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View Full Version : Digital Zoom, Optical Zoom



Dosci
07-11-2004, 02:06 AM
If you have a camera that has 3x digital zoom and 3x optical zoom which one does what?
I mean when does it digital zoom and when does it optical zoom?

Why does the camera even have digital zoom and optical zoom in one camera?

Jake Conner
07-11-2004, 10:17 AM
Optical zoom changes the focal length of the lens by moving lens elements, resulting in no loss of quality. Digital zoom is a marketing gimmick that simply enlarges the center of the frame (something you can do better in software), resulting in an exponential loss of quality (2x digital zoom = 1/4 quality, 3x = 1/9, and so on). Usually, a camera with both will zoom optically first, then zoom digitally if digital zoom is active (you usually can - and always should - disable it). Some cameras (Fuji S602, S7000, S20, as well as some Sonys) have a smart digital zoom that can only be used at lower resolutions and does not degrade image quality.

Jake

John_Reed
07-12-2004, 01:52 PM
Optical zoom changes the focal length of the lens by moving lens elements, resulting in no loss of quality. Digital zoom is a marketing gimmick that simply enlarges the center of the frame (something you can do better in software), resulting in an exponential loss of quality (2x digital zoom = 1/4 quality, 3x = 1/9, and so on). Usually, a camera with both will zoom optically first, then zoom digitally if digital zoom is active (you usually can - and always should - disable it). Some cameras (Fuji S602, S7000, S20, as well as some Sonys) have a smart digital zoom that can only be used at lower resolutions and does not degrade image quality.

Jake
Traditionally, I'd agree with you Jake, but I've been getting some pretty sharp results with my FZ10 in its digital zoom range. Here's a shot I took yesterday of a Cormorant fanning his wings, no post-processing, cropping, or sharpening employed, at full optical zoom + 2.4X digital zoom, handheld:
http://john-reed.smugmug.com/photos/6034589-M.jpg

Jake Conner
07-12-2004, 07:38 PM
Yeah, but you could probably have done better just cropping and upsampling in Genuine Fractals....

Jake