Originally posted by Class A There is a Green/Magenta slider in the camera calibration tab that can be used to address this issue.
One method to address it is to tune camera calibration indeed. If that was the cause.
In many cases, it doesn't seem to work though.
An application of split toning with carefully chosen parameters seems to be the best cure then.
I tend to believe that the black clipping levels are part of the problem. But I am not sure.
Originally posted by sTi What's the technical reason for this magenta shift? Is it really a sensor-specific problem or could it also be a software Raw processing or camera color profile issue?
It must be a combination of reasons. The magenta shift in Nikon D4s JPGs at very high iso is much reduced vs. D4. Therefore, I assume it can be taken care of by proper processing.
However, many believe the root cause to be amplifier glow. At least, amp glow always appears in magenta color indeed.
E.g., the D800 sensor has minor amp glow in the bottom third of it.
Personally, I believe it is a bug in color processing in all cameras / raw converters where the hidden assumption is being made that all signal is from photons. Where in fact, some signal is from averaged noise. Dark frame subtraction typically helps here, without addressing the real issue.