In this day and time I would be careful about a declaration that there is "no way" that a technology (combination) under discussion is possible. The rumored "way" is a new-technology variable ISO technique previously mentioned on this and other forums:
http://www.apical-imaging.com/UserFiles/ad-iso.pdf
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It's not clear to me what this Apical system is doing. Having looked at their website, it seems that they've developed a system to analize and process the data in a particular way
after A/D conversion and
after the signal has been read.
Anyone who's taken the trouble to compare equal exposures at ISO 100 and ISO 1600, from their 5D or 20D, should be very impressed with the vastly superior shadows that the ISO 1600 image contain. The difference is like chalk and cheese.
Whether you compare a correctly exposed ISO 100 shot with the overexposed ISO 1600 shot, or a correctly exposed ISO 1600 shot with the necessarily underexposed ISO 100 shot, the difference in the shadows noise and general quality of the image in the shadows, including resolution, is huge.
I understand that Canon achieve this low noise result at high ISO by applying an anlog boost to the voltage from each pixel prior to A/D conversion. The ISO setting determines the amount of preamplification applied.
Apical appear to claim they are applying a variable ISO value to different parts of the scene, after software analysis of the scene. This seems to me like a variable fake ISO, in a similar manner to Canon's ISO 3200 which in most of their models is the same as ISO 1600 underexposed one stop with digital values later multiplied, together with all noise introduced by earlier processes in the chain.
The following crops of shadows are from equal exposures; same lens, same F stop, same shutter speed, but different ISOs. The ISO 100 shot was close to a correct ETTR, maybe 1/3rd stop underexposed. The ISO 1600 shot was of course overexposed.
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