightly better resolution. With the GH3, I just skip this part, which is easier anyway.

Conclusion

Losing the multi aspect sensor feature with the GH3 was a setback. However, the consequences are not that severe. You lose the very widest field of view in video mode. If you prefer using longer focal lengths, this might actually be an advantage.

Producing two sensor sizes was probably too costly for Panasonic. So I can understand their desire to standardize the sensor size from an economic point of view. The Panasonic G5 and Panasonic G6 cameras are said to have sensors based on that from the Panasonic GH2. However, they still do not have the multi aspect sensor feature.

In fact, Panasonic has done the same also in the compact camera market. Their LX3 and LX5 premium compact cameras featured a 1/1.63'' (8.07 x 5.56 mm) multi aspect sensor, larger than the typical 1/1.7'' sensor mostly found in these cameras. The newest Panasonic LX7 has a standard 1/1.7'' (7.44 x 5.58 mm) sensor, from Sony, incidentally. It still achieves the multi aspect feature by having a slightly smaller image circle. This also allows for the very impressive aperture rating of this camera, f/1.4-2.3.

I think losing the multi aspect rate sensor opens up the need for more wide zoom lenses. Only two lenses start at 12mm so far, the Lumix X 12-35mm f/2.8 and the Olympus 12-50mm f/3.5-6.3. The first of these is very good, but also very expensive, and a bit short. The second does not have OIS, and is hence not so useful for video on Panasonic cameras. With this in mind, I think that Panasonic should make a lens specified at something like 12-50mm f/2.8-4.5 with power zoom and OIS. That would be great for video use with the GH3.

GH3 video recording at high ISO

2013-05-09T22:07:00.000+01:00

The Panasonic GH3 can record video at a maximum of ISO 6400, up from ISO 3200 on the GH2. And the quality is quite good at ISO 6400, see an example comparison at ISO 200, 800, 3200 and 6400 here.

However, there is a rumour that the GH3 can record video at one stop more, ISO 12800, by dialling in +3 in exposure compensation. So, is this true? The quick answer is: Yes. But it's a somewhat strange process. I'll take a look here.

In A (aperture priority) mode

What's going on is this: In the Creative Movie mode, A exposure mode, you set the aperture and the ISO, and the camera sets the shutter speed. When setting the ISO to the max, and then dialling in a positive exposure compensation, nothing happens until you reach +2. Then, you get one more stop of gain (light) until you reach +3. So, it might seem like the camera gives you one more stop of ISO for free.

But what you don't see is the shutter speed. I think it is a big problem with the GH3 that it does not state the shutter speed during video recording, except in full manual M mode. This makes the camera much more difficult to use for video recording.

However, for the moment, you can trust me that the camera tries to give you a 180° shutter in video mode, meaning that the shutter is open half the time, or a shutter speed of 1/50s if you are using a 25 fps video mode. Except if you dial in +3 exposure compensation, then it reverts to a 360° shutter, one full stop more exposure. You see this as a significant gain in brightness, if you are video recording in a too dim environment.

This can be easily demonstrated. See the video below in the next section.

In S (shutter priority) mode

Set in a similar setting, where the lightning is not enough at ISO 6400, full aperture, and 1/25s (or 1/30s for NTSC camera), when dialling in +3 exposure compensation, you get around one more stop of brightness, as compared with the maximum exposure in M mode.

Hence, it is true to say that you effectively get around ISO 12800 by using the Creative Movie mode in S (shutter priority) mode and dialling in +3. This only makes sense when the lightning is very dim. Otherwise, you simply get a very overexposed scene, which is not what you want.

Here is a video demonstrating the features of the A and S modes:

Here are also comparisons of the exposure levels in the video. From left to right, we have the A mode, M mode and S mode. We see that when using the Aperture Priority (A) mode with no compensation, it corresponds to 1/50s (180° shutter). When dialling in +3, though, it corresponds to 1/25s exposure (360° shutter). In S mode, though, we get around one stop more gain at +3 exposure compensation, effectively around ISO 12800:

Conclusion

The GH3 behaviour is a bit strange here. In A mode, it runs a 180° shutter by default, i.e., one stop less than the maximum exposure. Only when you dial in +3, you get the full exposure, one stop more. Specifying a 360° shutter manually in M mode gives exactly the same exposure, i.e., there is no "magical" extra sensitivity when dialling in +3.

The feature might still be useful. If it is too dark for ISO 6400, and you want the camera to use a shutter speed as slow as possible, you can set the exposure compensation to +3. You might find that easier than switching to the M exposure mode, where you could do the same.

In S mode, though, you can also dial in +3, and get one extra stop of gain, but at the same shutter speed. This appears to be a way to get around ISO 12800 in video mode. Note that this only works when the lens aperture is set to the maximum. Otherwise, the camera would rather first increase the aperture to achieve the exposure compensation, rather than increase the ISO sensitivity.

Alternative solution

If you are stuck in ISO 6400, maximum shutter speed (1/25s in 25fps or 1/30s in 30fps, depending on PAL/NTSC region), and you still need more exposure, what can you do? There is a solution, actually. There is another, semi-hidden feature of the GH3. It can record video at even slower shutter speeds, to capture more light in each frame.

For example, I recorded a video at 1/13s shutter speed at a concert, since I needed one stop more brightness even at ISO 6400. Of course, this gives you only 13 unique frames per second, even if the video stream is still 25fps. And you get significantly more motion blur, since each exposure is slower.

Here is a short description of how it was done, and a comparison between 1/25s and 1/13s. You must set the mode dial to "Creative Movie" mode, and then set manual focus, and the "M" exposure mode. Then you can set slow shutter speeds, all the way down to 1/2s. At 1/2s shutter speed, you only get two unique frames per second, of course, so the video might not be very useful.

As you see, 1/13s gives more exposure, and better brightness in the dim lightning, but more motion blur.

Here you can see the full concert videos as well. The one recorded at 1/13s:

And the one recorded at 1/25s, which is dimmer, but has less motion blur:

Both these videos were recorded using the Samyang 7.5mm f/3.5 fisheye lens. The maximum aperture is only f/3.5, which is quite small for a prime lens. On the other hand, it is normal for a fisheye lens. If I had used a lens with a larger aperture, for example the Lumix G 20mm f/1.7 pancake lens, I would not have needed to use a slow shutter speed.

This feature was also available with the GH1 and GH2. I used it to record fireworks with the Samyang fisheye lens, at ISO 3200, f/3.5, 1/13s. Since the GH2 topped out at ISO 3200 in video mode, this was my only option to be able to capture it. Using the GH3, I would probably have used ISO 6400 and 1/25s exposure.

Product news

2013-05-04T09:32:00.002+01:00

Recently, we have seen some interesting product launches. Here are my opinions on some recent camera news:

Panasonic GF6

The GF1 was the fist "rangefinder style" Panasonic camera. It had enthusiast friendly features, like a PASM mode dial, thumb control dial, plenty of buttons, and the possibility to attach an external viewfinder. Later, though, Panasonic seem to have had a hard time deciding what to do with the GF series. The GF2 and GF3 were all about making the camera as small as possible, sacrificing the enthusiast features like wheels, buttons and the flash hotshoe. The GF5 is quite similar to the GF3, but adds, e.g., a more ergonomic grip.

In April 2013, Panasonic are making a bit of a U-turn with the GF6, bringing it closer to the enthusiast camera territory where the series where born. It is no longer about being as small as possible, but grows a little bit while adding a useful tiltable touch LCD screen, and sees the return of the top mode dial. It also has a metal surface top plate, which I think looks a bit cheesy, but I think many will love it.

It has sensibly shaped grip surfaces for the thumb (rear) and middle finger (front), making it much easier to hold than the smooth GF3.

The GF6 has a sensor inherited from the Panasonic GX1, which should give you a good image and video quality.

It comes with the new Lumix G 14-42mm f/3.5-5.6 II kit zoom lens, which is getting good reviews so far, being smaller and lighter than the predecessor.

Panasonic G6

The Panasonic G6 was announced in April 2013, almost half a year after the Panasonic GH3. Still, the GH3 is the better camera in virtually every way.

Not to say that the G6 is useless. Far from it. You may still be interested in the G6 for two reasons, mainly: It is smaller and lighter, and less expensive, while still packing most of the features of the Panasonic GH series.

It has a sensor from the GH2, however, with improved image processing. Sadly, it does not have the multi aspect sensor feature of the GH2. Even if the GH2 sensor on which the G6 is based is old, the updated processing adds a lot to the image quality. So you should still expect a good quality increase from the GH2.

In terms of video, it improves upon the GH2 features by adding 1080p resolution at 50/60fps (depending on PAL/NTSC), and also supports the extended tele conversion (ETC) mode.

When it comes to the design, it follows the GH3 trend by replacing chrome details with matte black. The overall shape bears a clear resemblance to the Leica R8 and R9, with elevated shoulders. While the camera is small, it has a generous grip, for better ergonomics.

This table sums up the size in comparison with the GH3:

Camera	GH3	G6
Width	133mm	122mm
Height	93mm	85mm
Depth	82mm	71mm
Weight	550g	390g

Another good news is that the G6 is the first Micro Four Thirds camera to feature "focus peaking". This feature highlights strong edges in the display, making it easier to focus manually, e.g., during video recording.

Panasonic Lumix G HD 14-140mm f/3.5-5.8

The superzoom lens Lumix G HD 14-140mm f/4-5.8 was the third zoom lens from Panasonic within this system. It was used as a kit lens for the Panasonic GH1, and then, later available on a stand alone basis. I was never entirely happy with this lens, as I think it is not very sharp in the wide and long end, and it's focus performance, despite the HD designation, is nothing special compared with cheaper lenses.

With this in mind, it makes me happy that Panasonic is now updating this lens. The new lens has better aperture specifications, about a third stop better in the wide end, and a sixth stop better in the long end.

The new lens is also smaller, and has a front lens thread of 58mm, rather than 67mm for the old lens. With the experience Panasonic has acquired since making the original lens, e.g., from making the excellent Lumix X 12-35mm f/2.8, I'm sure they can do a much better job this time. If you have the choice, I suggest getting the newer lens.

Some might miss a motorized zoom. After all, if this is really a video optimized lens, why is the zooming done with a manual, mechanical ring? Zooming smoothly during video is almost impossible with a manual zoom ring. Most likely, a motorized zoom would be too complicated for such a lens. The motor would need to be very powerful, to be able to extend the duo cam front part of the lens.

Also, I expect this lens to have a pretty well dampened zoom ring. The Lumix X 12-35mm f/2.8 sure does, making it possible to zoom quite smoothly even during video. Unlike the basic kit zooms, which have a quite sticky zoom ring.

Olympus E-P5

The camera was announced on May 10th, together with a new external electronic viewfinder, the VF-4.

Olympus E-P5, shown with the optional VF-4 viewfinder, and the Olympus 17mm f/1.8 lens

The camera inherits a lot of interesting and attractive features from the Olympus OM-D E-M5: It gets a tiltable LCD display, the new five axis image stabilization, now with automatic panning detection. Also, it gets dual control wheels near the shutter button. Using Panasonic lenses with OIS becomes easier, since the camera allows you to choose more easily if you want to use the in camera image stabilization (IBIS) or OIS.

As for the sensor, it is also the same as in the OM-D E-M5, which is good, since it has been hailed for the good image quality. You can take up to 9 frames per second in continuous shooting mode, although only 5 fps with autofocus enabled. For more easy manual focus with legacy lenses or during video capture, there is a "focus peaking" feature to assist you by highlighting sharp edges.

I think it is good that the flagship PEN style camera now comes with a tilting LCD screen. That is very useful. On the other hand, I think the lack of a built in viewfinder makes it less attractive. On the other hand, quite some people like using cameras without eye level viewfinders, so I guess it still makes sense from a market perspective. All in all, this is a modern camera with virtually all the features you could think of, in a somewhat classic retro design.

Blackmagic Pocket Cinema Camera

There is little doubt that, at the moment, the best Micro Four Thirds camera is the Panasonic GH3. However, the most interesting might very well be the odd Blackmagic Pocket Cinema Camera:

Not to say that everybody should rush out to buy this camera: Far from it. This is a very specialized camera. It does not take pictures, only video. And the video resolution is 1920x1080, nothing special at all.

However, since it is made for video, it has an imaging sensor optimized for video recording only, not photos. Hence, it is able to achieve much better video quality, especially in terms of dynamic range, handling of moire, and colours. It also supports higher bitrates, giving you less compressed video files.

Unlike the predecessor, the Blackmagic Cinema Camera, which also came with a Micro Four Thirds mount, the pocket version has an active mount. This is a very crucial difference. With a passive mount, i.e., no electronic communication, most Micro Four Thirds lenses are useless on the camera, as you are not able to change the focus or the aperture.

The active mount of the pocket version makes all Micro Four Thirds lenses usable, though. You can operate the aperture and the focus, and OIS even works on the lenses that have OIS built in.

The Panasonic GH3 handles autofocus during video capture surprisingly well, as I have demonstrated here. Even if the Blackmagic Pocket Cinema Camera features autofocus, you should not expect such a performance. Rather, you must probably rely on focusing manually during video capture, and there is a focus peaking mode to assist you.

On the negative side, the camera has a significantly smaller sensor that Four Thirds size. There is a crop factor of 2.88. This means that the Lumix G 14mm f/2.5 becomes a 40mm equivalent lens, i.e., a short normal lens. Finding a good wide angle lens might be difficult.

Also worth noting that the camera does not correct for geometric distortion, for the lenses that feature this. Quite many M4/3 lenses require software geometric distortion correction, and they will give you distortion issues on the Blackmagic camera.

This is a camera for video enthusiast, who want the best video quality in a compact and relatively ergonomic package.

After the release of the two Blackmagic Cinema cameras, Magic Lantern have announced that they will make available firmware upgrades for the Canon EOS 5D MkIII. The upgrades enables RAW video recording at 24fps, at 14 bits depth, suitable for movie makers. The firmware also adds other features like larger resolution videos, 2.5K, 3K, 3.6K and other sizes.

What's even more impressive, is that the features are expected to be ported to the Canon EOS 6D, Canon EOS 5D MkII and Canon EOS 600D cameras! This firmware development may well remove a significant part of the market for the Blackmagic Cinema cameras.

28mm APS-C compact cameras

Within the last months, we have seen two new cameras in the somewhat thinly populated class of large sensor compact cameras. This market segment has previously been pioneered by Sigma with their strange and quirky DP series. Fujifilm were the first to get a good impact here, with the retro design 35mm (equivalent) Fujifilm X100.

Nikon and Ricoh now want a place in this segment as well, with the Nikon Coolpix A and Ricoh GR:


Nikon Coolpix A	Ricoh GR

Both feature retractable lenses with a 28mm equivalent field of view, and an aperture of f/2.8. What's more, it is reasonable to believe that both feature the same APS-C sensor from Sony. The APS-C sized sensors are commonly used in consumer DSLR cameras.

The Ricoh camera is slightly wider, but slimmer and lower, and also lighter. They have similar features, and the choice largely comes down to what type of ergonomics you like. Beyond that, the Ricoh GR also packs built in ND-filter, which is useful for large aperture shooting outdoor in sunlight. It also comes with a significantly lower price tag. It appears that Nikon want to capitalize on their strong brand name by charging a premium price for their camera.

Given that one would often want a camera like this to be slim and fit in a pocket, I think the Ricoh version looks the most useful. The Ricoh also appears to have the upper hand in terms of optical performance, based on the tests I have seen so far.

Neither of the cameras have a tiltable LCD or the possibility to attach an external EVF, which is too bad, but hardly unexpected since they are intended to be compact and rigid.

Autofocus during video comparison, GH2 vs GH3

2013-04-28T21:51:00.001+01:00

When the Panasonic GH1 was announced in April 2009, it had a unique selling point: It was the first and only consumer system camera which could autofocus continuously while recording videos. Since this time, the competition has improved a lot, of course, and all mirrorless system cameras can autofocus while recording videos. But they use different technologies, and the performance varies.

The Panasonic GH3 was released with a claim to have the best AF performance of mirrorless cameras ever, as usual for a new premium mirrorless camera. And the AF performance for single still images is very impressive indeed. However, this doesn't really matter. All current Micro Four Thirds camera focus more than fast enough for static still images. Except possibly with the Lumix G 20mm f/1.7 pancake lens, due to its combination of a fast aperture and an old school focus construction.

What's still a challenge, though, is continuous autofocus during video recording, and focus tracking of moving subjects, in AF-C mode.

The Sony SLT cameras solve this by using a fixed translucent mirror, which means being able to use phase difference autofocus (PDAF) also during video recording. This system is able to track moving subjects very well during video, due to the genuine SLR PDAF technology. However, the cameras are not mirrorless, being DSLR systems with fixed mirrors, which means having larger camera bodies, and, usually, larger lenses as well.

The Nikon 1 system and Canon EOS M system solve this by having on-chip PDAF sensors, directly on the imaging sensor. With this technology, they can combine PDAF and CDAF, however, the real world benefits of this system are still undecided.

Panasonic and Olympus have so far used pure CDAF, with no specialized hardware to aid the focusing. They rather rely on image processing to speed up the autofocus. With the Panasonic GH3 being the most recent premium model, let's see if it actually does improve upon the predecessor GH2. To test the cameras head to head, I mounted both on a plank using Manfrotto Superclamps:

On both cameras, I used the Lumix G 14mm f/2.5 pancake lens. The lens focuses very quickly. Even with the same lenses, the GH2 has a slightly wider field of view in video mode, due to the multi aspect sensor feature, which the GH3 misses.

Here are the results in terms of autofocus performance during video recording:

As we see, the Panasonic GH3 performs much better than the GH2 in term of autofocus. Even with the same basic technology, the GH3 has a better image processing capability, which enables it to focus better while recording videos.

Notice that the GH2 needs to jog the focus back and forth to confirm the focus and settle. This is a typical sign of CDAF focus technology. The GH3, on the other hand, appears to nail the focus straight away, as if it was using PDAF. Which it doesn't.

I think it looks like the GH3 is a revolution when it comes to continuous AF during video for Micro Four Thirds. It may be the first camera to make AF during video truly possible.

And this does work well in real life situations. Here, I have recorded a concert using the Olympus 45mm f/1.8 at f/2, ISO 3200. The light was very dim, around EV2. The autofocus was left on during the video, and it generally keeps the image well in focus. In my experience, the GH2 would not have handled such a situation well:

Keep in mind that AF-C while photographing moving subjects is a totally different subject. I would expect the Panasonic GH3 to perform better here as well, as it is capable of AF sampling at up to 240fps with the most recent lenses, the Lumix X 12-35mm f/2.8 and Lumix X 35-100mm f/2.8. However, I have not tested this feature yet.

Panasonic GH3 review

2013-04-22T20:53:00.003+01:00

The Panasonic GH3 was released in December 2012, two years after the predecessor GH2. While the GH2 was an incremental improvement over the GH1, the GH3 is a completely new camera.

This is for better and for worse, of course. The camera has grown significantly in size over the GH2, but it also adds better ergonomics and more features. Whether this is good news for you, or bad news, depends on what you want from the camera. If you want a camera which has a good grip, and a good layout of buttons and control wheels, then the GH3 is for you.

On the other hand, if you came to the Micro Four Thirds system for the smallest camera with a good photography and video recording performance, then there are other cameras that may fit your needs better, e.g., the Panasonic G5 and G6 (announced April 2013) or the Olympus OM-D E-M5.

Panasonic GH2 (left) and GH3 (right)

Almost every aspect of the camera is improved, compared with the GH2. There are some exceptions to this, and let's look at them straight away: It no longer has an oversized multi aspect sensor, the EVF has different optics which is smaller, hence it is not as well suited for people who wear glasses. Also, some have reported bad sharpness and image smearing, although I have not seen this myself. There are also some features that are not as easily available through the Q menu or the function keys as before.

Beyond just improving upon the GH2, the GH3 also includes some fun new features, like Wifi and built in timelapse recording. It also has rotation sensors built in, meaning that it can support auto-rotating images that are not taken with OIS lenses (previous Panasonic cameras could not), and it can show water level type lines in the display, to help you keep the camera level.

Physical

The GH3 has a more hefty feel to it than the GH2. This is due to the increased weight, of course, but also due to other materials. The GH2 has a steel chassis with a plastic body around it. While I think this is a completely adequate construction for a small camera, others think that there should be more metal in a high end camera body. And the GH3 caters to these needs, as it adds a magnesium body construction.

Also, the control wheels and buttons feel higher quality than the GH2. When moving the wheels around, they have a more satisfying clicky feeling to them, indicating a durable premium construction.

While the GH2 has a lot of cheesy chrome details, the GH3 has changed these to matte black. This makes me quite happy, since I think the chrome shutter button, lens release button, and so on, were just stupid. This makes the GH3 look more professional.

Even if the camera is larger, it still fits inside the Lowepro Munich 100 camera bag, which I like to use when only bringing one lens.

In use

Compared with the GH2, the GH3 not only adds more control wheels and buttons, it also reorganizes them. If you are used to the GH2, you need to acquire new routines. But the changes are generally good. For example, previously, the AF-mode selector was on the left shoulder, while now it has been moved to the rear, operable with the right thumb, much easier to use.

Generally, the camera is very customizable. There are some odd and negative changes, though. With the GH2, the Creative Movie exposure mode (P, A, S, M) could be set by using the Q-menu. With the GH3, though, the only way to do this is to use the touch screen, as far as I can see, which is a bit awkward when using the EVF. It can also be done by digging fairly deep into the menu.

Panasonic GH3 (front, left) and GH2 (rear, right)

In general, the GH3 is a pleasure to use, with the larger grip, and the very customizable controls.

The GH2 had horribly slow buffer flush speeds. The GH3 improves upon this significantly, and this is no longer any issue. I haven't measured the speed of clearing the buffer, as I don't see this as any problem any more.

The GH3 also packs a bigger and more powerful battery, and can keep shooting longer before needing a recharge. Third party spare batteries are available cheaply, and are completely adequate.

On the GH2, the distance between the memory card door and the card itself was small, making it hard to wedge out the card. The GH3 memory card door is much better designed:

Panasonic GH3 (left) and GH2 (right)

Autofocus

Since about the second generation of MFT cameras, the still image autofocus performance has been more than fast enough for virtually all use. Perhaps with the exception of using the Lumix G 20mm f/1.7 pancake lens, which can some times be a bit slow, due to the combination of a thin Depth of Focus (DoF) and a traditional focus construction moving all the lens elements back and forth.

Here I compare the AF performance of the GH2 with the GH3 with some different lenses. The results are a bit unexpected, for example, the GH2 performs better in some cases. However, keep in mind that the GH3 had the firmware version 1.0 at the time of testing, and also that the focus is still very, very quick in these examples.

The real problem of mirrorless camera systems, though, is the AF-C, continuous autofocus performance, e.g., when tracking moving objects. DSLR systems, while larger in size, can use phase difference autofocus (PDAF) for much better focus tracking of moving subject. The Sony SLT systems, which can operate with the translucent mirror down, can even use PDAF during video recording.

I designed a test to evaluate the continuous autofocus performance during video recording between the GH2 and GH3 cameras. The test shows that the GH3 keeps the subject in focus about twice as often. In my example, both cameras read the sensor output 25 times per second, so the improvement must be due to better image processing. Or, perhaps, one or both of the cameras can read the sensor output between the video frames, for even better video AF performance, but this is speculation. Either way, it is clear that the GH3 achieves better AF during video recording, which is what this system needs.

Here is another test, which compares the focus performance with the Lumix G 14mm f/2.5 in a real life situation. It is clear that the GH3 is way better than the GH2 in this respect. I would say this is a revolution, and the GH3 may be the first Micro Four Thirds camera to make AF during video truly possible.

The test does not indicate the performance of the AF-C mode for still image use, for tracking of moving subjects. I don't use this feature frequently, and I have not compared the cameras head to head in this respect.

However, the GH3 has an ace up the sleeve in this respect: The sensor can read the image at 240 fps (frames per second) for the quickest autofocus performance. This is twice as fast as the GH2. However, the small print says that at the time of launch, this feature is only available when using the GH3 with the Lumix X 12-35mm f/2.8 or Lumix X 35-100mm f/2.8 pro zoom lenses. This feature, as well as the general improvement of the image processing, makes it reasonable to believe that the GH3 improves upon the AF-C performance of previous MFT cameras.

Photography

The GH2 improved the video quality of the GH1, however, I never felt completely happy with the colours of the GH2. The same goes for photographs. The good news, then, is that the GH3 generally gives much better colours and tone straight out of the camera. It also improves the high ISO performance. With the GH2, I felt I could use ISO up to 1600 fairly safely. Using the GH3, I think this limit has been increased to 3200.

Here is a comparison of the image quality at high ISO for the cameras GH1, GH2 and GH3. I think the GH3 image output at ISO 1600 is the best, having best colours and more details in the shadows.

Electronic shutter

One of the fun new features of the GH3 is the electronic shutter. This feature is also found in the Panasonic G5. Here, I have used a LEGO Technic contraption to measure the speed of the electronic shutter: It spends 1/10s to roll across the sensor, potentially creating a host of negative side effects.

The rolling shutter can also be used creatively. Here are a couple of examples:


When holding the camera upside down, you can make passing cars lean forwards.	The vibrating string on this bass creates a sine-like pattern.

In the beginning, I generally kept the camera in electronic shutter mode, except when I needed to use the flash, a shutter speed slower than 1s, or ISO above 1600. However, I grew tired of deleting pictures due to excessive rolling shutter effects, so I now generally use the mechanical shutter, except when I want the shutter to be quiet.

Here are some more examples of the rolling shutter effect, including banding effects when photographing indoor in fluorescent light.

Video

The GH2 had a very good video quality, and I felt no need to apply the "firmware hack" to further improve it. In this test, I put the cameras head to head to examine the quality of the video output. We see that there are small changes. The GH3 handles rolling shutter slightly better, and has better colours, in my opinion. It also has somewhat better dynamic range, and better sharpness and more details at 1080p. Even when looking at footage on YouTube, which compresses the videos, I think that there is a noticeable performance difference between the GH2 and the GH3.

The big change, though, is the increase of the number of video modes available, and also the higher possible bitrate.

Like the predecessor GH2, the GH3 also includes the Extended Tele Conversion (ETC) feature. This increases the reach of the lens by about 2.5x, while still achieving full 1080p resolution. However, the noise performance is not as good, especially at high ISO. In the video below, you can also see that the noise performance in non-ETC mode (normal mode) is quite good even at high ISO.

The GH3 also adds the ISO 6400 option for video recording, which is very useful for recording concerts in dim light, fireworks, and so on. The GH3 can also record video at ISO 12800, using a strange trick that I describe here.

On the negative side, the GH3 is the first camera in the series which does not have the multi aspect, oversized sensor. Read the article linked to see how this affects the video mode.

While a lot of people have been saddened by the lack of the multi aspect sensor feature, it is important to remember that this is no common feature. In fact, this feature has only been seen on the Panasonic GH1 and GH2 cameras: No other system camera has it. On the other hand, many other system cameras use the APS-C sensor, in which there is a smaller difference between the full sensor and the 16:9 video crop.

EVF

Much has been said about the electronic viewfinder (EVF) of the GH3. Many have complained that it smears the image, and is generally useless. While the GH1 and GH2 appeared to have the same EVF optics, the GH3 has a different type of optics, and a smaller lens to look through. The images below were taken at the same enlargement:


GH2	GH3

For a person who wears glasses, this is bad news. The smaller opening makes it more difficult to see the whole image at the same time when using glasses. While I have had no issues with image smearing, like other people have complained about, I think the new EVF is less suited for glass wearers, and does not allow me to see the whole image at once. The image is very clear and sharp, though.

Display

Compared with the GH2, the GH3 gets a long overdue increase of the display screen resolution. Still, at 614.000 pixels, it is lower than much of the competition. The screen appears much more clear, though, so this is good news. It uses OLED technology.

However, this still only corresponds to 480 pixel rows, meaning that it is not possible to use the LCD screen to fully assess the image sharpness when manually focusing during video recording at 1080p.

Flash

Just like all other Panasonic Micro Four Thirds cameras, the GH3 includes a built in flash. As you can see, it is not as tall as the one on the GH2, which is a strange development. Generally, the further from the lens mount, the better the flash works for general use.

Looking from above, though, the GH3 flash is located further to the front, which could be better for dispersing the light over the lens.

But, as one say, the proof of the pudding is in the eating, so let's see how they perform. In this test, I have placed the cameras about 1 meter from a wall, with the Lumix X 12-35mm f/2.8 at 12mm. The lens hood was mounted.


GH2	GH3

As you can see, even if the GH3 flash is lower, it still does a better job of avoiding the lens hood when illuminating the subject.

Wifi

The camera adds a wifi mode. Setting up and using the mode is not as straight forward as it could have been, and the functions generally feel a bit immature. But being able to control the camera from a smart phone is a fun novelty, and also quite useful.

Compared with the Olympus OM-D E-M5

The Olympus OM-D E-M5 predated the GH3 by about half a year, and has been very successful. It has a retro metal construction, and the image quality has generally been praised. They probably share vital sensor components, although their filter and image processing probably differ. For example, the Olympus OM-D E-M5 is said to be quite sensitive to infrared light, while the GH3 is barely sensitive to infrared at all. This indicates that they have different filters in front of the sensors.

In general, I would say the GH3 has the best feature set and the best ergonomics. On the other hand, the E-M5 is a smaller camera, and it includes in-camera image stabilization (IBIS). Personally, I don't like the retro design of the Olympus OM-D E-M5. But I understand many are crazy about it. Also, I think the E-M5 is more awkward to hold and use, with no real grip. The wheels and buttons on the E-M5 appear to have been made to look cool, and not to function ergonomically, I think, however, I know this is a controversial issue.

There is little doubt that the GH3 is the best camera for video performance. For out of camera JPEG images, the OM-D E-M5 is probably the best. If you process the RAW images, then they are probably similar. Here you can read about how using RAW can be useful for improving your images.

I think the choice comes down to your preferences in terms of the design and ergonomics.

Compared with the Panasonic G6

The Panasonic G6 was announced in April 2013, almost half a year after the Panasonic GH3. Still, the GH3 is the better camera in virtually every way.

Not to say that the G6 is useless. Far from it. You may still be interested in the G6 for two reasons, mainly: It is smaller and lighter, and less expensive, while still packing most of the features of the Panasonic GH series.

It has a sensor from the GH2, however, with improved image processing. Sadly, it does not have the multi aspect sensor feature of the GH2.

In terms of video, it improves upon the GH2 features by adding 1080p resolution at 50/60fps (depending on PAL/NTSC), and also supports the extended tele conversion (ETC) mode.

When it comes to the design, it follows the GH3 trend by replacing chrome details with matte black. The overall shape bears a clear resemblance to the Leica R8 and R9, with elevated shoulders. While the camera is small, it has a generous grip, for better ergonomics.

This table sums up the size in comparison with the GH3:

Camera	GH3	G6
Width	133mm	122mm
Height	93mm	85mm
Depth	82mm	71mm
Weight	550g	390g

A video optimized camera?

In online discussions, one often hear people referring to the GH3 as a video optimized camera, and stating that they would rather get a different camera for photography. So is the GH3 is video optimized camera?

I would say quite clearly not. The GH3 is a system camera with a very good video mode. But it is not video optimized. Truly video optimized cameras look quite differently. Video optimized camcorders like the Panasonic AF-AG 100 and the Sony NEX VG30 have a totally different form factor.

Also, if the GH3 is video optimized, why does it not include built in ND filters? And why does it not easily support video recording with a 180° shutter? In fact, in video mode, the camera does not even state which shutter speed it is using, except when using full manual mode. This is far from video optimized, in my opinion.

When looking at the GH3, it is rather clear to me what Panasonic is aiming for: The pro DSLR market. The camera mimics quite well professional cameras like the Canon 7D and the Nikon D800, with twin control dial, weather sealing and a rugged body. When seeing the new lenses that goes with it, this connection is even more clear. The Lumix X 12-35mm f/2.8 or Lumix X 35-100mm f/2.8 lenses correspond to the typical photojournalist pro zoom lenses.

Conclusion

The Panasonic GH3 is a great camera. It marks a new start for Panasonic, a journey into the realm of professional camera systems.

If you value the ergonomics and features, the GH3 is a very good choice.

At the same time, it loses some of the initial advantage of the Micro Four Thirds system: Size.

If you are looking for a more compact camera, you could consider the Panasonic G5, the predecessor Panasonic G6, or the Olympus OM-D E-M5. These do not have all the features of the GH3, but are still very good.

Third party battery for GH3

2013-04-19T14:51:00.001+01:00

A spare battery for a digital camera is a good thing to have. If the battery runs out, the only way to charge it would be to remove it from the camera and place it in the charger, provided you are somewhere with a power outlet. This means not being able to shoot for an hour, at least.

If you carry a spare, charged battery with you, you can just exchange the battery in a matter of seconds, and be ready to shoot again. However, original batteries often cost a lot. The GH3 battery can easily cost US$80 new.

With the GH2, the third party batteries did not let the camera see how much power was left, hence, you would not get any "power bars" in the camera display. And even worse: When the battery eventually run out of juice, the camera would just die instantly, and the images in the buffer, not yet written to the memory card, would be lost. If you were recording video while the battery died, you would lose the video footage.

With the GH3, though, third party batteries are available cheaply, and they let the camera see how much juice is left. So, from the point of not losing data when running out of juice, they are safe to use. Just like when using original batteries, the camera will warn you that the battery power is low. And, eventually, the camera will stop video recording and write the data to the memory card before shutting down.

The battery I tested is marked with "FOR BLF19", indicating that it replaces the original battery called Panasonic DMW-BLF19. Just like the original battery, it is marked with 1860mAh, i.e., the same power reserve.

Here it is next to the original battery, original to the right:

The third party battery feels a bit lighter, but otherwise they appear to be identical.

I have not formally tested if they carry the same amount of power reserve, but so far, the third party battery appears to be as capable.

The third party battery is a good alternative to the original version. It appears to perform as well, and is good to have in the camera bag as a replacement power, for the times when you need it. At the low cost, I would recommend getting a second battery for spare power.

High ISO performance of the GH series cameras

2013-04-14T21:29:00.002+01:00

When new camera generations get launched, everybody expect the high ISO image quality to improve over the previous generations. While we would use a low ISO as possible at all times some years ago, it is generally quite safe to use ISO 800 with newer generation cameras. Let's take a look at how the Panasonic GH series handles high ISO.

To test this feature, I rigged the Panasonic GH1, GH2 and GH3 on a tripod, using the Sigma 30mm f/2.8. I left the lens wide open, it tends to be quite sharp. To be able to compare the cameras, I set both in the Shutter speed priority mode (S), at 1/10s and auto-ISO. The camera would then select the ISO needed for the exposure to be sufficient. I used Auto White Balance (AWB).

Here are the three images:

GH1, 1/10s, ISO 1250

GH2, 1/10s, ISO 1600

GH3, 1/10s, ISO 1600

These are the out of camera JPEG images, with standard image settings. The histogram below shows that all cameras expose the scene pretty similarly. The GH3 exposes it a bit brighter, though:

Another thing to note is that the GH1 uses the lowest ISO value of the three, 1250. This confirms again that the Panasonic GH1 had a somewhat conservative ISO scale, compared with other Micro Four Thirds cameras.

Looking at the image quality, we can compare 100% crops from all three images. I rescaled the GH1 image, to make it comparable with the 16MP output of the other cameras.

I think we can see that the GH2 images look sharper, but at the expense of shadow details. The GH3 appears to give a higher dynamic range, with more usable details in the dark parts of the image. With the advances of high ISO image quality, I feel quite confident using ISO values of 1600, and even 3200 when needed, with the Panasonic GH3.

GH2 vs GH3 video quality comparison

2013-04-06T22:55:00.000+01:00

When Panasonic released the GH3, it was expected to raise the bar even further in terms of video quality. To compare it against the GH2, I connected both cameras to a piece of wood, using Manfrotto Superclamps, so that they would record the same scenery for comparison.

On both cameras, I used the Lumix G 14mm f/2.5 pancake lens, a favourite of mine. I focused on "infinity", and then set both cameras to manual focus. The lenses were set to f/5.6 for the best sharpness, and I used the base ISO on both cameras. With the ambient lighting, the shutter speed was usually around 1/120s. Both cameras had the same settings in terms of sharpening and saturation. It was all recorded in 1080p, 25fps.

Even if the cameras have identical lenses mounted, they still have different field of view during video recording. This is due to only the GH2 having the an over-sized, multi aspect sensor, giving a wider field of view in video mode.

Here are the videos combined, for easy comparison:

Some may doubt that the quality of the YouTube rendering of the video is sufficient to really tell the difference between the cameras. I agree with that, and to assist in comparison, I uploaded parts of the video at 200% size, which probably makes the video image quality easier to assess. And I made some 100% crops from the original out of camera video files, uncompressed in PNG format below:

This last image comparison is from the ISO 1600 footage:

Conclusion

Just like I have concluded previously, the GH3 features somewhat less rolling shutter artefacts in video mode. Further, I think it looks like the GH3 handles high contrast better, and the overall sharpness of the video stream is better. Not unexpected, since the GH3 can record at up to 72Mbps bitrate, as compared with 24Mbps for the GH2. I used 50Mbps with the GH3 here, though. Of course, the bitrate is not everything, the sensor, AA filter, downsampling algorihm and compression algorithm are also important.

I also like the colours of the GH3 better. At high ISO, the GH3 does provide more details.

As far as I can see, the GH3 does deliver on the promise of delivering even better video quality than the predecessor GH2.

AF during video, comparison GH2 vs GH3

2013-04-01T20:58:00.001+01:00

Recent Micro Four Thirds cameras have very good autofocus performance for still images. Mostly, the performance is among the best in this class, certainly better than DSLR cameras in live view mode. However, there is one area where mirrorless cameras don't perform well at the moment, and that is continuous autofocus: Both during video recording, and for photographing moving objects, e.g., for photographing sports and birds.

Some camera manufacturers have been trying to solve this by adding phase difference sensors (PDAF) on the imaging chip, like the Nikon 1 and Canon EOS M cameras. However, the real world benefit of that solution is still undecided.

Panasonic have said in interviews that the on-sensor PDAF solution is not going to be used for Micro Four Thirds, at least not anytime soon. Rather, Panasonic expects to achieve better continuous autofocus performance by using faster image readout from the chip, better image processing algorithms, and more processing power. Have they achieved this with the most recent Panasonic GH3?

To compare the autofocus performance during video recording with the GH2, I used a Lego Technic contraption to move a cardboard box back and forth at a steady pace. I then set up both cameras, in turn, with the Lumix X 12-35mm f/2.8 lens at 35mm f/2.8 at close range, and recorded video at 1920x1080, progressive, 25fps. Comparing the resulting footage, it is easy to see which camera better finds the focus during the movement. Here is the video footage, for comparison:

It's easy to see that the GH3 achieves correct focus more often than the GH2, in fact, about twice as often, according to my frame counting. The GH3 also has a better overall sharpness: It is possible to see the offset printing pattern more easily with the GH3. This could be partially due to the multi aspect sensor feature that the GH3 misses: It means that you get slightly narrower field of view when using the GH3, as compared with the GH2, and hence, more enlargement of the subject.

One of the new features of the GH3 is the 240fps contrast detection autofocus (CDAF) sensor readout. The GH2 only does 120fps, maximum. The smaller print in the GH3 specifications state that the 240fps is only possible when using the newest f/2.8 zoom lenses, the Lumix X 12-35mm f/2.8 and the Lumix X 35mm-100 f/2.8.

And can the camera use the 240fps feature during video recording? Probably not, since the sensor is busy reading the image at 25fps for the video stream anyway. I previously compared the GH2 video AF performance during 25fps and 50fps video, and found that it does better at 50fps, indicating that more frequent image readout is better for the AF performance. As long as the shutter speed is faster than the video rate, there is surplus time between the frames for CDAF readout. Perhaps the GH3 camera can utilize this for better AF performance?

Conclusion

The Panasonic GH3 camera appears to be able to focus better during video recording than the GH2, even at the same frames per second (fps) rate.

Timelapse with the GH3

2013-03-28T13:08:00.001Z

One of the new, fun features of the Panasonic GH3 is the timelapse mode. Sure, one could do the same thing with previous cameras as well, given that you buy an external controller to connect to the camera's remote shutter release socket. But having the timelapse possibility built into the camera is easier.

To make an example timelapse video, I first set the camera on a tripod over my table, like this:

I'm using the Manfrotto 190XPROB tripod, which is useful since the column can be set horizontally. The ball head is Benro B-2, but most ball heads can be used here.

I used the Lumix G 14-42mm f/3.5-5.6 kit zoom lens at 14mm, and set the aperture to f/3.5. This was done mostly to avoid the aperture closing and opening for each shot, which is a somewhat annoying ticking sound. I prefocused, and then set the camera to manual focus (MF), to avoid the camera engaging the autofocus mechanism for each shot. I also used the electronic shutter mode of the GH3.

Since I was planning to make a video from the timelapse, I set the aspect ratio to 16:9. And to avoid bogging down the memory card with too much data, I deselected the RAW option, and only used the lowest quality JPEG option, as indicated by the three blocks in the mode display below:

Setting up the timelapse is very easy. Just go to "Timelapse" in the Photo menu, and then set how often and how many images you want. I selected one image per every six seconds, and set a total of 1111 images:

I wasn't planning to use all the 1111 images, this just gave me enough slack, and I can stop the time lapse when finished. Then, it's just a matter of starting the timelapse.

I wanted to make sure the output images were scaled down to 1920x1080 and then sharpened using a sensible algorithm, so I used the ImageMagick tool "convert", in Linux. Converting all the JPEG images at once can be done with this command line:

$ find . -name "*.JPG" -exec convert -unsharp 0.5x0.5+0.5+0.008 -resize 1920x1080\! {} {}.PNG \;

The converted images are made into PNG images to avoid loss of quality in this process. To compose a video out of the still images, I used the program MEncoder, released together with MPlayer.

$ mencoder mf://*.PNG -mf fps=8:type=png -ovc x264 -x264encopts bitrate=24000:threads=2 -o video.mkv

I set 8 frames per second (FPS). And here is the output video:

In the time lapse, one can set a long delay between each shot, i.e., several minutes. If so, the camera enters a sleep mode between each shot. Setting manual focus still works, even if the lens focus is reset between each frame. Apparently, the camera has indexed the focus position.

GH3 electronic shutter

2013-03-27T21:57:00.000Z

I've written about the electronic shutter feature of the Panasonic GH3 before, concluding that the feature is very useful, but has some side effects. The electronic shutter is useful since it is totally silent, and vibration free. However, the electronic shutter reads the image sequentially, row for row, rather slowly, taking about 1/10 second in total. If you move the camera during this time, you get odd wobbly effects, even with a very fast shutter speed. This is a rolling shutter artefact.

To illustrate this, I have superimposed two exposures in an animated GIF. They were taken with the Lumix G 14mm f/2.5 at f/4, 1/60s, ISO 200. Normally, one would think that 1/60 second is safe for handholding a shot with a wide angle lens, however, since each full exposure takes 1/10 second, any movement during the exposure will result in a skewed image:

Looking at only one of the two exposures above, one might not notice any problems. However, when seeing both, it is clear that at least one of them, probably both, are not geometrically correct. So, is this a problem? When holding the camera reasonably still during the exposure, and not photographing very square objects, it is no issue. If you critically need rectilinear images, then you are better off using the normal mechanical shutter.

In artificial light

For about a century or so, people have been using incandescent light bulbs for electronic indoor lightning. Even when used on alternating current (AC), the light is stable. Since the filament is heated, it emits light also when the alternating current is at zero.

However, traditional incandescent light bulbs are now being replaced with the energy saving fluorescent light bulbs. They tend to flicker at 100Hz (in Europe) or at 120Hz (in the US). The lights don't flicker at 50Hz and 60Hz, as you might expect. This is since during each period, the electrical current reaches two peaks, see the illustration below:

As the Panasonic GH3 takes 1/10s to record an image in electronic shutter mode, the flicker can be a problem. Any shutter speed faster than 1/100 second will be a problem.


1/200s	1/400s

The fastest shutter speed which is safe, is 1/100s (or 1/120s if you are in a 60Hz country, like the US). But don't think that a slower shutter speed will be ok. A slightly slower shutter means that you capture two of the peaks at some points, giving banding again. Below are the exposures at 1/100s and 1/80s. Only 1/100s is ok, since I am on a 50Hz power grid:


1/100s	1/80s

On a 50Hz power grid, the safe shutter speeds are 1/100s, 1/50s, 1/25s, and so on. In the US, you should aim for 1/120s, 1/60s, 1/30s, and so on. When photographing indoors, you are likely to use a slow shutter speed, so this is not likely to be a big problem.

We can also see that there are ten bands of grey periods in my pictures, indicating that the rolling shutter exposure takes around 1/10s. This is exactly what I concluded using my Technic LEGO contraption earlier!

Creative use

What is a negative side effect to some, can be a creative possibility for others. The rolling shutter effect can be used creatively, to create interesting images. One way is to photograph moving objects, to make it lean. An obvious choice can be a moving car, 1/1600s, ISO 400:

If you want the car to lean the other way, then you must hold the camera upside down!

Also, when photographing vibrating items, you can get fun effects. Here, I have photographed a bass player's hand:

The picture was taken at with the Lumix X 45-175mm lens at 175mm f/5.6, 1/800s, ISO 200. In retrospect, I should have set the ISO higher, to achieve a faster shutter speed, and better defined green string, with less motion blur.

When taking a picture like this, it is important not to move the camera during the exposure, otherwise, you get the negative rolling shutter effects. Here, my hand has apparently shaken a bit during the exposure, giving a slightly S-shaped guitar:

It is also important to have the vibrating string vertical. If it was horizontal, you would get a different effect.

Here is a guitar player as well:

Less vibrations

On the positive side, using the electronic shutter reduces the vibrations. This can be good when using a long lens on a tripod. The mechanical shutter can start a vibration, which will reduce the sharpness of the image. Now, this is rather theoretical, so let's try to see an example. I put the camera on a tripod, used a Lumix G 100-300mm f/4-5.6 at 300mm f/5.6, 1/30s, ISO 200, using a 10 second shutter delay to avoid vibrations. Here are 100% crops from the resulting images when using the electronic shutter (left) and the mechanical shutter (right):

As you can see, the image taken using the electronic shutter is slightly sharper than the one taken using the mechanical shutter. This is probably due to the mechanical shutter setting off a small vibration, reducing the sharpness when using a long focal length. However, the difference is rather subtle, and would probably not make much of a difference in a real life example. If you have an even longer lens, then this might be more important to look into. There are, at this time, no native lenses longer than 300mm. But it is possible to use legacy lenses on adapters.

ETC comparison, GH2 vs GH3

2013-03-24T10:55:00.000Z

I recently looked at the video quality when using the ETC function, as opposed to using non-cropped video on the Panasonic GH3. My conclusion was, perhaps not surprisingly, that the ETC function adds quite a bit of noise at higher ISO. So while the ETC function is very good to have for extending the reach of your lenses during video mode, you should avoid using it at high ISO unless you really have to.

But what about comparing the GH3 with the predecessor GH2. Both cameras feature the ETC mode. To test this, I set up both cameras to video record the same scene, and used the Lumix G 100-300mm f/4-5.6 lens at 100mm f/5.6. I already know that this lens is very sharp at 100mm, especially when stopped down to f/5.6.

Here is a comparison of the videos outputs:

Also, here are some 100% crops from the video streams:

I think that the cameras perform quite similarly, in this case. I'm actually thinking that the GH2 videos look better in terms of sharpness and noise at ISO 3200. The GH3 has better colours, though.

Of course, the GH3 goes all the way up to ISO 6400 for video, also for ETC, which is an advantage over the GH2 anyway.

One can also argue whether ISO 200 is the same with both cameras. Do the cameras have the same sensitivity at ISO 200, and at higher ISOs? I don't think the jury is fully out on this yet. To try to assess this, I tried to take images at ISO 200 with the cameras GH1, GH2 and GH3. However, even after seeing the results, I am not sure how to interpret them.

Conclusion

The ETC mode is very useful, but avoid using it at high ISO, where it adds quite a bit of noise. The GH2 and GH3 appear to be quite similar in this respect.

Using the Lumix G 100-300mm f/4-5.6 at 300mm in combination with the ETC mode gives an effective reach of around 1500mm equivalent, filling the moon into almost the entire video frame:

Tele lenses and perspective

2013-03-20T20:07:00.001Z

One can often hear phrases like "tele lenses can be used to compress the perspective, and make things that are far apart appear close". But it is true?

As the statement it written, it is wrong. A simple geometric argument shows that the perspective only depends on the distance from the camera to the subject, regardless of the field of view, regardless of the lens.

But why believe a geometric argument? We can look for ourselves at a real life example. This image was taken with the Lumix G 100-300mm lens at 300mm:

In the image, it looks like the construction cranes are just behind the neon "Freia" logo on the front rooftop. But in reality, the distance is 1 km. This is what we normally call a compressed perspective.

But is it the long focal length which produces the compressed perspective, as the statement initiating this article? We can see for ourselves, by setting the lens to 100mm, and photographing from the same point. That gives this image:

Does this image have a different perspective? We can crop the centre of the 100mm image and compare it with the 300mm image:

We see that the images are exactly identical. There is no difference in the perspective, demonstrating that the perspective only depends on the placement of the camera, not the focal length.

On the other hand, if I change the point from which I am photographing, as well as change the focal length, then I get a totally different perspective, as illustrated:

Here is the same building photographed much closer with the Lumix G 14mm f/2.5, a wide angle lens:

Now, the perspective is not compressed anymore. But was this due to the wide angle lens? No, I would say, it is because I went closer to the subject.

But, it was the wide angle lens which allowed me to go closer to the subject. Just as it was the tele lens which allowed me to go far away from the subject, to create a compressed perspective.

So while it is not true to say that a tele lens compresses the perspective, it is true that the tele lens allows you to step further from the subject, to achieve a compressed perspective. So, at the end of the day, it is perhaps not so wrong to say that the tele lens compresses the perspective, as this is what you achieve when using the lens anyway.

Conclusion

Having some focal length range available, either as a superzoom lens, or as some different prime lenses, is useful. It allows you to achieve various perspectives, by varying the distance to the subject.

GH3, quality of ETC video vs non-ETC

2013-03-16T21:11:00.000Z

Just like the predecessor GH2, the Panasonic GH3 has the ETC (Extended Tele Conversion) mode. This is useful for videos, when you need more tele effect, a longer reach.

Normally, the camera uses the whole imaging sensor during video, and scales the output down to 1920x1080 pixels for the video stream. In ETC mode, though, it only uses the central 1920x1080 pixels of the sensor, giving an effective 2.4× crop factor, while retaining the full resolution, see the image below:

With the Panasonic GH2, the ETC crop factor was 2.6×. The reason for the difference is that the GH2 has an oversized, multi aspect sensor. The GH3 does not.

Let's say that you use the Lumix G 20mm f/1.7 pancake lens. When using ETC during video recording, it effectively becomes 48mm f/1.7, with 48mm = 20mm × 2.4. Which can be useful at times.

The ETC mode can be enabled in the video menu (left below), or by using the Q-menu (right below):

This feature is very good to have when you want to record videos at a long tele, and you don't have a long enough lens. However, since the camera has fewer pixels to use for making the video stream during ETC mode, one can guess that the quality will suffer. Unlike when using the full sensor, there is no possibility to scale down the image for better noise performance.

Comparison: Non-ETC video vs ETC video

To compare the non-ETC output with the ETC output of the GH3 camera, I recorded video sequences using the Lumix X 12-35mm f/2.8 lens at 35mm without ETC, and at 14mm with ETC. Both these two modes give approximately the same field of view, since 14mm multiplied with the ETC crop factor 2.4 gives approximately 35mm.

I used f/5.6 for the best sharpness. In both these modes, I used ISO values from 200 to 6400. I used the 25fps 1080p, ALL-INTRA mode for the best video quality.

Normally, one would of course not use the ETC mode with the Lumix X 12-35mm f/2.8 lens at 14mm. It would be better to just zoom the lens to 35mm. However, using this trick, I was able to compare the non-ETC and ETC modes using the same lens.

Here is a video summary of the comparison:

And here are 100% crops from the videos, for comparison. The normal non-ETC images are on the top, and the ones with ETC on the bottom:

We see that even at ISO6400, the non-ETC video footage holds up pretty well. It is a bit noisy, and the colours are not as good, but the video is still usable. With ETC, though, the quality degradation is much more severe.

Conclusion

The ETC mode is a very useful feature, but it is best used at low ISO. At higher ISO, the video quality will suffer. We also see that even at ISO 6400, the video quality is quite good with the normal, non-ETC mode.

We don't know exactly what algorithm the GH3 uses for scaling down the video stream from the full sensor to the 1920x1080 pixel output. It probably does not use every 11 million pixels of the sensor (in the 16:9 subsection of the sensor area), that would take too much processing power. But it is clear that it does use some averaging technique, to keep the noise down. In ETC mode, there is no scaling down, and hence, no noise reduction from using more pixels.

I've also compared the ETC video quality of the GH3 with the predecessor GH2. They seem to perform quite similarly, although I generally like the colours of the GH3 better.

When using ETC with a long lens, you can get an extreme tele reach. In the example below, I am using the Lumix G 100-300mm f/4-5.6 at 300mm, together with the ETC mode. This gives a very compressed perspective, due to the extreme tele effect.

You'll see the image wobbling. This is due to atmospheric disturbances, since the light travels through a lot of air before it reaches the camera. There is no way to avoid this, beyond, perhaps, getting up early in the morning while the air is cooler.

When using the Lumix G 100-300mm lens at 300mm, and with ETC, the effective equivalent focal length becomes 1500mm, which is a lot. Even when placing the camera on a tripod, I had to remove the first seconds of video footage while waiting for the camera and lens to settle down after pressing the shutter button.

New firmware for GH3

2013-03-10T19:45:00.001Z

Panasonic has announced that a firmware upgrade for the Panasonic GH3 will be available by the end of March. The firmware upgrade improves the autofocus performance on some newer zoom lenses, like the Lumix X PZ 14-42mm and Lumix X PZ 45-175mm lenses. It also makes it easier to connect to Wifi when using Mac computers, and adds a video mode.

When the new firmware is released, some people will try to decipher the firmware, and try to make changes to it. Most likely they will not be able to add genuinely new features, but perhaps they can make changes to parameters like the video bitrates. This is usually called "hacking the firmware". The GH1 was popularly hacked, giving the possibility to use a higher video bitrate.

Panasonic can also, if they invest the time and resources, add new features to the camera with a new firmware upgrade. Here are some of my ideas for new features, or changes to existing settings:

Dropping RAW images when the buffer is full in continuous drive mode

The GH1 and GH2 were plagued with horribly slow buffer clearing speeds. The GH3 improves significantly on the predecessors in this area, however, you may still run into problems with taking consecutive images fast enough for when recording both RAW and JPEG images, even with a fast SD card.

My suggestion is a new setting, in which the camera only records both the RAW and JPEG files as long as the buffer is not full. When the buffer is full, it could revert to only recording the JPEG image. That way, you can sustain a high frame rate for a longer time.

And you can use one single mode at all times, without having to change mode when you need to take a lot of consecutive images. Such a feature will give you access to the RAW images most of the time, except when you happen to need a long series of consecutive images.

Remove the electronic shutter ISO 1600 limit

The GH3 has a very useful electronic shutter feature. However, it is limited to ISO 1600. Perhaps Panasonic have introduced this constraint for a reason, there might be some adverse side effects when using higher ISO. But anyway, allowing for higher ISO in electronic shutter mode could be useful, even if there is some risk of degrading the image quality slightly.

Auto ISO available in Manual mode

In the Manual (M) exposure mode, the auto ISO features are dropped. This is a strange choice to me: If the auto ISO settings were available, you could set the aperture and shutter speed manually, and the camera would select an appropriate ISO to match the exposure, if possible. If you need to set the ISO manually in M mode, that is of course still possible.

The Pentax DSLR models support this feature, and I think it is very useful. This could easily have been fixed with a firmware upgrade.

Focus peaking mode for manual focus assist

Some Sony camera models feature "focus peaking", in which an outline is highlighted when an object is in focus. This is useful for manual focusing, especially during video recording.

A Panasonic engineer was quoted saying that this could not be done with the GH3, due to image processing constraints. Perhaps this is true, but I still think that some focus peaking feature could have been implemented into the GH3.

To add to the confusion, a Panasonic engineer has later been quoted saying that the focus peaking mode could be added with a later firmware upgrade, but not now in March.

Other ideas?

Do you have ideas for other features Panasonic could cram into the GH3 using a firmware upgrade? Please suggest in the comment field below!

Why use RAW?

2013-03-06T21:38:00.001Z

You'll often hear people recommend to use the RAW image file format. But why? What is the reason for using the RAW file format? In this artice, I'll look at an example where it makes a difference.

Most serious cameras have the possibility to record the images in two different file formats: JPEG and RAW. The RAW file format can be of many different types and extensions, but they all have some things in common: The RAW files take up much more space than the JPEG file, and they contain the image as seen by the camera sensor, mostly without any adjustments.

This is in contrast with the JPEG files, which are compressed to take up less space, and where the camera has tried to interpret the image how it thinks you want to see it. With the RAW file format, you can later develop alternative JPEG output files by altering how you want the original RAW file to be interpreted.

Here is an example JPEG image. It was taken with the Panasonic GH2 camera, with the Lumix G 14mm f/2.5 lens at ISO 640, f/2.8, 1/10s.

The shutter speed is too slow for taking a picture with this lens, according to conventional wisdom: To be reasonably sure to avoid camera shake blur, one should use around 1/30s or faster with a wide angle lens like this. However, in this case, I preferred to use a slow shutter speed, and avoid using the flash or a higher ISO. Using the flash would have changed the style of the photo totally. Besides, I like the effect of the slow shutter: The trailing lights from the sparks coming out of the pipe can be seen. And the image is still reasonably sharp.

The picture was taken late dusk, which is what gives it the blueish tint. The blue colour is correct: The scene was in fact blue due to the timing, just after sunset. However, by using the setting "Twilight" in the RAW developer program Silkypix, I can get more natural looking colour tones:

This image has a totally different appearance, with more normal skin tones, and less blue.

One could also go the other way, and exaggerate the blue dusk colours, by changing the white balance and increase the saturation:

Some would say that the colours now look unnatural, others might prefer it for the stronger colours. But the point is that when you have the RAW image, you are free to make these choices later. With only the JPEG image, it is more limited what types of adjustment you can make, without significantly losing colour details.

With that said, you are less likely to want to make colour tone adjustments to images taken in daylight, with a proper exposure. In those cases, you are often well served with the JPEG image only. In my opinion, the RAW image is of more use when the there is dim light, and when the exposure is uncertain. In sufficient daylight, with normal contrast, the camera often does the right choices with the out of camera JPEG image.

Pentax K-01 is history

2013-03-01T17:52:00.001Z

Pentax has now ceased the production of their only large sensor mirrorless camera, the K-01:

The camera was in production for about one year. It was without doubt the most unusual mirrorless camera of all, for a number of reasons.

First of all, it is large. The main reason is that it does not employ a shorter register distance. When removing the mirror assembly, the other mirrorless systems also shorten the register distance, allowing for a smaller camera body. Also, the shorter register distance allows for constructing smaller lenses. Especially wide angle lenses can be made smaller this way.

Pentax's choice of retaining the same register distance and lens mount as their DSLR cameras has a clear advantage: They don't need to create a whole line of new lenses. Hence, their investment is much smaller than that of the Micro Four Thirds and other mirrorless systems: Panasonic and Olympus needed a whole array of lenses to be a viable alternative to existing DSLR systems.

While the camera was launched together with a new 40mm pancake lens, this lens is based on an existing lens design for their DSLR line of cameras, and, hence, is not really new.

Also, the Pentax K-01 is a very unusual looking camera. Designed by Marc Newson, it is a camera you either lover or hate. The camera probably lets form go over function, but still is quite good to handle, and has some charm.

Technically, there is nothing wrong with the camera. It has much of the same sensor and imaging pipeline components as their K-5 semi-pro camera model. It has sensor shift stabilization, otherwise only seen in the Olympus M4/3 camera models in this market segment. It can even accommodate old style screwdriver style focusing with legacy Pentax AF lenses.

Thus ends the era of the strangest mirrorless camera so far. It now sells at a reasonable price, and you have a chance to snatch up this piece of history if you are into collecting.

Using protective filters on lenses

2013-02-26T21:40:00.000Z

One of item of controversy, is whether to use protective glass filters on lenses or not. Typically, people fall into one of two categories:

1) Those who think that having a clear glass filter on the front of the lens is crucial for protection of the front lens element: If you accidentally bang the lens into something, the filter will take the blow, protecting the much more expensive lens underneath it.

2) On the other hand, there are those who think that the filter does little to protect the front lens element: It is much less strong, since it is thinner than the front lens element of the lens is. Also, if it does break, the shards from the broken filter could further damage the lens. The naked lens might not have been damaged at all by a similar blow, according to this group. This group also tends to propose using a lens hood for protection, and to say that any filter put outside the lens will degrade the image quality.

Now, it is hard to say which group is correct. I'm certainly not going to bang my lenses into a sharp object to see what kind of damage it takes.

But one thing that can be tested is if the filter degrades the image quality. I tried to use a cheap filter previously, and found that it did degrade the image quality significantly in high contrast situations, at night. This time, I use a somewhat more expensive filter, which claims to be multicoated:

Hoya HMC multicoated slim frame 58mm

I used it on the Lumix X 12-35mm f/2.8 lens. Here is a picture taken at 35mm at night, both without and with the protective filter:


Without filter	With filter

The only difference I can see here, is that the full moon has moved between the shots. It appears that the filter does not add any extra flare, unlike my previous test with a cheap filter.

I can compare the sharpness by looking at 100% crops from both images:

This comparison shows that there is in fact some loss of sharpness when using the filter. The image is not as crisp on pixel level. However, you can ask yourself if you really need that much sharpness on pixel level.

Here is another test with the lens at 12mm:


Without filter	With filter

In this case, there is a very subtle difference in the flare: Slightly more flare when using the filter:

But beyond this rather subtle difference, there is no significant difference between the image taken with and without the filter.

In daylight, when the contrast is smaller, there tends to be even less impact of using filter.

Conclusion

Based on this and my previous test, I can conclude that using a cheap, non-coated filter can seriously degrade your images, especially in high contrast. However, a reasonably priced multicoated filter can be used with little risk of degrading the image quality. If using a filter like this gives you peace of mind in terms of avoiding damage, then you don't risk damaging the images significantly either.

You can buy a filter like this on Amazon.

Appendix: Technical details

I took the images with a Panasonic GH2. I would have preferred to use my GH3, however, it is still with Panasonic for a repair. After some weeks of use, the automatic switching between the LCD and EVF stopped working.

The camera was set on a tripod, with OIS turned off, the ISO set to 160 (base value). I refocused for each shot, also after mounting the filter for the second otherwise identical shot. I used the self timer to avoid camera shake. The aperture was set to f/4, and the shutter speeds were around 1-2s.

Sigma 19mm f/2.8 EX DN review

2013-02-20T21:21:00.001Z

The Sigma 19mm f/2.8 EX DN was released at the same time as the Sigma 30mm f/2.8 EX DN. Together, these were the first Sigma lenses designed specifically for mirrorless camera systems, and were released for the Sony E-mount and Micro Four Thirds mount in 2012.

Both of these lenses have somewhat odd focal length for the Micro Four Thirds format, compared with conventional prime lenses. The 19mm lens has the same field of view as a 38mm lens on a traditional film camera, while the 30mm lens corresponds to 60mm. Both of these focal length equivalents are unusual.

However, the answer to these odd focal lengths lie in the fact that the lenses were designed for the APS-C format. With a smaller crop factor of 1.5x, the lenses correspond to the 28mm and 45mm, i.e., the classic wide angle and normal lens, respectively.

Also, keep in mind that while 19mm is an odd focal length for Micro Four Thirds, it is very close to 20mm, and the Lumix G 20mm f/1.7 is a very successful lens. They are both shown below:

Physical appearance

First of all, just like its sister lens the Sigma 30mm, this lens rattles. Something is loose inside the lens when it is not in use. This is a bit annoying, but no problem. Once the lens is connected to a camera, and the camera is turned on, the rattling stops.

Again, just like the Sigma 30mm, the rear lens element is recessed quite far into the lens mount:

Since the register distance of the Micro Four Thirds format (20mm) is fairly close to that of the Sony E-mount (18mm), this does not seem to be the explanation for the very recessed rear element. I'm guessing the explanation is that the lens was designed to be used also on the Samsung NX mount, which has a significantly longer register distance of 25.5mm. At this time Sigma has not released the lenses for Samsung NX, but perhaps they will in the future if the format takes off.

The exterior of the lens is black matte plastic, and it has a quite non-obtrusive look.

The focus ring is wide, and made out of ribbed plastic. It rotates smoothly, with a reasonable amount of dampening. The focus is of course "by wire", just like virtually all the other Micro Four Thirds lenses. There is no mechanical connection between the focus ring and the actual focus distance of the lens. And there is no focus scale.

Autofocus

There is a small start-up delay when powering on the camera, unlike most other lenses. The delay is around 1.5 seconds, shorter than for the Sigma 30mm lens.

The autofocus is fast and virtually inaudible. Here is an autofocus speed comparison with the Lumix 20mm f/1.7 pancake lens. As expected, the 19mm lens focuses much faster. There is also a big difference when using the lenses for video. Here is a side by side comparison with the 20mm lens, which shows much better performance when using the 19mm lens. Both lenses are set to f/2.8:

While the autofocus speed is not quite as fast as the modern zoom lenses, it is still more than fast enough, and should be no problem at all for normal use.

Sharpness

I made a sharpness comparison with the Lumix G 20mm lens. It shows that the 20mm lens is the best, no doubt about it. But the Sigma 19mm lens is still quite good.

Here is another sharpness test, compared with the Lumix X 12-35mm f/2.8. The full images at f/2.8 are here:


Sigma 19mm f/2.8	Lumix X 12-35mm f/2.8

In terms of sharpness, the two lenses are fairly equal in the centre. However, in the corner, they are far apart. Here are 100% crops from the top left corner:

We see a quite clear difference. The Sigma 19mm lens suffers from some Chromatic Aberration artefacts (red and green fringing). While the colour fringing can be corrected in an image processing program, there is also some more general dullness. When stopping down, the performance improves some.

Geometric distortion

The Lumix G 20mm f/1.7 lens relies on in-camera geometric distortion correction. The Sigma 19mm f/2.8 does not. However, the output image is not 100% rectilinear, as you can see below.

This is not that unusual. In fact, the Lumix 20mm lens, even after the in-camera adjustment, features some residual barrel distortion. And when photographing people or nature, this is no issue at all, nobody will notice the barrel distortion. But if you use this lens to photograph cityscapes and architecture, you will surely find this problematic.

Bokeh

I compared the bokeh of the 19mm lens with that of the 20mm and 12-35mm lenses here. The 19mm lens has more pleasing bokeh than that of the Lumix G 20mm f/1.7.

Compared with the Sigma 30mm f/2.8

In my opinion, the Sigma 30mm f/2.8 EX DN lens is quite good considering the price. The 19mm lens does not shine quite as much, with more CA artefacts in the corners, and a lower level of sharpness. They both have nice bokeh and fast focus, though.

Compared with the Lumix G 20mm f/1.7

Make no mistake about it, the Lumix G 20mm f/1.7 is a better lens. It is sharper, faster (in terms of aperture), and much more compact. In terms of bokeh, though, I think the 19mm lens is better. The 19mm lens also focuses much faster, and less audibly. For video, I would use the 19mm lens, unless I really need the extra aperture, and can do without autofocus.

Lens	Lumix G 20mm f/1.7	Sigma 19mm f/2.8
Focal length	20mm	19mm
Aperture blades	7	7
Aperture range	f/1.7-16	f/2.8-22
Lens elements/groups	7/5	8/6
Front lens thread	46mm	46mm
Diameter	62mm	61mm
Length	26mm	46mm
Weight	100g	140g
Minimum focus	0.2m	0.2m

You may consider to buy the Sigma 19mm lens over the Lumix 20mm lens to save money, as there is a significant price difference. Or if you need a better autofocus performance during video. But for the best optical performance, the Lumix G 20mm f/1.7 is the better choice.

New version of the lens

This lens is in fact already discontinued. Replacing it is a new version of the lens, called Sigma 19mm F2.8 DN, and is part of Sigma's "Art" line of lenses. It has the same optical design, but a different exterior. The focus ring is now made out of smooth metal:

From an ergonomic point of view, this is a strange choice. While I have not handled the new lens, it looks like a smooth metal focus ring will be less convenient to use. It looks like the remake is all about a new styling, and not any change to the optical properties.

Example images

Here is an example image to illustrate the out of focus rendering at close focus image, at full open, f/2.8. The focus was set to the rose in the lower left corner:

The bokeh is generally very nice, however, there is a bit of ringing in the top right corner.

Another example image, with a focus distance of about 3 meters, at f/3.2, 1/60s:

And here are some 100% crops, which illustrate the CA artefacts in the top left corner, and that the quality is good in the centre:

Conclusion

While the Sigma 30mm f/2.8 gave a good value for money in terms of optical performance, the Sigma 19mm can be seen as more lacking. And with the Lumix G 20mm f/1.7 outperforming the Sigma 19mm, it is hard to recommend the Sigma lens, unless you are on a tight budget, or if autofocus performance during video is important to you. The Sigma 19mm lens is not bad, far from it, it just doesn't reach up to the Lumix G 20mm lens, or the sister lens, the Sigma 30mm f/2.8.

Lens disappointment, Lumix G HD 14-140mm

2013-02-13T20:25:00.005Z

Normally, I write the most about the lenses I like the most. I guess this is partly natural, to write about what is positive, and also reflecting my nature. But, this time, for a change, I write about a lens that has disappointed me: The Lumix G HD 14-140mm f/4-5.8.

To put it shortly, I think this lens has failed to live up to the promise: It is not very sharp, with the exception of the middle of the zoom range. Also, it does not focus faster than the other, and much cheaper, zoom lenses, nor does it operate less loudly, both of which were the claims of the "HD" branding.

The lens was originally launched in 2009, and for the first period only sold in a kit with the Panasonic GH1. It was marketed as a video optimized superzoom lens, and said to have a very quiet, accurate aperture mechanism, capable of near stepless changes. Some have said that the aperture can change in 1/6th stop steps.

It is fairly well known and agreed that the lens is dull in the long end. To further make this claim more credible, here is a comparion of the sharpness at 100mm, where significantly less expensive lenses come out much better. In this test, I am comparing the lens to the Lumix G 14-42mm f/3.5-5.6 and the Lumix G 14mm f/2.5 pancake lenses at 14mm, and conclude that both of the latter are significantly better. So in my experience, the 14-140mm lens only really shines in the middle of the zoom range.

When measuring the autofocus noise, the lens comes out at a fairly average level, comparable with all the other zoom lenses. Also, the aperture change noise was measured to be at a higher level than the other zoom lenses, not really any impressive. This suggests that the HD designation of the lens is rather worthless, as non-HD lenses perform as well, or even better.

The aperture range of the lens is also not so impressive, f/4-5.8. Competing superzoom lenses tend to have the aperture range f/3.5-5.6. Also, when looking at the aperture as a function of the focal length range, you'll see that it very quickly goes up to f/5.8:

Given these experiences, it is perhaps only fair that this lens is now rumoured to get a makeover. A picture of a new version of the lens has been seen. The new lens retains the same basic specifications, but is smaller, with a 58mm front lens thread. The original lens has a 62mm lens thread. The 58mm front lens thread is the same as is used on the Lumix X 12-35mm f/2.8 and Lumix X 35-100mm f/2.8 pro spec zooms.

Since making the original 14-140mm lens, Panasonic has come a long way. The new X branded f/2.8 zooms are very good, and I am sure that with this experience, Panasonic can design a much better 14-140mm lens.

Since writing this article, the new lens has been announced, and it has the more attractive aperture range of f/3.5-5.6, in additon to being smaller and lighter. I would definitively go for the new version, if I had the choice now.

One picture, different times

2013-02-10T20:12:00.000Z

I had the possibility to photograph a nice view early in the morning, and took two images spaced by 29 minutes, to see the difference. I used the Panasonic GH2, since my GH3 is still in for a warranty repair. I did not have a tripod, and handheld the camera with the Olympus 45mm f/1.8 lens.

The first picture was taken at 7:41 in the morning, 35 minutes before sunrise, at ISO 1600, f/2, 1/25s:

The second was taken at 8:10 in the morning, six minutes before sunrise, at ISO 160, f/2.5, 1/45s:

In practice, I took a series of four images in both cases, and then later chose the least blurry of them. That's how I handled the slow shutter speeds without a tripod.

I think most would agree that the first image is the most striking, at least at first glance. It has the deep blue tint associated with the early morning, and there is the contrast with the yellowish artificial lights.

To be able to photograph the first one without a tripod, I needed to push the ISO rather high, at ISO 1600. This is at the border of what the GH2 can handle, and the image quality suffers. Here is a comparison at pixel level between the images shot at ISO 1600 and ISO 160:

Note, though, that this difference is not purely due to ISO differences. The first image also has a slower shutter speed (1/25s versus 1/45s) and a larger aperture (f/2 versus f/2.5), both potentially making the image less sharp. The Olympus 45mm f/1.8 lens is quite sharp, but you'll usually notice that the sharpness increases quite a bit when stopping down from f/1.8 to, say, f/2.8. Despite this, I think the first image could well be printed fairly large without any problems.

The pictures above are from the out of camera (OOC) JPEGs. One could say that the first of the images is rather blue. However, this is not the GH2 auto white balance doing anything wrong, it was quite simply very blue this early in the morning. Opening the RAW image in Lightroom 4, it could be edited to something like this:

I think this edited version is probably a bit more striking.

Conclusion

After having looked at these images, I think it is quite impressive that it is possible to take a handheld image half an hour before sunrise, and even with a tele lens to boot. This shows how far the technological development has come.

Still, the image quality could be improved by using a tripod. If I had a tripod, I could have set the shutter speed to, e.g., 1 second, and used a significantly lower ISO, and a larger aperture for the best image quality.

Bokeh comparison @ 20mm and 19mm

2013-02-07T21:28:00.001Z

The Sigma 19mm f/2.8 EX DN lens can be an interesting alternative to the Lumix G 20mm f/1.7. It focuses significantly faster for both stills and movies, and while it is not as sharp as the 20mm lens, it is still sharp enough. It also comes at a much lower price.

Lumix G 20mm f/1.7 and Sigma 19mm f/2.8 EX DN

In this article, I'm looking at the out of focus rendering of the lenses, the bokeh. I also threw the Lumix X 12-35mm f/2.8 into the comparison.

The comparison was done by focusing on a close object, the box at about 50cm distance in the left foreground:


Sigma 19mm @ f/2.8	Lumix G 20mm @ f/2.8	Lumix X 12-35mm @ f/2.8

Here are some 100% crops from the centre:

And from the extreme right border:

The Lumix G 20mm f/1.7 features asymmetrical out-of-focus rendering outside of the centre of the frame: The further from the centre, the more elliptical the bokeh highlights become. You can see the same phenomenon in this study. This property is also shared with the Lumix-Leica 45mm f/2.8 1:1 macro lens.

The Lumix X 12-35mm f/2.8 also has some minor disturbance in the border: The out-of-focus highlights are rendered somewhat non-circular. When stopping down, this becomes less of a problem. However, this is a very minor issue.

Overall, I think the Sigma 19mm f/2.8 EX DN probably has the most pleasing out of focus rendering in this high contrast scene.

New Panasonic kit zoom lens

2013-01-29T19:22:00.002Z

Today, a new Panasonic Lumix kit zoom lens was announced. This doesn't look like a very interesting lens for seasoned Micro Four Thirds users, as it has the rather boring specifications 14-42mm f/3.5-5.6. Panasonic has already released three lenses with similar specifications, so why make one more?

Lumix G 14-42mm f/3.5-5.6 released in 2013

Here are two of the previous lenses:

Lumix X PZ 14-42mm f/3.5-5.6, Lumix G 14-42mm f/3.5-5.6

Lumix Lens	G 14-45mm	G 14-42mm	X PZ 14-42mm	G 14-42 II
Year released	2008	2010	2011	2013
Diameter	60mm	61mm	61mm	56mm
Length	60mm	64mm	27mm	49mm
Weight	195g	165g	95g	110g
Filter thread	52mm	52mm	37mm	46mm
Front lens diameter*	45mm	30mm	21mm	25mm

*) The front lens diameter is not stated in the lens specifications, but is based on my own measurements, supplemented with inspections of product photos.

I'm guessing that the new lens will replace the 2010 Lumix G 14-42mm f/3.5-5.6 kit zoom lens. It makes no sense to replace the Lumix X PZ 14-42mm f/3.5-5.6 pancake lens, since Panasonic needs this one to compete with a similar lens from the Sony NEX system, the Sony 16-50mm f/3.5-5.6 pancake zoom lens.

When looking at this table, it is quite clear why Panasonic is replacing the 2010 zoom lens. The new lens is smaller, and lighter. It probably uses a plastic lens mount, which I see as no problem for such a small lens.

The compactness is an important selling argument for Micro Four Thirds lenses. With smaller and smaller competitors, Panasonic must step up and make even smaller stuff, to stay competitive. The old kit zoom lens was not as compact, and hence, not attractive enough for the market.

The new lens appears to be the type which is the most compact at the centre of the zoom range, unlike the older Lumix G 14-42mm, but like APS-C tele zoom lenses.

Another observation is that the front lens element is smaller than that of the 2010 14-42mm lens, but larger than that of the pancake powerzoom 14-42mm lens. The pancake zoom lens achieves the small front lens element by sacrificing aperture speed in the middle of the zoom focal range. Here is a diagram illustrating the aperture as a function of the focal length for the two lenses:

The Lumix X PZ 45-175mm also achieves a smaller front lens element in the same way. Read about it here. With this in mind, I'm guessing the new lens will have an aperture range somewhere between the two lenses above. One could say that this is a form of cheating: Panasonic achieves a more compact lens by lessening the specifications in a way which is not visible in the lens name: The aperture end points are still f/3.5-5.6.

As for the finish of the new lens, it has the new glossy appearance. I'm not too happy with this, as I prefer lenses to be matte and non-obtrusive. But it appears that glossy is what the market demands at this time.

Other lens news

Incidentally, other lens news also fall into the same category: Remakes of existing lenses.

Olympus has launched an updated version of the Olympus M.Zuiko ED 75-300mm f4.8-6.7. The new version has a new design, better matching the Olympus OM-D E-M5 camera, and also a new lens coating. But the lens is essentially the same. The good news, though, is that the price has decreased significantly.

Olympus M.Zuiko ED 75-300mm f4.8-6.7 II Lens

Sigma has updated their Micro Four Thirds prime lenses. The new lenses appear to have exactly the same optical design, but have a new lens barrel design. In what appears to be a strange design choice, the ribbed plastic focus ring of the original lenses has been replaced with smooth metal rings. From an ergonomic point of view, it is hard to see how this is good news. I'm guessing this was done to make the lenses look more expensive, and to motivate a higher retail price. They are part of Sigma's "Art" line of lenses.


Sigma 19mm f/2.8 EX DN	Sigma 19mm f/2.8 EX DN updated

Sigma 30mm f/2.8 EX DN	Sigma 30mm f/2.8 EX DN updated

Sigma also launched a new lens, the Sigma 60mm f/2.8 EX DN. This lens is a completely new design, and unlike the Olympus lens with similar focal length and aperture, this one is not a macro lens:

Sigma 60mm f/2.8 EX DN

Sigma 19mm autofocus comparison

2013-01-27T13:04:00.001Z

The Sigma 19mm f/2.8 EX DN is perhaps a strange lens. In terms of specifications, it is quite close to the Lumix G 20mm f/1.7 pancake lens, except that it is slower, and less compact. So, why would anyone be interested in it?

Lately, it sells at a reasonable price, and besides, it features the normal internal focus system, while the Lumix G 20mm has an old style focus mechanism which moves all the lens elements, being slow and noisy.

I have found that the Sigma 19mm lens is slightly less sharp than the Lumix 20mm lens, at similar apertures. This is consistent with other people's findings.

With still images

What about the autofocus performance, then? Is it faster, as one could guess? Here is a comparison where I put both lenses on the Panasonic GH2, and focused down to around 0.3m:

The Sigma 19mm lens spends 0.28s focusing down to close to the minimum focus distance, while the Lumix 20mm lens needs 0.64s. So the Sigma lens is indeed faster, as we had expected in advance.

During video recording

Another important aspect is continuous autofocus during video. This is still the achilles' heel of the Micro Four Thirds system, and not even the most recent cameras do this well.

To test it, I mounted the Panasonic GH2 with the Lumix G 20mm f/1.7 lens to a wooden plank, and next to it, mounted the Panasonic GF3 camera with the Sigma 19mm f/2.8 lens. I used Manfrotto Superclamps to mount the cameras, just like when I tested the rolling shutter properties of the GH2 and GH3. I set both lenses to f/2.8 for similar depth of focus properties.

Of course, the 19mm lens has a wider field of view. But on the other hand, the GH2 has the multi aspect sensor, oversized sensor property, which gives relatively wider field of view in video compared with the non-multi aspect sensor GF3 camera. So the field of view is probably quite similar for the two cameras.

Here are the two video footages, combined to one clip. To see the focus performance, it is best to view this in 1080p, click on the youtube icon to access this possibility.

The results are not completely consistent, but I think the Sigma 19mm lens and GF3 combo keeps the focus better during the video. One could speculate that the GH2 probably has the better image processing technology, and hence, should have the advantage in terms of handling continuous autofocus. Despite the handicap of being combined with the basic GF3, the Sigma lens performs better.

It would have been better to mount the lenses to the same camera, of course, but I don't have two of the same camera model. Also, I would normally have used the newer GH3 camera, but my camera is sent back for repair. I hope I get it back soon, and that I don't have to wait for three months, like I had to when sending back the Lumix G 14-42mm lens for misaligned aperture diaphragm blades.

Conclusion

What this shows, is that the Sigma 19mm f/2.8 EX DN lens is better for video use, as long as you can live with the f/2.8 aperture. While it is not as sharp as the Lumix G 20mm lens, it is still very sharp, and certainly more than sharp enough for video use. The autofocus is also less audible.

Even if the Sigma 19mm lens is larger, it is still quite non-obtrusive, with a matte black finish.

The Lumix G 20mm f/1.7 pancake lens is a classic Micro Four Thirds lens, praised for the very good sharpness. However, people also find it annoying for the slow and noisy autofocus performance. People have also reported that the focus mechanism can be clogged with dust, due to the moving front elements. The Sigma lens has no moving lens elements on the outside (only internally), and is probably more solid in that way.

Given the low price the Sigma 19mm f/2.8 EX DN sells at, it can be considered a good value for money, and an interesting alternative to the Lumix G 20mm f/1.7.

I haven't tested the "brother" lens, the Sigma 30mm f/2.8 EX DN in the same way, but I would guess that it, too, performs well in terms of autofocus speed.

GH3 rolling shutter examples

2013-01-25T19:06:00.001Z

The Panasonic GH3 has a very useful feature, the electronic shutter. One disadvantage of the function is that it suffers from quite severe rolling shutter artefacts. Read more about it here.

Here are some example images, taken with the electronic shutter, the mechanical shutter, and a still image from the video output:

Electronic shutter (f/1.7, 1/250s, ISO 200):

Mechanical shutter (f/1.7, 1/250s, ISO 200):

Video still image:

We see that the electronic shutter has a slower sequential readout than the video mode. This is unlike the Panasonic GH2, which used the video output for the electronic shutter mode, and they shared the same rolling shutter properties. But then again, you only got a 4MP image with the GH2 electronic shutter mode, and it was quite unsharp, probably scaled up from 1080 lines or thereabouts.

This will be my last Panasonic GH3 related article for a while, and the review I am writing will be delayed. The reason is that I have delivered the camera for a warranty repair: The automatic switching between the LCD and EVF suddenly stopped working.

My GH1 and GH2 have operated flawlessly for years. It is perhaps ironic that the GH3 was my first Panasonic camera to require a repair, since it is marketed as being extra solid and weather proof.

The last time I had a Panasonic item for repair, due to uneven aperture diaphragm blades, they kept the lens for three months. And when I did hear from them, they just gave me a brand new lens, which turned out to exhibit exactly the same problem.

I'm hoping they don't keep my GH3 for as long.