I'm trespassing from the Equipment part of CN as I think I'm finally able to articulate a quandary I've been having for some time.
ISO - what is it, at camera electronic level? Sounds like a banal question but I mean it at deeper level - so switch off your school bus:)
Two-line background: thinking about the rest of the triptych it's quite easy: aperture and exposure are physically modulating the amount of light landing on a sensor.
Also, in the old days it was - I think- the grain size or otherwise characteristic of the reacting medium on the film - again something physical I can grasp.
So what is ISO in a DSLR? Is it 'just' the electronic gain? Does it take place at sensor level or at the microprocessor level?
Does 'native ISO' makes any sense at all as a term?
Is the max ISO of a DSLR simply how much it's tolerated a grainy/noisy image thus being a loose measure of the noise quality of a camera?
Ok, forget the last question...