Originally posted by Ikarus I would still like to see you respond to the article I was

referring to Originally posted by Ikarus The laws of physics pertaining to scale usually aren't subject to revision.

Originally posted by Ian Stuart Forsyth I’ll look for papers Maybe Falk knows of this paper and can point me in the right direction

Originally posted by Ikarus I still don't see a smoking gun here and I really don't see how it could be any different, given that larger pixels just can't help it - they are bound to gather more photons.

This entire confusion is probably due to my inability to explain properly.

First, if you read my post

#215 again, I explained that even the ideal camera has a finite dynamic range which is a function DR(ISO,f) of both (equivalent) base ISO and spatial frequency f. DR(ISO,f) is both strictly monotonically decreasing with arguments ISO and f. And because it is physics (optics), there is no CMOS or sensor tech involved. No need to even read those papers.

Therefore and of course, a larger pixel (which corresponds to a smaller spatial frequency) has a larger DR. I need not to read the paper because it says the same. If you look at the dynamic range of a pixel, you look at DR(ISO,f=sensorheight/pixelpitch). However, we photographers only care about DR of the image (i.e., at some predetermined f), not DR of a single pixel.

If anybody wonders how sensor tech could influence these findings: not much, provided read noise isn't much larger than shot noise and quantum efficiency isn't much smaller than 1. Both being true now for the best sensors out there.

**Therefore, any understanding of dynmic range starts with understanding its property for the ideal camera (*).**
This is what I advocated and it is where equivalence (the attempt to really understand it) does actually help.

Therefore, I won't point to further literature of SNR properties of actual pixels on sensors. It would be misleading. Understanding is always more important than finding a reference for a claim.

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(*) An ideal camera is a camera registering angle and energy of each photon passing its aperture and shutter, with the finite precision allowed by the quantum nature of photons including

Heisenberg's uncertainty principle for the complementary variables of angle/aperture-size and energy/shutter-duration. Aperture and shutter may be virtual, i.e., they are just boundary constraints for photon wavefunctions in space and time, resp. The angle/aperture-size uncertainty is known as lens diffraction to photographers. The energy/shutter-duration uncertainty means that at ultra-short exposure times, color becomes uncertain. This is a non-issue for photographers (so far). The quantum nature of photons means images must be noisy with a finite exposure time.

An ideal camera does never clip, it has a native base ISO of 0. In order to define an ideal camera with a finite base ISO, I define an ideal camera with equivalent base ISO 100 to clip after 1.5E12 (1.5 trillion) registered photons. That's roughly the ISO standard as applied by DxO (for a 24x36mm sensor).

Therefore, DR(ISO=100,f=1/0.5) = 0.75 trillion:1 = 237 dB = 39.5 EV. And DR(ISO=100,f=2309) = 17.5 EV. For the ideal camera, using DxO's 8MP value for f when assuming a 3:2 aspect ratio. An ideal camera has no limit for f except for its diffraction limits. f=1/0.5=2 corresponds to an image half white and half black.

ERRATUM (added July 30):

The ISO 100 clipping level of 1.5 trillion registered photons applies to the current level of quantum efficiency (which is about 50%) and color discrimination filter absorption (which is about another 50%). Therefore, a truely ideal camera would have 2 more stops DR at ISO 100 which is close to 20 EV at ISO 100. Nevertheless, the disclaimer changes nothing about the remainder of the argument. As noted, QE doesn't affect the maximum possible DR.

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Last edited by falconeye; 07-30-2015 at 04:18 AM.
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