I think you may be right Roninman.......is the lens spec design a Plannar (double guase sp?) design?
yes, the Nikkor is a traditional 6/4 (elements/groups)
The Summicron R v1 is 6/5
The Summicron DR is 7/6
And the 50MP is 8/6
the most complicated design I know of for a 50/2 is the Zuiko 50/2 which is 9/7, and the new APO Summicron is 8/5. The MP, Zuiko and APO Cron have a floating lens group. The others do not.
the only non-planar ~50mm lenses I know of is the Takumar 58/2, everything else is either a derivative or a telecentric modification. I cannot confirm this information though, I dont know every ~50 that's ever been made. Even the Xenotar derivatives are just going off Schneider's take on the planar design.
ps I just wanted to say that I wish MTF graphs had some sort of standard that makers had to adhere. Frankly, Zeiss' would be fine, Leicas a little less so but still.
anyway, this is the MTF graph for the 50mm Makro Planar at infinity at f5.6:
it's currently the only 50 in the world in the same conversation as the 50APO (new Zeiss 55 distagon isnt out yet, of course) and as we can see on APX100 you're going to struggle to see it do much better than a $50 Nikkor. It would be mighty interesting to see this test done with micro or technical film. If Canon ever bothers to push out a high MP body I may rent one to test out some lenses.