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ISO on the R5

Started 10 months ago | Discussions thread
John Sheehy Forum Pro • Posts: 26,688
Re: I see!

Quarkcharmed wrote:

With all due respect to Bill's analysis, there must be gaps in the raw histogram which I don't see, so potentially it's more complicated than just digital multiplication.

Say if you multiply ISO 400 values to get ISO 500, you have to multiply each value by 2^(1/3) = 1.256, basically 5/4.

With integer digital numbers there will be gaps each 5th value - it won't be contributing to the raw histogram and we'll see the regular gaps.

A camera could do "corrections" differently for different lines of pixels, and fill a histogram that way, too; not just by using analog gain only. That's why you need to look at highlight headroom, too, to determine what is being done.

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Beware of correct answers to wrong questions.
John
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