Other problem is that at some point lens flare, blooming, reflections across the CCD etc. become limiting. You can have 16 bits of SNR from the camera electronics package, but that is measured using localized detector illumination generated by an ideal optic. In actual practice, the intrascene DR is limited by optical flare from brighter regions or electronic contamination from detector areas that contain bright data. In my experience, the electronic contamination is much more pronounced with CMOS and the like than with CCDs.
I've heard of this DR limitation due to lens flare mentioned before but I can no find no specifics or examples or comparisons.
We're all familiar with the obvious examples of lens flare when the camera is pointed in the direction of the sun or some very bright reflection. However, the proposition that lens flare, even when the sun is behind the camera and when a lens hood is in place, will still limit dynamic range, needs investigating.
The questions that spring to my mind are:
(1) What is the DR limit of lens flare, in terms of EV or F/stops, in lenses considered to have the best flare protection?
(2) How does such a limit vary amongst different models of lenses?
(3) Is there any benefit, in terms of shadow quality, to be gained when the DR of the sensor exceeds the DR limit of the lens used?
Before I bought the D7000, I attempted to find out just how significant in practice were the DXO claims of such exceptional DR for the D7000.
I came across a lot of negative comments along the lines of, "Roger Clarke has demonstrated that shot noise is the predominant noise in DSLRs at extemely low 'pixel saturation' and therefore claims of 13 stops of DR are meaningless in practice."
Yet, oddly enough, the standard studio scenes used by Dpreview in their reviews of cameras demonstrated clearly, cleaner shadows in the D7000 images compared with, for example, the Canon 60D, so this claim of 'shot noise' limitation on DR seemed bogus to me.
Shortly after taking delivery of my D7000, I retrieved from my archives a Dynamic Range Test Chart created by Jonathan Wienke for the purpose of assessing the subjective significance of DR limitations.
But such a method completely bypasses the problem of lens flare since it involves progressively reducing exposure of a fixed target under constant lighting conditions, then examining the quality of the image which has been underexposed by a specific number of EVs.
Below are two exposures of this test chart which differ by 13EV, the first one is a reasonable ETTR at 4 seconds' exposure, and the second exposure at 1/2000th of a second demonstrates the extreme degree of image degradation in the 14th stop.
Needless to say, image quality 3 stops up from the 14th stop, the 11th stop, is much, much better, and quite acceptable for shadows.
Can anyone comment on flaws in such methodology?