Photographic Dynamic Range (PDR) is a More Useful Measure than the DxOMark Landscape Score

Started Apr 17, 2015 | Discussions thread
OP bclaff Veteran Member • Posts: 8,712
Re: Clarification - Read Noise and Engineering Dynamic Range

Detail Man wrote:

bclaff wrote:

All I can say is that for PDR the illumination need not be calibrated in any way; since I'm gathering SNR values, it is "self correcting".

Fascinating. "Gathering SNR values" ? Could you elucidate a bit on that (in brief might be fine) ?

Imagine moving a kernel over the image and calculating the signal and noise within that kernel.
This produces a localized estimate for the SNR and you can take it from there.

Overall Image Quality (IQ) is obviously not dependent solely on dynamic range.

Have yet to see a mathematical identity for "IQ" - but "fractions of the elephant" can be inspected.

Yup, IQ is a concept, art not science, with no definitive measure.

I suspect differences in IQ between lenses has more to do with several other factors than some (possibly immeasurable) difference in dynamic range (which we are carefully trying not to confuse with contrast).

Small differences in (random) noise might well not be very noticeable - but qualitative and well as quantitative differences in periodic noise components seem like they (might) "be another story" ?

If we aren't headed deep enough into the weeds consider that probably no two persons visual systems are identical. What you see and what I see might be very different. (For example, what color was that dress anyway )


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