Best location for Histogram peak

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zerolatitude
Posts: 156
Joined: Mon Mar 01, 2021 5:24 am

Best location for Histogram peak

#1

Post by zerolatitude »

Question regarding the usage of the smart histogram.

I'm using RAW16.

I presume the best location is for the left of the histogram to be just beyond the amber band in the top bar(so that Read noise is less than 10% of total), and the right to be well within the dark green band in the lower bar (so that it is benefiting from the 16 bits). The "Well within" is so that the faint signal to the right of the sky peak also comes within the dark green band.

The Exposure / Gain should be finetuned to achieve this even if this results in a very "thin" histogram in linear mode.

Is this understanding correct?

Thanks
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admin
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Re: Best location for Histogram peak

#2

Post by admin »

Hi,

putting the left hand side beyond the orange bar is correct - that ensures that even the darkest areas satisfy the minimal read noise rule.

For the other bar it's better to think of that in terms of 'do I need to use 16 bit' rather than as a guide to where you position your histogram. If all of your histogram peak is in the light green region then you can switch to 8 bit with no real loss of information. If part of the peak (or at least part that you care about in the final image) is in the dark green then you should go with 16 bit. There is no downside to part of the histogram being in the light green when in 16 bit.

Robin
zerolatitude
Posts: 156
Joined: Mon Mar 01, 2021 5:24 am

Re: Best location for Histogram peak

#3

Post by zerolatitude »

Its useful to know that there's no downside if part of the 16 bit histogram is in the light green section.

My attempts to get it all (including the right trailing edge) into the dark green zone results in a very thin histogram. That needs a lot of stretching which in turn seems to introduce quite a bit of noise.

I'll try this out.

Thanks
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