Optical vs Digital Zoom
If you are using a digital point and shoot camera you may have something called "digital zoom". In order to preserve maximum image quality you should avoid digital zoom whenever possible. If it is your only option, use it. If you have the option of optical zoom, use that instead.
- Digital zoom
Digital zoom is basically a digital crop within the camera. It is not a true magnification. When you use digital zoom you are effectively only capturing part of an image, with lower resolution than the full frame image would have. - Optical zoom
Optical zoom is magnification created by a lens. This type of magnification is a "true zoom" and should not adversely affect image quality. Optical zoom should be your first choice for magnification whenever possible.

