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

Started Apr 17, 2015 | Discussions thread
Detail Man
Detail Man Forum Pro • Posts: 17,073
Re: Photographic Dynamic Range (PDR) is a More Useful Measure than the DxOMark Landscape Score

Horshack wrote:

Detail Man wrote:

Horshack wrote:

Detail Man wrote:

bclaff wrote:

... The PDR criteria operates in the PTC region well above SNR=1 (at least until we get 384Mp sensors!).

In this region the subtle interplay of read noise, other noise, small amounts of photon noise, slope due to Full Well Capacity (FWC), etc. is captured.

It seems that (especially thses days, with higher performance image-sensors), Readout/Dark noise component are effectively "numerically swamped" by Photon Shot Noise. Rather "subtle", indeed.

But there's a distinct qualitative difference of read noise vs shot noise.

Seems to be a reasonable statement to make [surrounding specific visual observation(s) made].

It seems sort of like tentative, aesthetic territory. In the case of (completely) random noise components with a flat spatial frequency spectrum, the difference might seem to be (only) that sensor illumination is (also) increasing (by the square of the Photon Shot Noise increase). In the case of periodic noise components, individual perceived "qualitative" elements seem potentially unique.

John Sheehy once posted a simulation of an ISO 1,000,000 image with zero read noise and it looked more natural than a much lower ISO image with read noise.

Tried to find such a graphic (without success). Can you recall any particular "keywords" used in that post that I could "plug into" a (anything but the on-site DPReview, that is) "search engine" ?

Or, might you have a reference-link to John Sheehy's publishing of that graphic to provide ?

I just attempted myself and couldn't find it. Found lots of messages from John about the simulation but not the simulated image itself - I'm nearly positive he posted the image though. I remember reviewing it.

Perhaps John may be able to let us know about that at some point.

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