digital zoom
Definition:
Digital 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 "4x digital zoom". Digital zoom does not use any part of the camera lens to perform the zoom. Rather, it uses the digital camera's processor to crop a smaller portion of what the camera lens sees and then expands that part of the image to the original size of the picture. This can easily result in a grainy or blurry picture. For better zoom results, rely only your digital camera's optical zoom.
It should also be noted that many digital camera manufacturers list their zoom capability by multiplying the optical zoom by the digital zoom. For example, a camera with a 3x optical zoom and 4x digital zoom may be listed as 12x total zoom. Smart consumers will pay attention only to the optical zoom setting on their digital camera.