Could someone please explain to me what optical and digital zoom is? What is each one and how should I use this information to influence which camera I buy? Obviously, I don't know too much about photography, so please explain the practicality of each in a real world setting. For example, is a 2X digital zoom going to give the same results as a 2X Optical Zoom? Also, what's the deal with cameras that have both optical and digital zoom? Thanks a lot!

-- Kurt Vitense (kvitense@core.com), November 29, 1999

Answers

Optical zoom: mechanical zoom lens Digital zoom: software zoom

I did a search of this forum and found an answer for you. Probably a good idea to do a search before you post. Anyway, here is the most relevant answer:

The digicam marketing guys decided that if you have a 35mm wide angle setting, and a 105mm telephoto, that's 3x (these are 35mm photgraphy equivalents). At least they all do the same thing so it's not so confusing. I think in normal photography this would be a 2x lens. (105 is about a normal 50 times 2).

Digital zoom essentially just crops the image, so image resolution goes down the tubes quickly as you use more digital zoom. Bad. Optical zoom brings the whole CCD to bear at all settings. Very good. Optical zooms cost more, but if you want quality shots at telephoto settings its worth it. Digital zoom is handy in a pinch.

Most of the cams have 3x optical zoom, or just digital zoom. Some of the newer smaller cams like canon s10 and nikon 800 have 2x. The Sony 505 has 5x, and a good lens. The mavicas have really long zoom, but comparing image quality with other cameras, they're the absolute worst, unless you just want to post fuzzy pics to ebay. For ebay, having bad image quality is a plus, to hide defects in your product. :)

-- benoit (foo@bar.com), October 07, 1999.

Hope this helps

-- David Erskine (davide@netquest.com), November 30, 1999.

An optical zoom actually zooms using lens elements to change the magnification of the picture being taken. It's like looking at something and then looking at it through binoculars, etc. or looking at something and then moving closer or further away. It really resizes the picture like moving the camera (purists will note that the angle of view/perspective changes a little as well).

A digital zoom electronically crops the picture then expands what's left to fit the larger space. It's like an electronic piece of silly putty. Roll it on the newspaper and then stretch it out twice as big. All those pixels (picture elements) are now spaced further apart but there aren't any more of them. It can provide a certain amount of use if you are going to show the pictures only on computer screens. It's not real satisfactory for high quality (print) applications. Manufacturers like to combine the optical and electronic features to sound like a higher magnification is possible. I would not consider digital zoom as a feature in comparisons. You can do the same thing with almost all photo manipulation software by resizing the picture. Or simulate it by bringing up a picture of some sort and changing your screen resolutions. 640 x 480 gives a larger seeming picture than 800 x 600 but you can (usually) see the image quality get chunky. That's a "digital zoom."

-- Craig Gillette (cgillette@thegrid.net), November 30, 1999.