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

Started Apr 17, 2015 | Discussions thread
J A C S
J A C S Forum Pro • Posts: 14,716
Re: Clarification - Read Noise and Engineering Dynamic Range

bclaff wrote:

Horshack wrote:

bclaff wrote:

However, normalized read noise is not photographically relevant; and the DxOMark Landscape Use Case score is supposed to be a photographic use case.

Read noise is not relevant to whose photography specifically?

I think I could have been more explicit.
I mean that a measure that is solely read noise and has no photon noise component is not photographically relevant. (It has engineering relevance.)

Are you sure that photon noise is not taken into account by DXO (I do not know the answer). Their definition is a bit loose, and regardless of the definition, it would be interesting to know how they actually measure it.

Let is say they measure the read noise of a black frame and convert it into stops below saturation, like 20 e-. But at that level, the photon noise can be computed as a square root. Whether they add it or not, I do not know but in any case, you can add it to the read noise (in quadratures). So it is not difficult to include the shot noise as well; and that is a small correction unless the number is too close to 1 (normalized to 8mp) but we are far from it with most sensors, I believe.

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