Is digital zoom a worthless gimmick?

Started Jul 25, 2013 | Discussions thread
jcmarfilph Veteran Member • Posts: 7,592
Re: Is digital zoom a worthless gimmick?

bssfujifan wrote:

I might well be wrong, but I cannot see the need to use digital zoom for taking a picture. It seems to me that post capture cropping would do the same job, but without the increased possibility of camera shake due to the effective increase in focal length obtained by using digital zoom. Could someone please tell me if the following reasoning is correct:

X2 digital zoom would double the effective focal length of the lens, but use 1/(2x2) = 1/4 of the sensor. Shutter speed would need to be twice as fast to cope with effectively doubling the focal length of the lens (or use double the ISO setting). Alternatively you could forget digital zoom and crop the picture post camera. Cropping to double the linear image size (equivalent to doubling focal length of the lens) would again result in 1/4 of the sensor being used. However, as this was done post capture there would be no need to use a faster shutter speed (or double the ISO). Also cropping would give more flexibility and fine tuning with composition than when using digital zoom at the point of image capture.

The only possible advantage I can see with digital zoom is that the image will look bigger in the viewfinder/screen, although there will be no additional resolution of detail as there would be when using optical zoom.

If I've misunderstood or overlooked something, I'm sure someone out there will be able to put me right. Thanks for taking the trouble to read this!

Pointless unless you are IDing very distant subject or you want to make sure the subject is in focus.

-=[ Joms ]=-

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