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Author Topic: C1-5--Why is the output histogram different from the RAW histogram?  (Read 5851 times)

robgo2

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I have noticed that the histograms of output images (TIFFs or JPEGs) have significant clipping of shadows and highlights that is not present in the RAW image.  I must admit, that the images look very much the same, but this seems to be a strange behavior.  It does not happen with Lightroom, whose images exported to Photoshop have essentially the same histograms.  Am I doing something wrong in the Processing step?

Rob
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tho_mas

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C1-5--Why is the output histogram different from the RAW histogram?
« Reply #1 on: December 28, 2009, 05:59:00 am »

Quote from: robgo2
I have noticed that the histograms of output images (TIFFs or JPEGs) have significant clipping of shadows and highlights that is not present in the RAW image.  I must admit, that the images look very much the same, but this seems to be a strange behavior.  It does not happen with Lightroom, whose images exported to Photoshop have essentially the same histograms.  Am I doing something wrong in the Processing step?

Rob
user error.
C1 always shows the histogram of the selected output profile (unlike Lightroom that doesn't show any usefull histogram / RGB-data).
Make sure that view->proof profile is set to "selected recipe".
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robgo2

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C1-5--Why is the output histogram different from the RAW histogram?
« Reply #2 on: December 28, 2009, 10:55:32 am »

Quote from: tho_mas
user error.
C1 always shows the histogram of the selected output profile (unlike Lightroom that doesn't show any usefull histogram / RGB-data).
Make sure that view->proof profile is set to "selected recipe".

Thanks, I will check that out.

Rob
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madmanchan

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C1-5--Why is the output histogram different from the RAW histogram?
« Reply #3 on: December 28, 2009, 02:21:32 pm »

Output histograms are of the rendered output-referred data, as opposed to raw histograms which are of the unprocessed scene-referred data. For example, if you took your raw file and set the Exposure slider all the way to the right, making your image appear completely white, you'd expect the resulting "output histogram" to be bunched up all the way to the right, since it's reflecting the huge Exposure bump that you made. It would naturally appear very different from the original raw histogram which doesn't incorporate your adjustment.
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Eric Chan

robgo2

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C1-5--Why is the output histogram different from the RAW histogram?
« Reply #4 on: December 28, 2009, 02:32:52 pm »

Quote from: madmanchan
Output histograms are of the rendered output-referred data, as opposed to raw histograms which are of the unprocessed scene-referred data. For example, if you took your raw file and set the Exposure slider all the way to the right, making your image appear completely white, you'd expect the resulting "output histogram" to be bunched up all the way to the right, since it's reflecting the huge Exposure bump that you made. It would naturally appear very different from the original raw histogram which doesn't incorporate your adjustment.

Eric,

I was referring to the difference between the adjusted RAW histogram and the output histogram.  What puzzles me is that even though the output histogram shows signficant clipping of shadows and highlights, I cannot see any difference between the output image and the adjusted RAW image

Rob
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tho_mas

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C1-5--Why is the output histogram different from the RAW histogram?
« Reply #5 on: December 28, 2009, 04:39:50 pm »

Quote from: robgo2
What puzzles me is that even though the output histogram shows signficant clipping of shadows and highlights, I cannot see any difference between the output image and the adjusted RAW image
That's indeed strange.
Care to outline your color managment settings, i.e. which color space is selected as output profile in C1 and how did you set your color prefs in Photoshop?

edit: another thing to consider - clarity and sharpening is NOT reflected in the histogram of C1.
So if you set a high amount for clarity and/or sharpening that may result in clipping (but IMO actually only slight clipping).
« Last Edit: December 28, 2009, 05:35:04 pm by tho_mas »
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robgo2

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C1-5--Why is the output histogram different from the RAW histogram?
« Reply #6 on: December 31, 2009, 05:19:17 pm »

Quote from: tho_mas
That's indeed strange.
Care to outline your color managment settings, i.e. which color space is selected as output profile in C1 and how did you set your color prefs in Photoshop?

edit: another thing to consider - clarity and sharpening is NOT reflected in the histogram of C1.
So if you set a high amount for clarity and/or sharpening that may result in clipping (but IMO actually only slight clipping).

I set Clarity at 50 and used the default Sharpening settings.  Perhaps that explains the phenomenon.  As I mentioned earlier, I cannot visually perceive a difference in the RAW and Output images.

Rob
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