Digital versus Optical Zoom
Buying digital cameras
A zoom is a means of magnifying an image. A digital camera may have only one type of zoom, or it may have both digital and optical zooms. They both function in different ways and it is important to know how they work so that you can decide which type of digital camera is right for you.
Digital Zoom
A digital zoom works by cropping the image around the zoomed area and then discarding the unused parts of the picture. This means that the image left over is made up of fewer pixels. However, the camera can't simply enlarge the pixels within the frame to make up for the missing ones, as that would mean the photo would be far too blurry. Instead, the camera attempts to replace the missing pixels with what it guesses would have been the colour if the image hadn't been zoomed at all. Because this is always an estimate, the colours are rarely as sharp or accurate as an optical zoom. The camera uses very sophisticated technology to get the picture as correct as possible, but even the most advanced cameras can't replicate the simple precision of an optical zoom.
Optical Zoom
Optical zooms work using lenses and moveable components - the same way a zoom works on a traditional camera. By changing the distance between lenses, the "focal length" can be altered, reducing the field of view but increasing the magnification. Optical zooms do not change the number of pixels used to create an image, so result in clear zoomed photos.
Digital zoom vs. Optical zoom
So which is the best to look for when you're buying a new digital camera? The answer is that, while it is useful to have both forms of zoom, optical gives you much sharper images and better resolution than digital zoom. However, a digital zoom is very easy to use. For short distances or for beginners, it can be a very handy function. Another benefit is that you probably won't have to crop or alter the picture when it's in your PC.
The important thing is not to be convinced into buying a digital camera based on the power of its digital zoom. It's more significant to consider the power of the optical zoom - as well as a range of other features.