Rich, I had a 75/4 1:1 Apo Rodagon D. Veeery interesting MTF curves, I think they're on Paul Butzi's site. Flat to the edge. And past the edge the MTF goes to zero, as in no image at all. I think the lens is a wide angle with very restrictive field stops.
Anyway, according to Rodenstock it shouldn't be used far from 1:1. And at 1:1 it doesn't cover 2x3. So I basically gave mine to a friend who wanted it.