Photography

Understanding Shutter Delay in Digital Cameras

2007-11-09T23:35:00.001-08:00

When using a digital camera to take action photos you will notice that there is a delay between the time you press the shutter button to the time the camera actually takes the photo. In most cases this delay is small enough and not noticeable but when taking action photos, when trying to capture an event that just happened or when trying to capture a moving object this delay can result in a photo that just missed the action. In this article you will better understand what causes the shutter delay and how you can overcome it.

A shutter delay is defined as the time gap between pressing the shutter button to the camera actually capturing the photo. There is no shutter delay in film cameras as in these cameras the shutter button is virtually connected to the shutter itself and holding down the button results in the camera taking a photo immediately. In digital cameras the shutter button is connected to a built-in micro computer and holding down the shutter button initiates a series of events that result in capturing a photo.

When you press the shutter button the camera goes through a series of setup events in order to get all its electronics ready. Only when these events are finished can the camera capture the photo. The time it takes for the camera to complete these events can vary but is usually around one second or so. When taking subsequent photos there is an addition delay as a result of the camera compressing the photo and writing it to the slow flash memory.

Although a circa one second delay does not seem long it can make the difference between capturing an action photo to missing it. Some cameras will also initiate a focus process when the shutter button is held down and will only take the photo when the focus is completed. This can add even more delay.

Although it is impossible to remove the shutter delay in your camera there are few practices that can help avoiding its results. For example many cameras include a burst mode. In burst mode the camera shoots a fast series of photos for as long as the shutter button is held down or until the camera’s memory is full. In this mode the camera writes the photos to a temporary memory which is very fast but small. When the shutter button is released or the memory is full the camera starts the slow process of writing the photos to the flash memory.

Using the burst mode you can shoot fast photos of an action event and then choose the one that best captured the events. The speed and the amount of photos that the burst mode supports vary between cameras. Some high end cameras can take as much as ten photos over the course of one second.

Another delay that is a result of the digital camera technology is the Initial Delay. Most cameras will enter into a standby mode if not used for a certain amount of time. This time can vary but it’s usually in the few minutes range. When the camera goes into standby mode it turns off most of its electronics in order to save power. Usually pressing the shutter button will restart the camera but such a restart process is long and can take a few seconds. The result is a longer delay when taking a photo after the camera was idle for some time. In order to avoid this you would have to make sure that your camera is turned on and does not go into standby mode when taking action photos. Some cameras allow you to disable the automatic standby feature through a menu option. If your camera does not allow that you can keep it on by pressing the shutter button half way down every now and then. The downside of leaving the camera on all the time is wasting battery power. In order to maximize battery life in such scenarios you can disable the camera’s LCD screen which consumes a lot of energy and use the view finder instead.

Another way to minimize the shutter delay is to avoid the automatic focus process which usually starts when the shutter button is held down. One way to do that is to hold the shutter button half way down. In most cameras the result will be a one time focus process and then a focus lock. The camera will stay in focus and when the shutter is fully pressed it will take a photo without re-focusing. Another option is to put the camera in manual focus.

It takes practice to get to know your camera and to get a feeling of the delays it introduces. Although there is no way to completely get rid of the delays you can master overcoming them by practicing taking action photos. New high end professional cameras have a very short delay and as the electronics improve cameras will eliminate the shutter delay altogether.

Ziv Haparnas writes about science and technology. This article can be reprinted only if the resource box including the backlink is included. Information about photography and photo prints is on printrates.com - your home for digital photo printing Ziv Haparnas is a technology expoert.
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Ziv Haparnas

Pros and Cons of Battery Technologies Used in Cameras – Choose the Right One for You

2007-11-09T23:33:00.000-08:00

Like other portable consumer electronic devices digital cameras use batteries as their power source. In this article we will describe different battery technologies and their cons and pros. Armed with this knowledge you will be able to take into consideration the battery used when purchasing your next camera.

A camera usually supports just one type of battery either a disposable battery or a rechargeable one. The exception is cameras that are powered by standard AA, AAA or similar batteries. In most of these cases disposable and rechargeable batteries can be used interchangeably.

There are two battery types:

disposable batteries: can only be used once. They usually have a standard size and shape such as AA, AAA and so on. You can buy these batteries at most stores and once they are empty you simply dispose them (please help keep the environment safe and clean by disposing batteries only to special battery disposal containers).

rechargeable batteries: can be used multiple times. Some rechargeable batteries have a standard size and shape such as AA, AAA and so on. Such standard size batteries can be used anywhere that a disposable battery can. More often than not however rechargeable batteries have a proprietary shape and are compatible with just a few specific cameras. Once a rechargeable battery is empty you can place it in a special charger that will recharge it. The time it takes to recharge a battery, the number of times it can be charged and the life time of the battery are dependant on the technology used to build the battery.

There are pros and cons to using disposable or rechargeable batteries. The main advantage to using a disposable battery is that you can always buy a few to have with you to replace the ones that are empty and you can always get one in a store close-by in case you are stuck with empty batteries. The disadvantages to using disposable batteries are the cost of buying new batteries every times your batteries are empty, the capacity (in most cases a disposable battery will not last as long as a good rechargeable battery). On the other hand rechargeable batteries require only one purchase. When the battery is empty you can simply place it in its charger and after an hour or so you will have a fully recharged battery. The disadvantage is that if you run out of batteries during a photo shooting session or somewhere away from home or a power supply you can not just buy another battery. The solution to that problem is to buy one extra battery and to always carry it with you fully charged.

If your camera uses standard size batteries such as AA or AAA you can have the advantages of both disposable and rechargeable batteries. You can always use disposable AA or AAA batteries with the camera but you can also get a rechargeable AA or AAA battery and use it when convenient.

Rechargeable batteries technologies:

Different technologies are used in building rechargeable batteries. Look at the battery itself to find out what technology was used in most cases it will be written on a small sticker on the battery or somewhere on its packaging. The following are the most common technologies and some of their pros and cons:

nickel cadium: one of the oldest technologies. These batteries are inexpensive, they can be recharged fast and many times before they lose their capacity. On the downside they have a low capacity and have a “memory effect” – a “memory effect” means that the battery can not be recharged to its full capacity unless it is first fully discharged. This can be problem since in most cases you will want to make sure your battery regardless of its current state is fully charged before going on a photo shooting session. Some charges solve this problem by first discharging the battery and only then recharging it to its full capacity.

nickel metal hybrid: this technology is an improvement of nickel cadium. These batteries capacity is much higher up to 50% more. Although it still has a “memory effect” it is less noticeable than in nickel cadium batteries. On the downside these batteries can be charged less times before losing their capacity and they also discharge faster when not in use.

lithium ion: A new technology that solves many of the nickel technology problems. Lithium ion batteries have a higher capacity than even nickel metal. They have no “memory effect” at all (and thus regardless of their current state they can always be recharged to their fullest capacity). The downside is that they are more expensive than nickel batteries.

lithium polymer: the latest technology. These batteries have all the advantages of lithium ion and more. They have an even higher capacity and can also be easily manufactured in any shape or form. This allows for much smaller and lighter high capacity batteries and for batteries shaped to better fit the camera design.

In conclusion when choosing a camera and considering what batteries it uses you should first make a choice between disposable and rechargeable batteries. If you choose to get a camera that uses rechargeable batteries you should try to choose a battery that uses the latest technologies like polymer or lithium unless you have some special considerations.

Mr. Haparnas writes about practical technology and science issues. You can find more information on digital photo printing printing and photography in general on printrates.com - a site dedicated to digital prints Ziv Haparnas is a technology expoert. This article can be published and used as long as the resource box including the backlink is included.

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Ziv Haparnas

How Does the Camera Auto Focus Work and Why Sometimes It Fails?

2007-11-09T23:32:00.000-08:00

How does auto-focus work?

All of us use it every time we click on the shutter button. Practically all modern cameras include some sort of an auto focus system. Thanks to the auto focus system we can enjoy an easier photography experience and can concentrate on composing the right photo and capturing the moment rather than on manually setting the focus.

Automatic focus though has its limitations. For example sometimes one might want to produce photos which are a bit fuzzy as an artistic expression. Also the auto focus implementation has its limitations and in some scenarios it might fail. One example is using a high end SLR camera with a passive auto focus system to take a picture of blue skies. In most cases the camera will move its motor back and forth and will eventually give up and fail to focus.

To better use the auto focus system it would help to understand high it actually works. Although implementations can vary we can divide them all into two categories: passive and active. Most pocket cameras use the cheaper passive method while high end professional cameras use either the active or a combination of both.

Passive auto focus:

Passive auto focus can be perceived as imitating how we set the focus manually. The camera defines one or more regions in the picture (usually they are marked as rectangles on the viewfinder or the LCD). The camera then analyzes the picture seen through those regions and calculates a Focus Level number. The camera then tries to move its lenses back and forth as it recalculates the Focus Level. The camera looks for a position where the Focus Level is the highest. For that point if the Focus Level is above a predefined threshold the camera would define this region of the photo as being in focus.

The Focus Level can be calculated in many ways. The common attribute of all calculations is figuring out how much Contrast is there in the photo. Although not in the scope of this article one way to calculate such a number is by running the photo through a high frequency filter – this is based on the fact that high contrast is associated with high frequencies.

Active auto focus:

Active auto focus works by measuring the distance between the camera and the object in the picture. Technically if you knew the exact distance to the object you are taking a picture of you could set the lens to the exact focus position. The active focus system shoots a beam of invisible light, usually infrared, at the object at the center of the picture and measures the distance to that object. Based on that distance the focus is set.

Combined auto focus:

Some high end cameras combine both systems. The camera will pick the right system for the specific scenario or will cross check and use both at the same time. The photographer can also decide manually to use one of the two options. For example when shooting blue skies the camera can try to use the active system and measure the distance. Since the distance is infinite the camera can set the focus and skip the passive focus. In other cases when the distance is not infinite the camera can use the active system to put the lens in approximately the right position and then use the passive system for fine tuning. In dark scenarios the camera can opt to use the active system since the passive one will not work.

So why doesn’t the auto focus work all the time?

Even with all the electronics and computing power in the camera there will always be scenarios where the camera auto focus fails. Failure can be when the camera can not focus and the picture is fuzzy or sometimes when the picture is actually in focus but the camera “thinks” that it is not.

What causes such cases? The list is long but here are just a few examples:

- Taking low light pictures: The passive auto focus system needs to “see” the picture in order to work and in low light scenarios this is not possible. Some systems use a series of flashes to overcome this limitation but this solution fails many times. An active system can measure the distance to the object in such scenarios but will fail if the object is not in the center of the picture or if there are a few objects at different distances.

- Active systems can fail with objects that tend to absorb the infrared beam they are using. Some materials absorb infrared beams and will cause the active system to measure the wrong distance. In some scenarios other infrared sources such as candles and open flame fires can render the active system useless.

- Low contrast objects such as white walls or blue skies. The passive auto focus relies on the fact that the Focus Level changes significantly when moving the lens back and forth. This allows the camera to settle on the right focus position. The Focus Level of low contrast objects does not change much and fails the passive system.

Knowing how the auto focus system works helps a photographer understand why sometimes the camera can not focus. In such scenarios the photographer can look for other solutions. Sometimes the photographer will have to use the manual focus. In other cases focusing on another object in the picture that is in the same distance but easier to focus on and locking the focus on that object will solve the problem.

This article can be reprinted and used as long as the resource box including the backlink is included. Ziv Haparnas is an expert technology writer. You can find more information on digital photo printing printing and photography in general on printrates.com - a site dedicated to photo printing Mr. Haparnas writes about technology and digital photography.
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Ziv Haparnas

How to choose a camera with the right number of Mega Pixels?

2007-11-09T23:31:00.000-08:00

The race for mega pixels has started and there is no way to stop it. Every few months cameras with more pixels hit the market. The manufacturers want you to dump your old camera and buy the newest and greatest one after all aren’t 10 mega pixels better than just 8? Apparently the answer is not that simple.

As with many other things when it comes to mega pixels more is not necessarily better. There are many considerations when buying a camera and the number of mega pixels is just one of them.
One of the most important things to consider is usage. More mega pixels are good for people who plan to print photos (especially enlargements) or for people who need to zoom in and grab fine details from a big photo. If the main usage of the photos is watching them on your computer screen and maybe printing a few 4X6 prints than 2 mega pixels is more than enough (yes… just 2). Most screen resolutions are 1024X768 so even when viewing the photo in full screen mode you can only view 1024X768 < 1 mega pixels. A 2 mega pixels 4X6 photo print will have a DPI higher than 300 which is more than enough for a good quality print.

If you plan to use your photos for enlargements than a rule of thumb is to be able to print at least 300DPI resolution. The following is a table for different print sizes and the needed mega pixels for such print quality:

page 4X6 2MP
page 5X7 3MP
page 8X10 7MP
page 11X14 14MP
page 16X20 28MP
page 20X30 54MP

Another practical consideration is price and budget: Usually the more mega pixels the more expensive the camera is. Unless your budget is infinite when buying a camera you make a compromise between mega pixels and other features. For example is it better to spend money on more mega pixels or on better lenses? Or maybe instead of getting the latest number of mega pixels get an external flash for low light photography? When buying a camera try to predict what and how you will use it. In many cases a lower mega pixels sensor with better a lens will result in a much better photo than a high mega pixels with an inferior lens. Shop around and make sure that you get the best package in terms of mega pixels and other features.

To conclude when shopping for a camera it is best not to be a victim of the mega pixels race. Although it is generally a good thing to have a high number of pixels there are many other factors that influence the quality of the photos taken and the choice of the right camera for you. Lenses, battery life, light sensitivity, sensor technology used, external flash and many other features are not less important as the number of mega pixels. When shopping for a camera make sure that you consider the whole package and not use the number of mega pixels as a “quality” indicator for your buy.

Ziv Haparnas is an expert technology writer. More information on digital photo printing and photography is available on printrates.com - a site about digital photo printing This article can be reprinted and used as long as the resource box including the backlink is included. Ziv Haparnas writes about science and technology.
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Ziv Haparnas

Scanning paper prints to digital photos on your hard disk

2007-11-09T23:30:00.002-08:00

Sometimes you find yourself in a situation when you have to scan paper prints, negatives or slides and store them as digital photos on your computer. Although the reason for doing that can vary there are some common considerations to scanning paper prints. In this article we will go over some of them and try to make your scanning experience easier.

There are three types of prints that you might be scanning:

Paper prints: the most common, usually at sizes like 4X6 and 5X7.

Negatives: also known simply as film. This is the processed film usually 35mm from which paper prints are made.

Slides: very similar to negatives used for projecting photos on a large screen.

Scanning paper photos prints.

Photo paper prints are easy to scan. You can choose to scan them yourself at home (purchasing a scanner that can do the job is usually cheap and costs less than a $100). You can also choose to mail them (or hand them) to a professional scanning service that will scan them for you and mail you back the originals and a DVD with the digital scans (such services include www.digmypics.com, www.digitalpickle.com, www.britepix.com and many more)

There are pros and cons to both scanning at home and using a professional service. If you have a small number of photos scanning at home is easier. If you have plenty of photos using a service might be easier but you can end up spending more money.
When scanning at home consider the following:

Resolution: the resolution of a scan is measured by the number of dots per inch that the scanner can produce. Most scanners can scan at 1200 DPI or more. Usually the scanner can be set to scan at different resolutions. The higher the resolution the slower the scan and the bigger the photo file size will be. For most paper prints scanning at 300 to 600 DPI is enough but you can experiment scanning at higher resolutions if you feel it provides better results.

Speed: If you have a small number of photos speed is not an issue. If you have hundreds or more of photos scanning speed becomes important. To get fast scans you would have to scan at the lowest resolution possible that results in good enough scans – for most paper prints 300 to 600 DPI is enough.. Also if you’re going to buy a scanner check the scanning speed (usually measured in the number of scans per minute make sure that you check the speed at the DPI you’re going to use).

Photo feeding: if you only have a small number of photos this is not an issue. If you have many photos make sure that the scanner you buy allows fast and easy loading of photos. Some higher-end scanners will let you load a stack of photos and will automatically feed and scan them for you. These scanners are the right choice if you are planning on scanning hundreds or more photos.

Scanning negatives and slides

Scanning negatives and slides is harder than scanning paper prints. In most cases it is easier and maybe cheaper to use a professional scanning service (such services include www.slidescanning.com, www.myspecialphotos.com, www.pixmonix.com and many more). If you want to scan at home your standard flat scanner will not be good enough. In most cases you will need to spend money on purchasing a film/slides scanner. Those scanners are more expensive than the flat paper scanners. Negatives and slides are small high resolution sources and thus require scanning at higher DPI than paper prints. In most cases 2400DPI or higher should be used.

The considerations for scanning negatives and slides are similar to scanning paper prints. If you need to scan just a few negatives or slides speed and ease are not important but if you’re going to scan hundreds or more you should spend more money on scanners that can feed the negatives or slides automatically or can just load a roll of film and scan it.

You can find more information on digital photo printing printing and photography in general on printrates.com - a site dedicated to photo printing This article can be reprinted only if the resource box including the backlink is included.

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Ziv Haparnas

Methods for photo backups

2007-11-09T23:30:00.001-08:00

So you have finally decided to backup those precious photos? There are a few ways to backup photos. In this article we will explain how you can backup your photos either yourself at home or by using an online backup service.

Backing up to a DVD/CD

Backing up to a DVD/CD is done by using a DVD/CD writer and software that can burn files on such media. Usually using such solutions requires more technical know-how. Backing up to a DVD/CD is a cheap solution. You can buy such writer drives and software for under a $100 and each DVD/CD media should cost much less than a dollar. One such software that is used by many is from the company Roxio.
When backing up your photos to a DVD/CD please keep the DVD/CD in a safe place a good option would be somewhere out of your home maybe a family member’s home, with a neighbor you can trust or with a friend. Another thing to remember with DVD/CD backups is that when you take new photos you should remember to refresh your backups. Usually unless your photo album is very big the easiest way to do that is just to burn again you complete collection.

Backing up to an online backup service

As many other services backup also found its way to the Internet. A number of sites provide backup services today for everything from digital photo albums to your word documents. Those services usually charge a monthly fee in the $10 to $20 but some provide a more limited service for free. The idea behind the service is simple: instead of backing up to a DVD/CD you upload your photos to a site and create copies there. The site stores the backups in a safe place far away from your computer. If a disaster happens and you need your files you can simply download them back from the site or have the site send you a DVD/CD with the files (not all provide the latter option). A broadband connection is needed in order to use this option.

There are many advantages to using an online backup service. First they are usually very easy to use. Some provide software that you download and install on your computer. You point to the folder where your photos reside and the software takes it from there. It will make sure new files are uploaded to the backup service and that the backup is always fresh.

Examples of sites that provide such service are: Streamload that starts with a basic FREE 10GB space (approx 10,000 photos at 2 megapixels) and Xdrive that starts from 5GB for $10 a month.

Information about photography and photo prints is on printrates.com - your home for digital cameras This article can be published and used as long as the resource box including the backlink is included. Mr. Haparnas writes about practical technology issues.
Author Info:

Ziv Haparnas

What is PPI – Pixels Per Inch?

2007-11-09T23:29:00.001-08:00

The term PPI is not used much. Many people confuse PPI with DPI or have never heard the term PPI. PPI is a measurement of the quality of a print and understanding this term and what the number means can help you determine the right sizes and resolutions for your next digital photo print.

PPI: stands for Pixels per Inch. PPI describes the number of pixels per inch in a photo. PPI is a function of the number of pixels the camera’s sensor supports (also known as megapixels) and the size of the photo. To calculate a photo’s PPI simply multiply the page length by its width in inches. The result is the number of square inches on the page. Now divide the number of pixels the sensor supports by the number of square inches. The result is the number of pixels per square inch. All that is left to do is to find the square root of this number. Following is a table that shows the PPI for various page sizes for a 5 megapixel camera.

page size 4X6 - 456 PPI
page size 5X7 - 377 PPI
page size 8X10 - 250 PPI
page size 11X14 - 180 PPI
page size 16X20 - 125 PPI
page size 20X30 - 91 PPI

Information about photography and photo prints is on printrates.com - your home for digital photo printing This article can be reprinted only if the resource box including the backlink is included.
Author Info:

Ziv Haparnas

What is DPI – Dots Per Inch?

2007-11-09T23:20:00.000-08:00

You have probably heard this term many times before especially in the context of printing your digital photos. DPI is sometimes used as a measurement of digital photo printing quality while the truth is that DPI is an indicator of the printer quality.

DPI stands for Dots per Inch. DPI is a physical characteristic of a printer. Every printer prints dots that when put next to each other comprise a photo. Each dot has a physical size. DPI is also known as the maximum resolution that a printer is capable of. Low-end printers have lower DPI while high-end printers have higher DPI. DPI is defined as the number of dots a printer can print per inch. For example if a printer supports 1200 DPI it means that the printer can print 1200 dots per inch (on both X or Y axis). When printing it is important to make sure that the DPI is higher or equal to the number of pixels per inch in the source photo. If the DPI is lower the printer will not be able to fully display the high resolution photo. When the DPI is higher the printer will use multiple dots to represent one photo pixel. DPI is not relative to the page size. DPI is a fixed number for a given printer.

Information about photography and photo prints is on printrates.com - your home for digital photo printing Mr. Haparnas writes about practical technology issues. Ziv Haparnas is an expert technology writer. This article can be published as long as the resource box including the backlink is included.

Author Info:

Ziv Haparnas