Exposure basics, lesson two point one (& ISO)

Started Mar 19, 2013 | Discussions thread
Anders W Forum Pro • Posts: 21,468
Re: It's about useful comparisons - not which is better

Jack Hogan wrote:

Anders W wrote: I will be back with a reply to your entire post. But before that, it would be helpful if you could specify exactly how you ended up with these particular SNR figures. I realize, of course, that they are based on measurements from the area below the letter A of the gray scale. But exactly which area did you select in the two images (RawDigger left/top corner positions and width-height values), what sample statistics did you observe for these areas, and how did you use these statistics to compute the SNRs that you present. The reason I am asking is that the values I come up when trying to replicate what I think you did do not match yours.

These are my measurements and initial calculations. But, aside from potential cock-ups in the readings, do you agree with my methodology?

I'll return to your choice of methods when I discuss your post in its entirety. But let's sort out the measurements first.

You didn't answer the question of exactly what area you selected in the two images. Could you please do so.

In case you didn't record that information, please give me a new selection that you consider appropriate and the statistics associated with that new selection.

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