Ask the Teaboy

Q: What's this optical zoom, digital zoom business? What's the difference?

A: Good question - and important to know when buying a digital. Most digital cameras come with both an optical and a digital zoom. There's a big difference between the two. Generally people should be interested/concerned primarily with the optical zoom. An optical zoom physically zooms in on an image by use of movable glass elements that change the focal length of the lens. It is the same as the kind of zoom lenses we're all familiar with from regular film cameras.

The 'digital zoom' feature has arrived with digital cameras, and it is simply a crop of the scene you're looking at - the same as opening the image file later in your computer software, and selecting a central portion and deleting everything outside of that portion. Generally you can use an optical zoom without regard to the effect on the quality of your image, but with a digital zoom you need to keep in mind that as you 'crop' your image you are effectively discarding pixels as you zoom. The only real benefit to having a digital zoom is that it saves you having to crop your image later in your computer!

The more resolution the camera you have, the more digital zooming you can get away with. For example, if you own a 4 megapixel camera (which are capable of good 12x18" sized prints) you can use your digital zoom to crop in to less than one quarter of the scene you're composing, and still produce a good 6x4" or 5x7" print.

Another alternative to using your digital zoom is to buy a camera with a longer optical zoom (which enables you to zoom closer, without losing any resolution). As a general rule, however, the convenience of having a longer zoom can come at the cost of lens quality. Although modern technology is producing amazing quality results from very long zoom lenses, the fact still remains that shorter zooms still produce better images, and, at the farthest extreme, having no zoom at all can mean the best possible image quality.

Only you can decide what is highest priority for yourself - image quality, zooming convenience, or a cross between the two (a high resolution camera with a standard zoom lens, in combination with a digital zoom). If you need help deciding - let us know!