DSLR 3D stereoscopic filming with GH13s and other tricks

More details on the small 3D beam splitter rig

2010-12-17T13:52:00.000-08:00

The small beam splitter with a couple of hacked GH13s

It seems the beam splitter I designed generated more interest than I initially imagined, so here is some more info on how I built it, but before I´d like to mention a few things, such as why I decided to built this rig in the first place. I am a director and film maker by trade, I have shot commercials, music videos and documentaries with all sorts of sets ups and cameras from Sony´s F35, Red, 16mm film and 5D mk2, as well as a recent project in 3D: a commercial for a German bank´s charity, for Cinema release. The rig was from P&S technik if I remember well, we used a couple of Sony 900, the rig weighted well over MY OWN weight, it needed 3 guys to pass it from dolly to tripod.

Versus the standard size 3D beamsplitter we used...

I wanted to have a 3D rig that could be hand-held, similar in some respect to the DSLR revolution, small, compact and enabling me to shoot easily wherever I wanted without the need of a crew to lug the gear around, pull focus, and so on. Imagine that at any time during that shoot, there was around the camera, at least the director (me), the DP, the stereographer, the camera assist, and fortunately no additional focus puller, but still 4 guys stuffed around that rig at all time (check the making of on www.bastienfrancois.com/3d/).

When building the beamsplitter, what I wanted to achieve was a rig with the smallest footprint possible, with proper image quality. I am not yet totally happy with the results, but I am getting there. I am thinking of adding a 3D field monitor (bit heavy) or possibly pluging a pair of those LCD 3D glasses instead, so as to be able to check depth while shooting. The rig weight about 4kg, (that´s about the weight of a normal professional camcorder like the HVX 200) which is, as far as I know, the lightest rig with broadcast quality image output.

It took me a while before getting to build the rig, first trying to find technicians to help me, or build it for me, and after not finding anyone ready to help, wondering if I was up to the task myself. I am a pretty handy person, I have a few tools but then iron, drills and screws are not much part of my trade. I finally layed a basic blue print: the concept is in itself very simple really, but the devil is in the details. I bought the mirror online (it took me a while to find the right size as custom made mirrors are really expensive), I went to see a local company that builds aluminium window frames, and asked them to cut me a few pieces according to my specs.

The blue print was essential in getting the placement of the cameras correct, one of the most important things I´d say was to get the lenses as close to the mirror as possible so the least "amount of mirror" is needed for each camera, so as to maximise the useful interaxial distance of the rig. Let me remind you that the whole point for me was to build the smallest beam splitter possible, since after 10cm of parallax distance, it becomes much easier to shoot parallel (basically beamspiltters are a pain, side by side is MUCH easier, more about that in a moment).
The whole point of a beam splitter is to be ablevto shoot 3D close-ups that you would´nt be able to shoot side by side due to the size of the camera. All I needed was a beamspiltter to accomodate the GH13 (in itself one of the most powerful camera around) for smaller interaxial distance.

The main problem with this rig is that it is VERY basic, so aligning the cameras can be a pain, I can change the placement of the upper camera for interaxial distance unscrewing and re-screwing at the right distance. I needed as well the possibility to accommodate two (very) different lenses, namely the stock 15/150mm and the 20mm, which are at oposites in terms of size. the 20mm is about 2cm thick, the 150 is a good 10 cm long, and weight 4 times as much, both are fantastic lenses. I have a pair of zeiss FD 55 too, but I don´t bother much with them. I decided to stick to Panny lenses that offered me AF, since I´d be shooting quite a bit hand-held and moving around, and certainly without a focus puller to assist, what´s with the additional remote focus gear on the rig. Since the lenses are not synced, sometimes there are focus discrepancies (especially with the extremely slow focus of the 20mm lens) which obviously mess up the shot. I would usually shoot more takes of the same shot because of that.

I am well aware that the guys at 3Dvision have spent quite some energy trying to sync both cameras perfectly, but there solution is too cumbersome for me, and I have found out that with a simple dual remote shutter, the sync problem was never more than 8/1000th of a second when shooting 50p, which is perfectly reasonable in most cases, except when there is loads of camera movements (not advisable in 3D in anyway).

The first results where horrendous, I have to admit, I spent quite many hours half sick in front of the 3D screen, and that is certainly not a feeling you wan tot inflict to your audience. It took me a while to nail down all the little details, such as the best depth of field and focus strategy, adding barn doors because flares on the mirror where a disaster.

The thing is beam splitters are a transition tool, until small enough cameras at reasonable prices are available to get rid of beamsplitters altogether, they are a pain in the bum to calibrate, the mirror will eat your light (2 or 3 stops) and bring color shifts between cameras, it is one more surface/lens to keep really clean, bigger mirrors introduce yet more problems because the glass is never absolutely flat and bends slightly because of gravity, therefore squashing your view, which introduces more corrections in post, etc, etc. It is MUCH easier to shoot side by side, simple. Very efficient cameras are getting smaller all the times, and (shallow) depth of focus is not so much an issue in 3D, so bigger lenses/sensors are not so important. Most likely we wont hear of beamsplitters in five years except for macro really. My own two cents.

On this blog you´ll be able to see some demos and tests made with the rig, you can also have a look here at my own site for more stuff: www.bastienfrancois.com/3d/,(remove the /3d/ to see the 2d stuff) I hope you find this as interesting as I did building and experimenting with the rig, and please, leave some comments, let me know what you think of the results achieved.

Interesting rig side-by-side nikon based 3D rig...

2010-12-02T15:52:00.000-08:00

An interesting picture has emerged of a Nikon based 3D rig, which was used during the Tour de France, I have been trying to gather some info about it without much success. Looks like the left camera is upside down, presumably to reduce the interocular distance, it seems both zooms are paired through an arm linking them. Still looking for infos.

Autostereoscopic displays right round the corner?

2010-11-28T13:29:00.000-08:00

As reported on Stereoscopy.com: iPONT International, a creator, converter and distributor of glasses-free 3D, and Palace Cinemas, the largest cinema chain in Hungary, will screen 3D movie trailers without the need for 3D glasses - giving movie-goers the first-ever opportunity to preview movies in 3D while in the lobby. Theywill be able to see autostereoscopic movie trailers on a 65-inch 3D display.
Based in Budapest, Hungary, iPont International (http://www.ipont.eu/) specializes in the creation, conversation and distribution of 3D content.

panasonic´s 3DA1 versus a beamsplitter and a couple of gh13s

2010-11-28T05:30:00.000-08:00

That camera is definitely quite a nice bit of kit, but it is certainly not worth the huge amount of money they ask. Filming with a couple of hacked gh13s on a beamsplitter, I can change the interocular distance (the 3DA1 can´t), shoot 50fps in 720p (the 3DA1 can´t as far as I know) up to 80mbps, color space 422 when shooting mjpg (3DA1 is 420 therefore not broadcast compliant for many 3D channels). I can change lenses, have shallow depth of focus if I want to (shallow DOF can be awsome in 3D as well), the rig can be handheld, barely weighting more than the 3DA1, and , oh! it cost me a quarter of the price of the 3DA1. It looks like the 3DA1 interocular distance is about 5or 6cm, there is basically a "sweet point" distance of 1m tp 1, 50 at which the 3D effect works best, closer and you´´ll induce headaches to your audience, further and the 3D effect will rapidly fade.

Promotional 3D film of Ibiza shot with the small beam splitter

2010-11-26T13:33:00.000-08:00

Extract of a promotional 3D film for Ibiza which I shot with the beamsplitter I designed, to be used by the tourism board of Ibiza and a local production company with whom I work regularly.

Making of Deutsche Bank Skyliners 3D commercial directed by Bastien...

2010-11-26T06:01:00.000-08:00

This is the making of the the 3D commercial I directed in May 2010 for Deutsche Bank Skyliners (through Neue Sentimental Frankfurt), you can see the commercial in an earlier post (below). As you can see the rig is huge, it could barely enter the cubicles where I had to film the kid, which obviously limited enormously what and how we could shoot. This is partly the reason why I decided to design the smallest 3D rig possible, using a couple of hacked Gh1s.

Interesting system from SinaCam:

2010-11-24T07:16:00.000-08:00

this system is probably one of the most promising I have seen around for a while, tiny but with proper HD specs, and small enough to eliminate the need of a beamsplitter for most shots, this is pretty much the future of 3D filming:

Consisting of a couple of 2/3“ CCD Sensor 1920×1080 Pixel, 10 Lux/F2.2 Sensitivity, shooting 1920×1080, 1440×1080, 1280×720 interlaced and progressive up to 60 fps, Output Interfaces up to 2x dual HD-SDI with optional Memory Card Module for high speed H.264 recording. With that type of small cameras, the interaxial distance could be reduced to 41 mm (width of the camera), which would allow for close ups down to 120cm or so, close enough not to need a beamsplitter for most shots, exept extreme close ups.

I would love to know the price of this little wonder.

3D camera from Sony...

2010-11-24T06:52:00.000-08:00

Interesting video from diginfonews japan about Sony´s latest 3D camera prototype, not much more info for the moment, no specs released yet:
The shoulder mount 3D ENG Production prototype camera has four SxS memory slots, both left and right channel HD-SDI outputs, a dial for adjusting convergence. It is believed the Sony ENG twin lens 3D camera will be released in 2011... price? well my guess is north of 25k, if they adjust to Panasonic´s pricetag for their 3D camcorder.

Dual remote shutter finally here.

2010-11-24T06:27:00.000-08:00

I finally got my hands on a working dual remote shutter (it took me months) for the GH1s, through a company in Japan which was recommended to me by (the now quite notorious) Inouek3D, with whom I have regular email exchanges regarding his experiments in 3D with GH1s. According to inouek3D, using the dual shutter trigger gets the time discrepancy between cameras down to 4 ms when shooting 50P.

Second demo using the small beamsplitter

2010-11-03T09:13:00.000-07:00

Here is a second demo using the small beam-splitter, (do look at the video on Youtube directly for the yt3d tag to be enabled). I had to do a video for a label I´ll hide the name for now, for their in-store screens, I shot part of it in 3D: We had a Great location, perfect light, gorgeous models, it would have been a shame not to give it a go. I am getting a better grip at it and managed to get quite a few more valid shots compared to my first trials, despite the fact that both cameras are still not synched. I wont deny that some of the shots might induce headaches, but is it due to cameras´s synching or to too much movement, or too strong a parallax? (parallax was 4cm for most of those shots, hence the girls close-ups a bit hard on the eye, I should have stayed at 120 cm minimum.) I´ll let you guys be judge of the results. Let me know what you think.

Updated version of the gh13 beam splitter rig

2010-11-02T15:24:00.000-07:00

Here is a photo of the updated rig, with french flag and doors. One of the main trouble I had previously was light reflections in the mirror, giving flares in one of the camera but not the other. I (partially) solved the problem now:
Footage become easier to grade as the beam splitter mirror gave a slight tint when hit by too much light. the rig is still just about 4 or 5 kgs (9 lbs all in all, making it easy to use handheld). i still haven´t found a good way to synch the cameras, I do that in post. I shoot 720 50p to reduce the frame discrepency to a minimum.

Here is a side view of the rig with doors and french flags, with my lovely (bit messy tho!) garden behind. Hoping to post some more 3D footage very soon.

2010-10-15T14:51:00.000-07:00

Here are a few pictures of the making of the 3D commercial for Deutsche Bank Skyliners, if you want to see the video making of, please go to www.bastienfrancois.com/3d/

One of Germany´s first 3D commercial, directed by Bastien Francois for Deutshe Bank Skyliners on rotation on German TV as well as in 3D cinemas

2010-10-15T14:22:00.000-07:00

Please go directly to Youtube to watch the spot in 3D as the "Y3d" tag is not suppoted in embeds.

Press Release (June 2010)

James Cameron´s epic tale “Avatar” has jumpstarted the 3D revolution, and now all major TV and computer manufacturer are offering 3D unabled TV sets, 3D blue-rays players, laptops and computers. Neue Sentiumental Frankfurt is now the first production company to have realised a 3D stereoscopic commecial: a 40 seconds spot for cinema release, and a slightly shortened version in 2D for distribution via TV have been created.

Besides the technical prowess of it all, the spot´s concept comes from the creative agency Leich + Frei: the film promotes the initiative of "Basketball in Schools" by DEUTSCHE BANK SKYLINERS*, whose goal is to promote basketball to children of defavorised milieuxs prone to drugs consumption..

Dr. Gunnar Wöbke, second vice-director of the DEUTSHE BANK SKYLINERS Frankfurt "would like to thank the advertising agency Lesch + Frei, Neue Sentimental Film and ACHT FRANKFURT for their generous commitment and great work, and agreed that the spot would help their "basketball in schools" initiative.

Neue Sentimental Film specifically assembled for the spot an international production team, helmed by the Belgian director Bastien Francois, and composed of London based sound designer Tim Harrison, and Berlin based composer Xavier of Treyer. The 2D and 3D post-production was realised by post-production house Die Acht FRANKFURT and sound and dolby mixing was done by the local recording studios Pearls and FunDeMental.

Tom Glaeser, executive producer and director of Neue Sentimental Film Frankfurt GmbH said: "We wanted to achieve optimum results for this film and have therefore opted to have much more elaborate production values and, on the advice of Director Bastien Francois, we decided to complete the entire film in stereoscopic 3D, in order to reach our younger audience in 3D cinemas, and get them excited about the `basketball for all` initiative. "

The Film is currently shown in 3D cinemas across Germany, a standard version is shown across different german TV networks as well.

More information is available at:
http://www.dbsf-ev.de/ (DE)
http://www.wuv.de (DE)

Pictures of the first stages of the mini 3D rig

2010-10-11T16:37:00.000-07:00

So here are a few pictures of the rig as it was when I shot most of the stuff in the clip in the previous post. As you can see it is tiny, it weights about 2.5 kgs or 5lbs I´d say, which is pretty much like a handheld camcorder, but it is not very stable, even if well balanced, with the handles on each side (you can notice that in the clip.

Setting up the parallax takes me some time, I have put marks at positions I use most. I pretty much set the rig with the lenses, choose a parallax distance, and do all my shot in accordance: (ie: the distance at which I´ll keep my subject(s) at...)

Fisrt 3D stereoscopic tests using a small beam splitter rig with a couple of GH13s

2010-10-11T13:00:00.000-07:00

Please double-click on the video to go to Youtube and see it in all its stereoscopic glory after yo u have read the following lines. the Y3D Youtube stereoscopic tag does not work with embeds.

This is the first "more or less" conclusive results of a small stereoscopic 3D beam splitter rig I put together using a couple of hacked Lumix GH1s, shooting 720 at 50fps in order to reduce the amount of synch problem between cameras. Parallax distance varies in different shots, but is between 18 mm to 70 mm, for greater parallax distance I can mount the cameras side by side, shooting parallel, no convergence.

Post done with various solutions, from the free Make3D plugin for Sony Vegas to the very impressive and free Stereomovie maker to the trial of the very expensive Cineform Neo HD suites.

The whole experience was a bit of a test to get footage, process it and broadcast it online on a super tight budget. I have shot stuff with the P&S technik beamsplitter and a couple of sony 900, a rig that needed 3 guys to move around. Put on a Dolly it looked like a tank, we could barely pass doors. It took weeks to get a 30 sec spot out, least of all because we had to figure out the whole post workflow.

I wanted to find a way to do handheld stuff, rapid (I do a lot of documentary run.and-gun styles stuff) using super small self designed rig, and a custom made laptop with 3D screen, Nvidia GTX 285, 3D glasses and off-the-shelve, free or open-source software. It took me a while to get the first results out but now things are speeding up.

Because most of the stuff is handheld and I don't have a focus puller nor remote focus gear, I relied on the auto focus of the lenses: 2 pancake 20mm or 2 stock 15-150mm. The focus disparity messes up some shots obviously, the fact that both cameras are not synced messes some more, but it is trial and error, and some good stuff comes up. You´ll realise by yourself watching this clip, some shots work really well, some other makes you feel sick straight away.