Why 'more or less stopped using ISO'?

Started Feb 19, 2014 | Questions thread
bobn2 Forum Pro • Posts: 52,297
Re: Why 'more or less stopped using ISO'?

edhannon wrote:

You will get two answers: absolutely yes and absolutely no!

Those the argue for keeping ISO at base and brightening in PP say that for ISO-less cameras you get no gain in SNR by raising ISO. They say that you can do better brightening in PP with the enhanced algprithms available in programs like Lightroom. Also you get greater headroom for highlights.

Those that argue for using the ISO setting in camera agre with the above but make the additional observation that pushing brightness in PP results in loss of bit precision and the risk of posterization.

They advocate setting exposure using ETTR to preserve highlights. I support this position.

I made the point about the distinction between developing to required brightness in 'P' and 'pushing in PP' above. 'Pushing in PP' is very non-optimal technique, and undoubtedly can result in posterisation if the processing has failed to pass sufficient information onto PP. However processing for the required brightness on a computer, as opposed to letting the camera do half the job can never result in either posterisation or loss of 'bit precision'. In the first case, the sole potential negative effect is increased read noise, which will result in less 'posterisation', and in the second case, the application of increased analog gain in the camera results in just the same loss of 'bit precision'.

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