Increasing zoom by reducing resolution

Started 1 week ago | Discussions thread
bobn2 Forum Pro • Posts: 61,740
Re: Increasing zoom by reducing resolution

John Sheehy wrote:

skyglider quoted Panasonic:

Extra optical zoom uses a reduced area of the image sensor (in the lower megapixel modes) to in effect crop the subject before the image is saved to the SD Card. There is no loss of quality when using extra optical zoom.

That is disingenuous on Panasonic's part. There is nothing "optical" about cropping. The only difference between this and historic "digital zoom" is that no resampling occurs, which has nothing whatsoever to do with "optics".

Up until when you actually display the image, when resampling of some kind inevitably occurs.

Each approach has its benefits. If you shoot RAW for maximum flexibility, an exact crop with no resampling is the best way to crop, always, but if one is shooting JPEGs, and JPEG processing and compression limits the expression of luminance and especially color resolution at the output pixel level, then more resolution survives the processing if the image is first resampled, despite some distortion created by the resampling. A 200% resampling does not cause any permanent distortion.

Thanks, John. That had been said by several, but got pruned. Making it clear is important, because otherwise people could get duped into believing what Panasonic said which is, as you said, disingenuous.

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263, look deader.

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