I've been thinking about this issue at some length and I am trying to get my head around your assertion that the change in question is necessary to ensure accurate per-channel black level calculation. Surely if you apply the per-channel calculation to the "image" area using the correct filter mask for that, then it will all be correct? I can see that if you applied the "image" area filter mask to the whole RAW including the frame area then things could go awry. But you know better that to make that error.
So please explain why you believe my reasoning is incorrect.
Alex,
I've been thinking about this issue at some length and I am trying to get my head around your assertion that the change in question is necessary to ensure accurate per-channel black level calculation. Surely if you apply the per-channel calculation to the "image" area using the correct filter mask for that, then it will all be correct? I can see that if you applied the "image" area filter mask to the whole RAW including the frame area then things could go awry. But you know better that to make that error.
So please explain why you believe my reasoning is incorrect.
Thank you