Shooting modes

Extended Optical Zoom

Written by Gail Bjork

An Extended Optical Zoom increases the zoom range of a digital camera with little, if any, loss in image quality. However a smaller image size than the largest size available must be used.

Digital camera lensAn Extended Optical Zoom enables the zoom ratio of a digital camera to extended beyond the maximum length of the optical zoom.  There is little if any loss of image quality like when using a digital zoom.

A digital zoom crops an image in camera. An Extended Optical Zoom trims the operational area of the actual camera sensor to increase the maximum magnification.

The Extended Optical Zoom has been compared to using an add-on converter lens. However, a converter lens reduces the size of the camera aperture size and results in a slower shutter speed. An Extended Optical Zoom does not.

Greater zoom range, smaller image size

Extended Optical Zooms work when a smaller image size is selected than the largest size available on a digital camera. For example, on a seven megapixel camera, a resolution of less than seven megapixels must be used. A  10X seven megapixel digital camera, such as the Panasonic TZ3, can extend the optical zoom up to 15X, depending on the selected resolution.


Click on above image to see a 100% crop of a photo taken at 18X zoom at eight megapixels, and a 28.7X zoom at three megapixels. When the images are reduced in size, you see little difference in image quality.

Before using an Extended Optical Zoom, determine if the gain in zoom power is worth the reduced image size.

Extended Optical Zoom is also known under other names such as Smart Zoom, Extra Optical Zoom and Safety Zoom.

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.