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Below is a screen capture crop from Potoshop of an unaltered raw photo from my full frame Canon 6D taken with the new Canon 16-35 f4 L at 16mm, ISO 100, f22. I am seeing rings where I am expecting a smooth graduation of colour from the sun to the sky. It gets worse when I adjust just about anything in the photo, levels, exposure, saturation. Is this because there is just not enough data in this particular photo? I took 5 bracketed exposures and all the darker exposures exhibit this anomaly. What's going on?

EDIT: I should add, but not sure if it makes any difference, that it was unusually clear this day with extreme visibility and absolutely clear skies with no environmental haze. The clearest day I've experienced in years.

enter image description here

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The first thing you must realize is that what you are seeing on your monitor is not the raw file. What you are seeing is an 8-bit demosaiced preview conversion of the raw file created by Photoshop (or whatever other raw conversion application you are using) based on the current settings. You may even be seeing the embedded jpeg preview in the raw file that was produced by the camera at the time you took the photo if that is what you have selected in the Photoshop preferences section!

What happens when you move sliders is partially determined by the choices you have made in Photoshop's preferences section. You can opt for faster but lower quality previews or for slower but higher quality previews. When you move some of the sliders the application reconverts the raw data based on the changes you made and displays the new 8-bit preview. With other adjustments the application will simply increase/decrease the value sent to the display. In both cases the application also keeps track of what settings you have selected and saves them without altering the actual pixel data in the file. When you export/convert the file based on the current settings the application will do the actual conversion and produce a new file in the output format you have selected: TIFF, PNG, JPEG, etc. Especially if you have Photoshop set up to convert the preview of an image on your screen more for speed than quality, what you see on the preview will not look the same as what you see when you actually convert the file.

Try actually converting the file to a high quality JPEG (same resolution as the original file and full color depth for the jpeg standard with minimal compression and see if the resulting file shows the banding that you are seeing in the on screen preview. If not, then look at your Photoshop preferences and change those "fast rendering" choices to "high quality".

  • Thanks. I realized it was probably display related but your answer clarifies it. I am also using a laptop and it wasn't plugged in at the time which may or may not have compounded the issue. i tried full res export and it looks fine i think although my display isn't large enough to view in full res and full size but it does look like its fine. i will try to print a sample to see what it looks like. – Jakub Sisak GeoGraphics Apr 14 '15 at 12:58
  • Be aware your printing environment may or may not have some of the same issues... – Michael C Apr 15 '15 at 1:41
  • Yeah, if you were on a laptop running on battery, the biggest part of it was probably your video adapter's attempt to save power. – Michael C Apr 15 '15 at 1:42
  • @michael-clark: could you explain it more? – Euri Pinhollow Jul 23 '16 at 13:36

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