Camera Parts

Types of zoom lenses

Written by Gail Bjork

Learn the differences between digital camera zoom lenses, which to use and which to avoid.

Compact camera zoomThere are three types of digital camera zooms, though the Optical Zoom is the only one that actually extends and retracts the lens mechanism.

Digital and Extended Optical zooms have their place, but not without some compromises.

Optical zoom

An optical zoom is a true zoom. As the focal length extends, an image is magnified by the lens itself.

An optical zoom produces the best quality images at all resolutions available on a digital camera. Zoom lenses can magnify an image 3X, 20X, 20X and more. Very long zooms are particularly prone to camera shake. To help prevent this, a gowning number of digital cameras that zoom incorporate Image Stabilization.

Extended optical zoom

An extended optical zoom trims the operational area of the actual camera sensor to increase the maximum magnification. Unlike a digital zoom, an extended optical zoom produces images with little loss of quality.

However, extended optical zooms may only work when a smaller image size is selected than the largest size (resolution) available on a digital camera. Not all digital cameras have extended optical zooms.

Digital zoom

A digital zoom is not a true zoom. It is a simulated zoom that enlarges the central portion of an image. The actual length of the lens does not change.

A digital zoom pre-crops the center area of an image. Resolution is reduced, giving the appearance of zooming in. It is similar cropping with photo editing software.

Because of reduced image quality, use a digital zoom only if you have no other options. Most cameras have a setting to turn off the digital zoom. This prevents inadvertent zooming into digital mode.

About the author

Gail Bjork

Gail Bjork, who is passionate about digital photography, is the owner and editor of Digicamhelp.Gail is the author of three illustrated ebooks about digital photography. A number of her photos and digital photography related articles appear at other websites.In 2006, a series of her photos, People in the Louvre, were exhibited at the Underground Photo Gallery
in Iisalmi Finland. Eight of her photos taken in the Florida scrub are on permanent exhibition at Parrish Medical Center in Titusville, Florida.Gail served twelve years as an elected member of The School Board of Palm Beach County, Florida, one of the largest school districts in the U.S. She has also been the editor of a small town newspaper and a free-lance writer. Gail and her husband owned and ran several small businesses.

4 Comments

  • hey great article.  it is easy to be confused by all the different types of zoom, but you have made it nice and easy to understand.

  • The resolution is reduced only if you use the Extended Optical Zoom setting (a feature not found on all digital cameras) or the digital zoom. Resolution is not reduced when using an optical zoom. As long as you used the optical zoom, a 14 MP camera should be just fine for making enlargements for wall art.

  • Why is resolution (or pixels per square inch) reduced when you zoom in.  I don’t understand that and am contemplating buying a 14 megapixel camera so I can blow up pictures to frame as wall art.  Any advice would be greatly appreciated.