Grant (husband) wrote the following for another forum I belong to when someone asked how to choose a digital camera (especially for photographing fish). For those who don't know, Grant and I own a computer company and sell digital cameras (among other things) and Grant is interested in photography. Feel free to ask questions.
Here goes...
(Cees, feel free to put this in the articles section if you want.)
Some points to consider when looking for a digital camera.
1. How many pixels?
A minimum now is about 2Mp (2 million pixels). Cameras are available up to 4Mp or more. Some are advertised with a file size of 6Mp but probably has a 3Mp or 4Mp sensor. The extras are made up in the camera’s built-in software by ‘interpolation’. Interpolation is where the camera looks at adjacent pixels and calculates what would have been in the gap between these pixels and adds that to the final picture. It can improve the picture, but is artificial. The results are usually better than the 3Mp or 4Mp cameras normally provide, but not as good as a 6Mp one would produce. More pixels usually means more cost!
2. Sensitivity.
This is not mentioned in many ads, but is very important for low light photography. Often listed as the ASA rating. Look for a camera with a high rating as it will handle low light conditions better. Essential for photographing fish. A camera might have a standard setting of 200ASA but allow settings up to 800 or even 1600 on some newer ones. Often there is a trade off though. As the ASA (speed) is increased, the picture might become noisy. In other words, appear to have a grainy finish.
3. Response speed.
Another thing not often mentioned. Digital cameras all take some time from when you switch them on until they are ready to take a photograph. Some take up to 7 seconds or so while others are ready in less than 1 second. Doesn’t seem much, but most annoying when the subject is moving away! Along with this is the lag when you actually take the photo. Look for a camera with very short time lag after you actually push the shutter release. It is not unusual for a camera to release the shutter up to 1 second after you press the release. This makes it almost impossible to photograph a moving object. A good camera will have a lag time of less than 100mS (0.1 seconds) or better. Even this is a noticeable time. The other time to look for is the time for the camera to store the photo just taken and be ready for the next shot.
4.Lens.
Probably the most important part of the camera. A 2Mp camera with a good quality lens will take better pictures than a 3Mp (or even 4Mp) camera with a poor (ie cheap) lens. This is how some manufacturers are able to offer very cheap 3Mp cameras for a very low price. Don’t buy one. Along with the good lens, you want at least 3x optical zoom. Ignore the digital zoom. You can do this later on your computer if you want. If you use a 2x digital zoom, you have reduced the pixels in your photo by half (i.e. a 2Mp camera using 2x digital is the same as using a 1Mp camera with a 2x optical zoom). The ability to focus at close range (macro) is also very useful.
5. Batteries.
Most cameras have an LCD display for view finding, playback, and setting up the camera. These displays use a lot of power, so rechargeable batteries are a must. Lithium Ion (lion) batteries are used in many cameras. These are high capacity, so you will have longer time before the battery goes flat. It has complicated charging requirements, so you must charge the lion battery either in the camera or a purpose built (usually supplied) charger. Having a second battery is a good idea for when the one in the camera goes flat, but they are expensive. They don’t have to be completely discharged before recharging so that makes battery management a lot easier. Many cameras use AA size Nickel Metal Hydride (NiMh) rechargeable batteries. These are readily available from many suppliers and are reasonably cheap. An after market charger is also quite cheap. A charger that charges rapidly and automatically switches to trickle charge mode is a worthwhile investment and not very expensive. Because of this you can have a good supply of charged batteries available for when the camera ones go flat.
6. Viewfinder.
Only the very cheapest cameras don’t have an LCD display and viewfinder. However, make sure you choose a camera with an optical viewfinder as well as the LCD one. The LCD ones are almost impossible to use in bright sunlight, but do give the most accurate indication of what you are photographing. Check that the optical viewfinder tracks the (optical) zoom if you have one. There should be markings in the optical viewfinder to help correct for parallax errors.
7. Memory (i.e. storage).
There are many different types of memory used these days. There is compact flash, smart disk, , SD, memory stick, CD-R and even floppy disk. All of these types are readily available, but could disappear in the future. There is a small risk that this will happen for the type your camera uses, but you probably need a crystal ball to predict what will happen! I’m sure any of these memory types will be available for the life of your camera. Most would buy extra memory at time of purchase or soon after, so probably not too much of a problem. Go for the largest memory you can get (or afford!). Try to take all your photos at the highest quality setting. This will use much more memory, but you can always reduce the size and quality of your photos later if you want to e-mail them for example. You can not get back the quality lost by choosing high compression and small picture size. You might as well save some money and buy a cheaper camera with lower pixels and get the same results. My camera takes 36 photos on a 64Mb card at its high quality setting. It takes over 900 on the low setting. If you have a laptop computer, take it along so you can download your photos and so clear your memory as you go. Cameras using floppy drives for storage are disappearing from the market now. Due to the limited file size on a floppy disk, these are generally available on low pixel count cameras using high compression to fit more than one image per floppy. The time taken to write to the disk is quite long as well. Those using CDR storage are ok but very expensive and prone to problems with the delicate mechanical CDR drive.
8. Transferring to the computer.
Most cameras use the USB connection to transfer the images from the camera to the computer. Your computer must have USB ports and use at least Windows 98. Windows 95, even with USB support, usually won’t work. Apple computers with USB should be OK as well. Software to allow transferring the images from the computer is normally supplied with the camera, along with some editing software. Windows ME and XP don’t need drivers for most USB cameras. Just plug the camera in and it will appear as an extra removable drive. You will need a special USB cable though, supplied with the camera. Be gentle with it! If you break the cable or the camera connector, they are expensive to replace. Another option is to buy a USB card reader. This plugs in to a USB port and you insert the memory card in it. It then works as a removable drive, just as the camera would. Some of these readers will handle a number of different memory types. The advantage is you don’t have to keep plugging that fragile cable in to your camera. Saves reaching around the back of the computer if you don’t have front USB ports or a USB hub that is easy to get to. Also, if you have a number of devices (more than one camera, MP3 player, portable memory etc) you don’t need to keep all the different cables handy. If you have a computer without USB then the options are very limited. As long as you have at least Windows 98 then adding a USB card is a viable option. If you don’t have Windows 98 or later, then perhaps a new computer first might be a good idea.
9. Camera construction.
A few points to look for as this is a very subjective thing. I prefer a metal case if possible. They can withstand the occaisional bump and knock better than the more common plastic bodied cameras. Ensure you are able to operate the controls easily, and that you can access the memory card and batteries. Check that the camera is easy to hold and you don’t tend to have a finger across the lens or other sensors. A different design might suit you better. For photography in low light, ensure there is a tripod screw and that you can manually focus and set up the camera for aperture and speed etc. Most cameras have a built in flash, but they are usually quite low powered. The ability to connect an external flash could be useful, but not many cameras have this facility.
