What\\\'s the difference between digital and optical zoom?

If you enjoy using your digital camera regularly and want to take the best possible photos, the difference between digital zoom and optical zoom is important. When you look through the sales literature that comes with a digital camera, however, this difference may not be clear.

Optical Zoom
Perhaps the best way of describing optical zoom is to put the idea of a digital camera out of your mind. Instead, think of a pre-digital 35 mm camera with a zoom lens.

The optical structure of this lens enables you to bring the subject of your photo much closer. So although the subject may be some distance away, you can zoom in and take a clear and detailed picture.

A digital camera with an optical zoom uses identical technology. In other words, a digital camera with a 12x optical zoom is the same in principle to a pre-digital camera with a similar zoom capacity.

Digital Zoom
A digital zoom is in effect a simulated zoom. It enlarges part of the picture on the digital camera’s screen. It does not use the optics of the camera to zoom in.

Think of it another way. Imagine you transfer a digital picture to your computer. You find you’re not happy with the photo because the subject is too distant and surrounded by unwanted background. So you use your photo-editing software to crop the photo and enlarge the subject. This is exactly what the digital zoom on your camera does.

Drawback
In theory, if you have photo-editing software, you don’t need digital zoom. But you’ll find that many cameras come with digital zoom anyway.

So should you use it in preference to optical zoom? The temptation is certainly there, particularly when camera makers give you digital zoom that appears to exceed the capability of optical zoom. One camera may have 12x optical zoom, for example, and another 50x digital zoom.

Faced with this choice, choose the optical zoom. And there’s a good reason why.

Use an optical zoom and you can take clear, sharply detailed photos. Use a digital zoom and you can lose significant image quality. After all, with digital zoom you’re simply enlarging a picture rather than truly zooming in. And the more you enlarge, the poorer the results.

This is especially true with digital cameras that have relatively low megapixel resolution. But even the images of high megapixel cameras can lose detail and become fuzzy when you enlarge them.

Digital Zoom Solutions
To be fair, digital camera makers have come up with some clever solutions to the problems of digital zoom and image quality. Check through any selection of good quality cameras with digital zooms and you’ll see references to technology such as Intelligent Zoom and Smart Zoom.

There’s absolutely nothing wrong with these. The technology plays with the megapixels of the camera in such a way that digital zoom has some of the quality of optical zoom. But in the process, you may have to compromise with a smaller print than the size you originally wanted. If you don’t, you can still lose image quality.

Jake Reacher owns a digital camera, with optical zoom. When looking at digital cameras he thinks the choice between digital and optical zoom is one you should think about carefully.