Removing banding

Yehuda

• 2023年11月02日 23:55

Hey! I'm editing a RAW picture (ARW from a6400) in Capture One and when raising the exposure almost to +3 I get this banding, is it this impossible to fix because of bit depth? or is there some way to smooth it out?

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  BeO

  • 2023年11月03日 06:52

  

  Bit depth of your raw file?

  Probably more noise than signal, and maybe some quantization error when storing the noise in the raw file into the lower bits.

  See this article if you are interested:

  https://www.dpreview.com/articles/4653441881/bit-depth-is-about-dynamic-range-not-the-number-of-colors-you-get-to-capture

  I suggest to read the complete article (if you are interested), but I like to quote:

  Or to look at it from the opposite perspective: if your camera is overwhelmed by noise before you get to 12 stops of DR, you don’t benefit from more bit depth: all you’d be doing is capturing the shadow noise in your image in greater detail.

  "shadow noise in your image in greater detail" maybe would have been beneficial here, if the noise is assumed uniform in your image, because you want to increase the exposure so much, but I tend to think your aperture blades cast some signal (light) on the noise floor (so the opposite of a sunshade casting a shadow on a lit ground), and the Sony raw processing (prior storing the raw values) 'help' to create that visible step.

  That assumes your aperture was not wide open. And all the rest are non-scientific assumptions from me too.

  What can you do?
  I would try linear curve in base characteristics and use the curves tool which gives you more control. Try the HDR tool too, maybe brightness instead of too much exposure, play with color noise reduction.

  Another idea is a layer mask, maybe circular, and the skin tool editor to smooth the differences (using the uniformity sliders) of the noise/night sky mixture.

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