Sometimes known as "telephoto" or "true zoom," optical zoom works like the zoom on a traditional film camera. Elements within the lens move, reducing the field of view and making the object appear closer.
With digital zoom, the camera takes a small portion of an image and uses mathematics to artificially restore the file to its original size. Unfortunately, digital zoom also reduces the resolution of an image.
You can think of a Compact Flash or Smart Media card as a reusable roll of film for your digital camera.
A Compact Flash (CF) card is a small removable mass storage device, which weighs half an ounce and is slightly smaller than a matchbook.
Smart Media Cards, or Solid State Floppy Disk Cards, as they were known, are slightly longer but significantly thinner versions of Compact Flash cards. Like CF cards, Smart Media Cards use flash memory chips for storage.
A measurement, borrowed from traditional film cameras, of light sensitivity. The higher the ISO rating, the better the camera will perform in low-light conditions. Most digital cameras have ISO ratings of around 100.
The resolution of a digital camera refers to the sharpness of its pictures and is measured by how many pixels make up a photo, usually measured in the horizontal by vertical resolution. (i.e. 1280 x 960 Pixels = film resolution of 4" x 6" print).
The higher the resolution, the sharper the picture.
Fixed-focus cameras have a non moving lens that is preset to focus at a certain range. Higher-end digital cameras usually have auto focus instead, which automatically focuses the camera at your subject's distance.
Most cameras automatically determine the correct exposure for the lighting conditions, however there are cameras available that offer manual exposure compensation. This allows you to set the exposure a few stops brighter or darker.
Some cameras include additional features, such as red-eye reduction or night portrait mode. Red-eye reduction is ideal for photographing people or animals. It works by firing a series of short flashes before the final flash and exposure, making your subjects' pupils contract and preventing them from having glowing red eyes in the final photo.
Macro: this lens feature allows you to take close-up shots, usually within one foot or less and is useful for taking pictures of small objects.
Rapid-Fire Shots: If you plan on taking pictures of subjects in motion, you may want to buy a camera that offers "Rapid-Fire Shots.“
Remote Control: with this feature, you can take a picture without holding the camera.
Digital Camera – Buying Tips Approximate number of pictures a card will hold at highest resolution Camera Resolution 1 mega pixel 2 mega pixel 3 mega pixel 8 MB card 24 photos 12 photos 5 photos 16 MB card 48 photos 24 photos 10 photos 32 MB card 96 photos 48 photos 20 photos 64 MB card 192 photos 96 photos 40 photos 128 MB card 384 photos 192 photos 80 photos Note: If you reduce the quality of the images, you can double, or even triple, the amount of pictures that you can take for the same memory.