Originally posted by falconeye Sounds cool. But isn't.
Because ISO doesn't do much else than amplifiying the available signal, you can achieve an almost identical effect in RAW postprocessing w/o lack of quality or DR compared to your proposal. I know, it was a joke. But anyway ...
That's not true. Setting the ISO on the sensor amplifies the
analog signal before the ADC stage. If you do the same thing in RAW PP you are amplifying the
digital information including all the quantization errors. At the analog stage you have an infinite amount of bits, in a RAW file you have 12, or 15, or whatever. If you take a picture at ISO 200 and amplify it to 1600 in PP you are using only a couple of bits per channel. It will look like junk compared to native 1600.
This is why ISO 3200 is so much worse than 1600 on the 6 MP Pentax bodies -- it is just 1600 digitally pushed a stop in firmware.