Image histogram generated from what data?

out of curiosity, is the histogram for a dslr image based on the RAW file or a compressed jpeg like backyard EOS??
I ask as id like to use the histogram to work out my flats exposure as I don’t know how to work out the ADU for a dslr.
Also is it possible for the histogram to show the colour channels for a dslr/OSC camera??
as its the red channel that is potentially the problem.

It is based on the raw data returned from the camera that has been scaled to 16bit.

For the ADU use the normal rules for CCDs. Set the peak somewhere between 20k-32k for flats.


Thanks Jared
Ill give the 20K-32K a go in the flats wizard in that case.

I hadn’t realized that DSLR data is scaled up to 16 bit. That’s good to know.