Alan, I don't know how much research you have done, RE: digital cameras, histograms, and overexposure warnings (aka blinkies, aka zebra stripes), but I'd want to know a lot more about what, exactly, the digital camera is programmed to tell you. A full discussion should probably be started elsewhere, by someone who has a lot more knowledge than me, but:
- When a specification is quoted for the "sensor dynamic range" I believe that would apply to the RAW file, right? YES
- And doesn't the histogram/overexposure warning apply to the JPG, and not the RAW file? YES
- Since the histogram represents the JPG, which has a color profile applied to it in the camera, choosing a different color profile can make the blinkies appear or disappear without changing the exposure. YES. SEE BELOW
Each camera manufacturer may have a slightly different goal in mind when creating the algorithm that triggers the overexposure warning. Are you warned when any one color channel is clipped, or only if all three are clipped? TWO CHANNELS REQUIRED Do some camera manufacturers add a safety factor? YES I READ ONE MANUFACTUER ALLOWS ABOUT 1 STOP MORE WITH RAW OVER THE CLIPPING BLINKIE WITH JPEG. How does the algorithm treat specular highlights? I don't know. sPECULAR HIGHLIGHT WILL BLINK. BUT YOU KNOW THAT BECASUE YOU SEE THE RED BLINKIE HIGHLIGHTING THE SPECULAR LIGHT. YOU WILL SEE THAT IN THE HISTOGRAM. BUT IT DOESN;T INDICATE WHICH PART OF THE IMAGE IS CLIPPING. THAT'S THE PURPOSE OF THE BLINKIE. THE PART OF THE IMAGE THAT IS CLIPPED START TO BLINK IN RED. BLACK CLIPPING BLINKS IN BLUE.
I think this approach is more likely to lead to predictable exposure results than trying to measure and understand the relationship between clipping in digital cameras and analog exposures.