Some answers.
When opened in Rawnalyze, the DNGs, but not the CR2s, show "+1/3" left of the lightness slider. The Rawnalyze histograms of a gray card however look exactly the same for both CR2s and DNGs.
Rawnalyze
blindly shows the exposure adjustment dictated by the creator of the raw file, in this case by the Adobe DNG converter. This adjustment usually reflects the difference between the camera maker's and Adobe's interpretation of the ISO standard.
The
raw histogram displayed by Rawnalyze is absolute; it reflects the unadjusted raw pixel values. Only the scale underneath depends on the top saturation level, which is fixed for the camera and the ISO (like 16383).
NOTE: the mapped histogram is
only for educational purpose, i.e. for the demonstration of what is happening there, particularly when discussing ETTR. Neither demosaicing, nor color space conversion (from the camera's color space to whatever) took place before calculating that histogram. Accordingly, the effects of the contrast and saturation adjustments are not reflected in the mapped histogram.
So...the only finding that I can immediately use is the highlight warning
You mean the clipping warning, right? That's how it should be.
The entire concept of metering and of headroom in highlights and footroom in shadows are the worthless leftovers of the film era, for the reassurance of dynosaurs.
There is no such thing as headroom and footroom with raw processing. The raw data is absolute, and you can put the head and foot wherever you want to. This is particularly relevant with ETTR: you are striving to eliminate the headroom in order to lift out the shadows from the noisy region.
How does the +1/3 come in, which is shown by the Rawnalyze lightness slider? In which direction does it go? How does ACR handle this?
The 1/3 reflects ACR's rendering. +1/3 indicates, that ACR will apply a +1/3 EV adjustment to the "exposure" slider (but it is not shown on the slider!!).
***How can I achieve an exposure that renders D 0.7 as D 0.7 ?***
I know it is not nice to say so, but the question itself is wrong. The goal of raw conversion is not to render D 0.7 as D 0.7 (if you are expecting that, then go with JPEG). Initially, it should show
how the shot is on its own, i.e. without faking exposure, ISO, etc. From that point, you should decide what to do. Adobe's misunderstanding of ACR's role is becoming apparent here: they think they are supposed to "correct" the shot automatically, instead of helping you in processing it
If you underexposed the shot, then it is underexposed. Basta. If you have blown the highlights, then they are blown. Basta.The raw processor is not supposed to make an experienced photographer from someone, who does not understand his DSLR. P&S cameras are supposed to do that.
And why are the RGB values so way off?
Pls describe it better, what you mean; this is an important issue.
Sigh...
The questions indicate, that this is not so bad.