I get asked a lot of questions regarding cameras and photography. This week I’ll focus on one that may confuse some people: What’s the difference between optical zoom and digital zoom?

A camera manufacturer usually describes their zoom lens as “an optical zoom the equivalent of a 24-105mm.” This means it’s a wide-angle to medium telephoto zoom lens. At the 24mm end, the lens takes in a wide scene with a horizontal angle of 73.7 degrees. At the long end of the zoom, the angle of view narrows to 19.5 degrees. The ability of the lens to zoom in on a subject is achieved with the physical properties of the lens and the quality of its optical glass. It’s similar to how the optics of your binoculars or telescope bring distant objects closer.

On many consumer model cameras, you may have an option for a digital zoom. A digital zoom is engaged at the point of your optical zoom’s longest reach. In the example of the 24-105 lens, after you reach 105mm the optical zoom ends but a digital zoom can be engaged to effectively enlarge distant subjects. But your camera is no longer using the optics of your lens to accomplish this. Rather, your camera is only cropping in farther on your camera sensor to make it appear that you are enlarging your subject. Your camera is digitally creating the larger image.

This can work fine for some situations, but be aware that you risk losing quality the farther you reach with a digital zoom. If you have imaging software on a computer at home, you can do pretty much the same thing by just cropping in on any photo file. Voila — digital zoom.

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After writing my last column on repairing broken camera gear, a reader informed me of a long-time camera serviceman in Topeka. Phototronic, 119 NE U.S. Highway 24, offers free estimates and repair on all types of photographic gear from vintage cameras to the latest digital equipment.

This Alexander Gardner photograph of Mushroom Rock in the Smoky Hill region in the north-central part of the state is from Gardner's book Across

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On another note, I’m eager to get to the Nelson-Atkins Museum of Art in Kansas City, Mo., to see the exhibit “Across the Indian Country: Photographs by Alexander Gardner, 1867-68. The exhibit highlights Gardner’s work traveling along the Kansas Pacific Railroad route and documents many images in Kansas, including some near Lawrence. You can read about Gardner and see some of his work in this past column.

— Chief Photographer Mike Yoder can be reached at 832-7141. Check out more photos at ljworld.tumblr.com.