Zoom Capability

Film cameras had only one kind of zoom. You bought a special lens that gave you the ability to change the focal length, or distance between the lens and the film. This is called optical zoom and requires that the lens actually move. Optical zoom magnifies the subject and the quality of the magnification is as high as without zooming. In other words, when you use the optical zoom of a 5MP camera, the image you get would still contain 5 million pixels. Using the optical zoom is the same as just getting closer to your subject and taking the picture.

The lens brigs you close so you don't have to.

The advent of digital cameras has brought a confusing term into the picture, the so-called digital zoom. For all purposes, this is not really zoom at all. The lens does not move to perform this. All that occurs is the camera enlarges a portion of the image. In other words, instead of enlarging your subject, you are enlarging part of the image. This results in loss of quality. If a 5MP camera takes an image using digital zoom, the resulting image has less than 5MP.

Everything that a digital zoom can perform can be done with an image editing software. But if you don't want to use (or don't know how to use) an image editing software such as Photoshop, you may prefer to use the digital zoom.

Virtually all digital cameras have digital zoom to some extent. The amount of digital zoom should not influence your buying decision because you can still get the same effect with image editing software. However, optical zoom - the real zoom - is an important feature that gives you a lot of flexibility. The higher the optical zoom the better.

When comparing between cameras, always compare only the optical zoom. Some manufacturers use what I consider to be a tricky label, by combining the optical and digital zooms into one; something like 2x optical and 3x digital for a total of 6x. That is deceitful and the consumer should be wary. This practice is especially heinous in digital video cameras where the digital zoom is as high as 300x.

A 3x optical zoom is standard with most consumer digital cameras. A 2x optical zoom is disappointing, but not necessarily a show-stopper. Some ultra-compact digital cameras may be able to provide only 2x optical zoom. Since optical zoom means the lens has to actually move, cameras with high optical zoom cannot be as thin as those without. The camera has to be thick enough to allow the zoom lens to go back in its hiding place. I never bother to check how much digital zoom a camera provides, and ignore the marketing hype surrounding it. Personally, I always disable digital zoom in camera, choosing to do my own cropping and enlarging in an image editing software.

Optical vs. digital zoom? There is no contest. Only optical zoom matters when selecting a digital camera.