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General Chat / What does the Canon Luminance Histogram actually show?
« on: August 25, 2023, 10:53:56 AM »
Might be a bit OT but I think maybe someone here knows this from reverse engineering... This is actually a cross post from here: https://photo.stackexchange.com/questions/132339/what-does-canons-brightness-histogram-actually-show I posted also some images there.
I wondered what the luminance/brightness histogram of Canon cameras actually show (in my case a Canon RP).
I tried to replicate the histogram from the embedded JPG of RAW files and it matches the RGB histograms quite nicely but the luminance histogram looks different.
I know that the histogram is some kind of weighted RGB sum, but what exactly Canon does I have no idea.
What I find interesting is, that the histogram on the camera has these spikes - which I think are from integer calculations and binning artefacts. I could see similar things if I only used 6 significant bits for the calculation.
I wondered what the luminance/brightness histogram of Canon cameras actually show (in my case a Canon RP).
I tried to replicate the histogram from the embedded JPG of RAW files and it matches the RGB histograms quite nicely but the luminance histogram looks different.
I know that the histogram is some kind of weighted RGB sum, but what exactly Canon does I have no idea.
What I find interesting is, that the histogram on the camera has these spikes - which I think are from integer calculations and binning artefacts. I could see similar things if I only used 6 significant bits for the calculation.