Zoom lenses
A zoom lens is one which moves in and out so that the camera can move from taking a broad landscape type picture to a 'head and shoulder' portrait (without you moving an inch).
There are two types of zoom to be found on digital cameras: optical zoom and digital zoom. Generally speaking, optical zoom offers quality by changing the focal length of the lens in the camera – the lens actually moves position. Most camera offer 3X optical zoom, though some offer 5 or more.
Digital zoom on the other hand is achieved by computer software processes within the camera. Basically, it takes a part of the image and enlarges it. This does not add to quality of the image, rather the opposite. However, it can be a useful feature on occasions when you need a little extra bit of telephoto.
