Originally posted by jsherman999 1.There is no causal coupling of 'pixel size' to DR.

2. DR is a function of total light captured and sensor QE.

1. Correct

2. False, DR is no function of QE

Originally posted by Ikarus Those two statements are mutually contradictory. Since DR is a function of the total light captured, the number of photons collected by a sensor element increases with the size of said element, thus increasing its dynamic range (all else considered equal).

Wrong, DR is defined for the camera, not the pixel as DR is a function of spatial frequency.

Statements like the ones I cited are an example why I so strongly advocate the equivalence theorem. And it is a theorem really, not a simple conversion rule. Because it holds true in a strict physical sense (and its proof is non trivial) and it allows to understand things like the above WITHOUT the need to dig into physical considerations. Not every photographer is also a physicist ...

In a nutshell:

Eg. a mFT sensor with crop 2 and base ISO 100 has a 35mm-equivalent base ISO of 400 (100 *2^2). And at ISO 400, DR is 2EV less than at ISO 100. It is this simple, really. Just don't try to dig deeper, no need for it. And #pixels or pixel size plays no role at it, don't always pixel peep, not even when thinking about photography.

BTW, note that an ideal camera has DR(ISO,f) which is a known function (the equivalence theorem is 100% strict for ideal cameras only). Here, ISO denotes 35mm-equivalent ISO, f spatial frequency (LW/PH), and an ideal camera has noise=shot noise, QE=1 and base ISO of 0. A real camera's DR will remain below this known function. A lower QE of a real camera would shift the function to lower ISO, including the same shift for its base ISO, yielding in an unaltered DR at base ISO. The DR function is shifted left by QE<1, not up or down. A real camera's non-equivalent base ISO and QE are determined by the CMOS process rules, color discrimination technology and microlens design. Because the latter are technology-driven more than camera-model dependent, equivalence nicely applies to real cameras too. And of course, because real cameras are approaching the ideal camera more and more.

At this point, let me add one more note ... The ideal camera would score infinite DxOmarks because of its zero base ISO. Maybe, it is time for DxO to renormalize their scale such that an ideal camera scores finite.