I've been told that some digital zooms distort resolution. What should I look for and be aware of re: zooms when purchasing a digital camera? And which mid-range and upper-range cameras offer the best zoom options? Thank you.

-- Grant Smith (grants@nidlink.com), September 25, 1998

Answers

All "digital zooms" are going to have a drastic effect on resolution, since they're basically either just cutting down on the number of pixels used from the CCD (resulting in a smaller image that shows a smaller area of the target), or doing that plus interpolating back up to the original image size (resulting in a larger image that shows a smaller area of the target, but contains no additional information.)

If you go to the "pictures" pages on this site for the Kodak DC260, DC220, the Casio QV-5000, Toshiba PDR-M1 or the Olympus 340, you can find sample images taken with the digital zoom enabled. (I think essentially all of these will be of the resolution test target, but they'll give you a pretty good idea of what to expect.) - Quickest way to get to the pictures pages for each of these is to click on the "Digital Cameras" navigation bar entry on the left, and then just click the appropriate link next to the camera name you're interested in.

As to "best," that's going to depend a lot on what you're trying to do. If you like the smaller picture/smaller area approach, look at the Toshiba, Oly, or Casio. If you want the image to be resampled up to a larger size, the Kodak 220 & 260 are nice in that they have a variable ratio digital zoom, so you don't get more interpolation than you absolutely need.

-- Dave Etchells (web@imaging-resource.com), September 30, 1998.