auto adjust puzzle

Timothy Devick

• 2017年11月20日 17:17

I opened a raw photo and did "auto adjust" (with all options except white balance checked). C1 adjusted levels but I went on to make a few more changes - bring up the shadows more and adjust some severe keystoning, then crop. I accidently hit the "auto adjust" button again and it auto-adjusted again and changed the levels. I didn't expect it to do anything the second time I hit it. Coming from LR, their auto-adjust works off the base image - before any cropping or adjustments, so any time you do auto-adjust on an image you get the same results. This doesn't seem to be the case with C1. Can you explain what's going on here please? Is it re-evaluating the auto-adjustments based on the cropped area of my photo, or maybe based on the adjustments I've made manually, or what exactly?

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  Ian Wilson

  Moderator

  • 2017年11月20日 19:22

  

  It may well depend on the crop. If you apply auto levels to an image that has, say, a bright area in one corner, the levels adjustment will take account of that and perhaps not move the right hand slider in much if at all. But if you crop the image so as to exclude the bright corner, and apply auto levels, it will move the right hand slider in by a different amount because the brightest point in the cropped image is not as bright as before. Also experiment shows that hitting the A button evaluates the image as it is cropped at the time. So for example I used the A button on an uncropped image and it applied a fair amount of highlight recovery and a slight reduction in exposure. I then cropped the image to exclude the brightest part, and hit A again. This time it reset the highlight recovery to zero, increased the exposure instead of decreasing it, and applied some auto levels which it had not done before.
  
  So that seems to be how it works, but whether it is different from how LR would work, I don't know. Personally I don't use the A button, though I do use the auto adjustment on some individual tools, such as levels.
  
  Ian

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  Benjamin Liddle

  • 2017年11月20日 21:48

  Additionally, it depends on what you have set in Preferences > Exposure. The Auto Adjust in the import dialog will adjust the RGB composite channel regardless of this preference, while the tool's A button will respect what is chosen (either RGB composite or Red, Green and Blue Channels).

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