I've noticed that when I crop a photo, the histogram does not change. If I am then making changes based on the histogram (ie. exposure, fill light, blacks, etc...), it would seem to me that the histogram would be more useful if it was based only the area I had selected in my crop.
For instance, if the histogram indicates that I have blown highlights, or vastly underexposed parts of my photo, but I have cropped to remove those areas, wouldn't the histogram be more useful if it represented that?
Maybe I'm wrong, if so, please let me know why!
Thanks - Sean