Hi All, I'm going to swap out the original Focotar 40mm on my Leitz Focomat V35 for a Schneider APO lens. I'm not concerned with preserving the autofocus really. What I do want is the best possible optical performance from my new lens. So should I go for the APO 50mm or the 40mm? I've read several posts talking about how the the APO Schneider is superior to the Focotar, but what about Schneider 40 vs 50? Thanks!