exposure adjustments with C1

Peter Walker

• 2009年06月23日 21:46

Shooting tethered to a P45, we are having an issue with exposure. Preface this by saying we check and re-check every setting, usually shoot at ISO 100. Images on our iMac look visually correct in exposure and tonality, yet the histogram is off (under-exposed) by at least two stops. When we correct using levels, the image appears overexposed by at least two stops- blown out.
Processing out to Photoshop and our images require further exposure adjustments. Never had this problem in C1 3, Obviously we must be missing a step in C1 4- but what? The iMac is regularly calibrated, the image looks great in the viewer (on screen) but is off in the levels. correcting makes the image appear two+ stops overexposed...
Any help or advice is appreciated, thanks.

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  Jonathan Gilbert

  • 2009年06月24日 14:25

  The first thing I will say is what you see is what you get, so in terms of exposure trust what is on your screen. The area where you want to pay close attention to numbers is concerning highlights so that they are not blown out going to print. Secondly, if you believe that the histogram is not accurately displaying the image, please create a support case and include the raw file as well as a screenshot of what you are seeing. We can then analyze what is going on.

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  Peter Walker

  • 2009年06月25日 15:54

  Jon, thanks for the reply. After much testing, it is in fact a monitor calibration issue that we have corrected. Interesting aside here is that we use an iMac (with the glossy screen) as our capture station, Then transfer the output files to a Mac G5 with two Apple Cinema HD monitors. We use Datacolor Spyder 3 calibration on all monitors and got different levels of screen brightness, which caused the images to appear over or under exposed- even though the histograms were correct. Comparing the Photoshop histogram to the C1, they appear the same, But the images were off due to screen brightness.
  
  One more question; When we process (output) files in C1 4, multiple copies are made- sometimes up to three copies of the same image. Is the a setting to have only one file processed?
  
  Thanks again-
  
  Peter

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  Jonathan Gilbert

  • 2009年06月25日 16:05

  Hi Peter,
  
  Just un-check the additional process recipes in the process tool. Every one that is checked will process. In terms of calibrating monitors, try lowering the brightness of the Cinema displays before doing the calibration. They can often be around 220-240 C/M^2 at full brightness, where as 120 (about 3/4 brightness if my memory is correct) is more ideal for accuracy.

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  Permanently deleted user

  • 2009年06月25日 16:29

  Hi Jon,
  is it possible to to make the process recipes unchecked as a default?
  If you have a lot of recipes (different clients, different needs) and you forget to uncheck the recipes you get a very busy computer ...

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  studio78

  • 2009年06月25日 22:03

  ++1 yes I agree, in terms of feature importance this may seem trivial but it's a nuisance to have to uncheck all the recipes which each new session, especially as for some reason we can't scroll the recipe window with the stylus we normally use here and have to reach for the mouse with the scroll wheel.
  
  Thanks,
  Dave

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