@James,
Thanks for the explanation, as mentioned in top of the test I never shot a situation as you describe and I can imagine it can drive you nuts.
On the 85mm 1.2L don't get me wrong I loved that lens, but the fall off at least for my eyes was completly different than what I'm getting with MF.
Not to say the Canon lens is bad or whatever it just looks different, and that's what I'm trying to explain all along
There is no simple way to compare the two systems because the sensor size is different.
The only lens that I use and own that gets close to the Canon 85 1.2 is the 110 F2 blad lens I stick on the Contax.
It does have a different look wide open but it's not that different than the 85 1.2 to the point I don't use it that much. It's just a pain manually stopping down and honestly compared to the Canons I don't use the medium format backs that much period, they're just slow and complicated and the difference, once an image goes through heavy post, is so small it's not worth the slowness in shooting.
When the conditions are right medium format can produce a great look, but they require a lot of light, tethering and I find the session begins to get stiff.
To segway this into the color thread that's started I find all the digital cameras to have a different look and I shoot a lot of them side by side, Contax to Leica, Leica to Canon, Canon to Nikon.
Right now I am processing 19,500 files from all four systems and even in the same conditions and lighting they look different and require a lot of adjustments.
Under certain conditions each one has a place, but they all render different color and contrast and then there is just some things digital doesn't do well.
I just shot in the Moscow train station, models backlit wanting that pretty flare you get from film and with digital it's just different. It's either blow out or softness or something but not that direct flare I use to get with film. And this is not just with the Canons or Nikons as I've tried this with the phase and leaf backs also.
Also I find all digital cameras to be very sensitive to ambient color, the Canons and Nikons less so than the Aptus and Phase digital backs I have owned. The canons can have their issues but so can the backs.
Shoot a digital back with hard light, like the profoto hard box and you will see a magenta banding on skin as it transitions from highlight to shadow. My Aptus 22 did this more than the phase even less with the Canons but they all do it to some extent. Consequently the Canons don't like shadow detail without pulling up clumps of noise, though a digital back, shot in continous light at high iso will also noise up in the shadow areas a great deal, to the point it takes a round of post work to fix it.
Also underexposing digital like we did film for that "look" is just difficult to do without a lot of post work and I find the post work in digital to usually be much more of a need rather than a want .
It doesn't mean film was perfect, but for a lot of subjects it was consistent and was kind of color dumb where it didn't see every bit of ambient color in the room.
Actually, maybe film was just smart and was engineered for a look rather than the way digital seems to be engineered to be color perfect.
I really would love for Kodak to go find those film guys that they probably layed off 5 years ago and hire them back to teach the sensor guys or the software guys how these sensors should perform, so we can build a cohesive look regardless of the ambient color or the light source.
Someone on one of these threads posted that Dubler link and his lighting and look is nice, but I found it interesting that he shot those images with an Olympus. Maybe it's because some sponsor deal with Olympus as it is mentioned on his site, along with Epson, but the images looked good and that is all that matters.