Hi Paul
This is interesting stuff and is showing me I have a bit of a sketchy grasp on the histogram, especially as displayed by DSLR’s.
I thought that the histogram was a representation of the range of brightness levels (0-255) across the bottom axis (X-axis) and a representation of how many pixels of intensity “n” fell into each brightness level (Y-axis).
So,
- A big hump in the middle would indicate lots of pixels (high ADU count?) in the mid-gray range.
- A big hump on the right would indicate lots of pixels at the white end.
- A big hump on the left would indicate a lot of pixels at the black end.
So, this gave me the understanding that the height of the histogram was a representation of the quantity of pixels which were “held” in each brightness level bucket. If that is the case, the Y-axis would then be a sort of ADU measure?
Cheers
Dennis