Can you explain how a SLR-like digital camera can have 12x optical zoon at the highest resolution but 18x at?

Question

a lower resolution? The camera in question is the Panasonic Fz8.

Answer 1

Cheating!



At lower resolution, it seems they are counting "lossless" digital zoom as part of the optical zoom, the lowest zoom being minimum optical and the whole of the the sensor used, scaled down to the target resulution, while the highest zoom is maximum optical and ony the specified resolution used on the sensor.



Actually, only half cheating, as unlike simple digital crop or digital magnify, you are getting the resolution you asked for, provided by cropping or scaling .

Answer 2

Once you get past the 12x optical, you are essentially zooming in on part of an image- similar to cropping a part of an image in a editing program and enlarging it- you do this at a loss of resolution in the editing program and in the camera. Digital zoom lowers quality and should be avoided if possible. Better results could be achieved by using the optical zoom and then enlarging in an image editing program. Here's an example that might make this clearer- if you had an image at 100 dpi and it was 4 x6- if you cropped it twice as large at 8 x12, you now have no more pixels than before and your resolution drops to 50 dpi- much too low to be of any use.

Answer 3

The above answers are correct. Let's assume that lower resolution was 1/2 that of the high resolution. What you could do instead is secretly take the photo at high resolution and then crop it to half size. Cropping is like zooming in. Because you were expecting 1/2 the resolution anyway, you got what you wanted.



All of this can be done with software. Always shoot at the highest resolution and make any adjustments with software later. That way you get to decide from the comfort of your own computer chair!



Regards, teef_au.

Answer 4

Optical zoom means taking the actual camera lens to the max. Digital zoom means taking the camera lens to the max, and then blowing up the image to zoom in further. Optical is the best quality while digital zoom will look very pixelated at high zoom levels.