1 Answer

Optical zoom is equivalent to you physically moving closer to the subject (although your lens does the moving not you) so you capture the actual image without any kind of digital manipulating on the part of your camera. The result is a clear shot, just like any other photo.

Digital zoom is where the camera crops and enlarges the part of the photo you are trying to zoom in on. So it's not really a zoom, its just an enlargement. When you enlarge a photo, your camera has to make up the spaces in between the pixels (those tiny color blocks that make up the photo) that didn't exist in the original shot.

The problem is that cameras aren't that smart, so the result is always blurry and sometimes discolored in areas because the camera's software duplicated the wrong pixels. This process is called dithering by the way, and there's more than one way to dither, but none of the dithering technologies is anywhere near being close to fooling the eye. That's why optical zoom is the only thing you should look at when considering a camera to buy.