optical zoom
Definition:
Optical zoom refers to using your digital camera to zoom in on, or magnify, your subject. The amount you are allowed to zoom is usually indicated by a number followed by an x such as "3x optical zoom" which in this case means the ratio of the longest to shortest focal length on the digital camera lens is 3:1. Optical zooming uses the digital camera's lens to perform the zoom which produces a far superior picture than optical zoom's counterpart, digital zoom.