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

Started Apr 17, 2015 | Discussions thread
OP bclaff Forum Pro • Posts: 10,976
Re: Clarification - Read Noise and Engineering Dynamic Range

Detail Man wrote:

bclaff wrote:

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.

I guess so. Somehow, SNR of the sensor illumination remains the same regardless of levels ? ...

No, you get various SNR values that you can use to construct a PTC for example.

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.

It is the King of non-reducibles, with Sharpness and Brightness all forming a ... triangle ! ...

Triangle is a dirty word and an entirely separate topic.

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.

I certainly have (check my thread history). Such makes mysterious psychoacoustics seem simple.

What you see and what I see might be very different. (For example, what color was that dress anyway )

The punch-line was the chest-bumping insistence that "global reality" (of others minds) mus surely comport with one's own subjective perceptions - or "soundness of mind" may be called into doubt.

My favorite enduring (and silliest premised) questions surrounding musical experiences are: what is the best musical interval ?: what is the best chord ?; what is the best timbre ?; what is the best muical instrument ?; what is the best piece of music ?; who was/is the best musical artist ?", etc. Marrying machines together with aesthetic perceptions is often mysterious. Attempting to base rational debates upon the shoulders of "intangibles" is dicey.

The answers to all these questions is obvious ... to the observer


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