Though they often look like traditional film cameras, digital cameras take pictures electronically. The image is captured by charge-coupled devices (or CCDs, light-sensitive semiconductors) and generated as pixels, then stored as a file. After the picture is taken, it can be immediately seen--there is no photo-processing involved. Many digital cameras have LCDs (liquid-crystal display) in the back of the camera for image viewing. The image can also be seen on a computer monitor or television screen, again right off the camera if the camera has a video-out port. Digital camera technology has been a boon to photojournalists and other professional photographers, and continues to make headway in the consumer market of the late 1990s. Indeed, more than 2 million digital cameras were sold in 1997.

Introduced to consumers 1994, digital cameras have several advantages over film cameras. There are no film or processing costs, which eventually offsets the higher...