Also, my ISO800 files (posted earlier) has a properly exposed (according to ACR) shot, with clearly visible lines of magenta in the black bag (attatched with levels on top...) The image is unaltered, and opened with ACR where everything has been zero'ed.
I can't see any major problem here, Axel. Is this a storm in a teacup?
I don't see any magenta striping in the black bag when I convert in ACR, although there is a bit of noise in the darkest parts of the bag and a very slight magenta cast which is typical of deep shadows with my Canon DSLRs at any ISO.
If this sort of thing were going to be a problem in the final balance of the image, ie. if you wanted to really bring out the shadows, then just a little more exposure would probably fix it. As it is, you're using a pretty conservative ETTR in the shot with the greatest exposure out of the 3 bracketed shots at ISO 800.
I had a look at the specral highlights on the tangerine (after recovering highlights to the maximum in ACR) and they have a value around, 207,197,185.
I think you could probably have given that shot at least another 1/3rd of a stop more exposure.
The problem with ETTR as I see it, is it's better to be underexposed by 1/3rd of a stop than overexposed by 1/3rd of a stop. However, when bracketing exposures, one can afford to be less conservative.
Of course there are certain situations where bracketing is not possible as in the case of this shot of a Hill Tribe woman in Chiang Mai, taken with flash late in the evening. I made an assessment from the 5D's histogram that the exposure was probably okay. In fact, I believe there is slight clipping of highlights but nothing serious. However, I would have preferred a 1/3rd stop less exposure.
The default setting in ACR gives an impression the image is seriously clipped in the highlights. [attachment=4058:attachment]
However, just one click on the 'auto' button produces an almost acceptable result which looks hardly overexposed at all. [attachment=4059:attachment]
There's still scope in ACR to recover more highlight detail here. The brightest part of the image (apart from specral highlights) appears to be the yellowish tea shirt with a value around 207,197,185 after maximum highlight recovery. [attachment=4060:attachment]
Do you think this image is overexposed?