Thank you very much for your response mmost. Very informative. Of course, every answer leads to more questions...
I guess my question then is does Dmin to Dmax on a Spirit 2/4k go as high into the brights and and as low into the darks as an Arriscan (with it's 2-light system)? Or am I drinking Arri's PR?
Also:
Obviously I wouldn't want to use that flat image for final, I'd color-grade it to be more contrasty. Now, if I take an image into photoshop and look at the histogram I'll get a nice full curve of information. (follow me here...)
I then lower the contrast in the image using level. Then I open the levels adjustment and increase the contrast again to make it look the same. When I look at the histogram, the curve is the same, but now it's full of gaps.
Now, I can't tell the difference with my eye between the image I started out with and the 'processed' image, but it looks like I'm losing shades of 'color'? 'luminance'?.
Isn't the same thing happening if I scan Dmin-Dmax and then boost the contrast in the colorgrade? Or is this information that doesn't really affect the image quality? (like I said, I can't see the difference).