What is digital zoom?

[bnnrcn]

There are 'optical zoom' and 'digital zoom' in CIC's tutorial about interpolation.It says 'digital zoom' causes interpolation and shouldn't be used.I think I use optical zoom by turning my lense and adjusting the focal length.So,what is digital zoom and how it works?

[Shadowman]

It's a function on point and shoot and bridge cameras, usually identified by the user of the term "zoom multiplier". It doesn't apply to DSLR cameras. You'll know if your camera has it by the designation "T or W" somewhere on the camera body.

[Geoff F]

You can in fact create 'digital zoom' during editing simply by increasing the image size, then cropping back if required.

Additional pixels are created to 'fill in the gaps'. Well roughly like that.

And that method probably produces a better result than doing it in the camera because you can choose the interpolation method and do some careful sharpening.

Some camera manufacturers seem to think that having a massive amount of zoom will increase sales. So adding 'digital zoom' gives the impression of having a larger zoom range.

Something which is well worth ignoring if you want best quality.

If your camera has a digital zoom option you should be able to turn it on or off somewhere in the menu.

[bnnrcn]

Thank you John and Geoff.My camera is a DSLR (Canon 1100D) and I haven't seen any digital zoom option in the menu so far...So,I don't think I have to worry about it

[MrB]

As others have written, digital zoom is more likely to be found on compact cameras, and it can be useful, as those cameras don't have interchangeable lenses. When using it, recognise its quality limitations, and don't view or print the photos too large. For example, the Pentax MX-1 compact camera has a 4x optical zoom lens plus ~2x digital zoom. The following image made use of that combination:



to give the equivalent view of an approx. 220mm lens in 35mm format. It looks OK to me on my monitor.

Philip

[Manfred M]

Digital zoom is marketing "crap". Nicely said, resizing an image in post is simply resampling / interpolation of the data collected by your camera. It is not really zoom, as the image is constructed by enlarging the existing captured image and filling in the gaps.

[rpcrowe]

Binnur, that was an excellent question and you have received excellent replies. I think that is a win-win situation.