Digital Camera features

1. a jointed camera or LCD screen for getting 8" closer to the wall for wider field of view in tight quarters, for shooting over the heads of a crowd, around corners, for taking pictures of the ceiling by laying the camera on the floor (architectural photography), or for taking pictures with the camera held at the waist level.
   
2. internal optical zoom mechanism (allows you to take pictures in aquariums or from windows by placing the lens directly on the glass, to avoid reflections and glare from the glass)
3. removable batteries, so you can carry some spares
   
4. standard removable battery size, so you can buy throwaway batteries (available almost everywhere) if your rechargables can't get recharged in time. [if you have a couple extra rechargables, enough to last for a whole day of shooting, this isn't as critical as removable]
5. internal clock for timestamping pictures
6. ability to turn off the "digital zoom" feature, which is totally useless, because you can always perform that feature later with computer software.
   
7. ability to zoom while taking video (although video from digital still cameras is pretty tiny and almost useless, sometimes you really want to capture the motion, and because of the tiny picture, zoom is necessary for some such shots). Technology alert: most digital cameras take "QVGA" quality video, which is 320x240 pixels at 15 or 30 fps (frames per second). However, as things get smaller and faster, some digital cameras can now take VGA video, which is 640x480, at a full 60 fps. This is "real" video.
8. Technology alert: shutter lag. Most digital cameras suffer from shutter lag... the time between the shutter being triggered, and the time it actually takes the picture. With all of the early digital cameras, it is necessary to press the shutter release, and then continue holding the camera and the pose until the picture is actually taken. Some of the newer cameras now have reduced this lag to as little as a tenth of a second (quite acceptable, barely noticable). If you can't find specs for shutter lag, assume it is relatively slow and noticable (i.e. not a selling point for the camera, so left unmentioned except maybe buried somewhere in the manual).
9. Viewfinder. On non-SLR cameras (rangefinder), the viewfinder is done with separate optics, which only approximate the actual picture to be taken. Many newer digital cameras are eliminating the optical viewfinder, apparently to save costs. Some offer an electronic viewfinder, which is a smaller internal LCD,which does give you an exact (although small) image of the picture to be taken ... while these have some limitations, they at least allow you to compose the picture in bright sunlight, when the standard LCD on the back of the camera is hard to see. A viewfinder also allows you to hold the camera up to your eye, in a position less prone to camera jitter while taking the picture, which can be useful in low light without a tripod, and for people with shaky hands.
10. Technology alert: Zoom lenses. Long optical zooms are a great feature to have in a camera... the longer the better. But there are a couple issues. First, most of lenses do not go wider than 35-38mm (50mm equivalent). In cramped quarters, it would be nice to have a wider option on the bottom end. Secondly, a long lens magnifies not only the picture image, but also the camera jitter. Even if you have steady hands, shooting at more than 300mm is difficult. Image stabilization helps immensely, and should be a required feature for cameras with more than 6x zoom (but often isn't present). Of course the long end of even an unstabilized zoom is handy if you also use a tripod. Remember too, that long zooms require better lighting.
11. Technology alert: depth of field is inversely proportional to image sensor size. Digital cameras typically have a much smaller image sensor than 35mm film cameras. If you are used to choosing aperture settings to get a softened foreground and/or background focus, you will find that much more difficult on a digital camera than on a film camera. More details here

1. large, fast flash memory -- the bigger the better. It is easy to take 400-500 pictures a day at a place like the San Diego Wild Animal Park, or at a National Park, or an amusement park.
2. multiple media type USB 2.0 flash card reader (can read other people's camera cards that way). In general, a flash card reader helps save your camera batteries, versus hooking the camera directly to your computer. Even rechargables have a limit on how often they can be recharged. The readers all run off of USB power. Make sure your reader is USB 2.0 (also known as USB high speed), because USB 1.0 and 1.1 are much slower.
3. (multiple) rechargable batteries, and charger, and (for vehicle use) an inverter, so you can recharge while you travel.
4. Doubler lens to get that much closer to the subject
5. Slave sync external flash to compensate for the usually puny flash found on most digital cameras.