Quote Originally Posted by jbbooks View Post
Let’s see—if you go to the following link, you will find an information chart for Schneider lenses. The chart lists eleven different centerfilters made by Schneider for use with their Super-Angulons, older Super-Angulons and for their Super-Symmar Aspheric lenses. There are no centerfilters recommended for use with their APO-Symmar lenses.

https://www.schneideroptics.com/pdfs...LensCharts.pdf

So, according to your logic, Schneider does not recommend centerfilters for those lenses that really need a centerfilter, but does recommend them for those lenses that do not need them so much.
Well a lens like the Symmar drops off at cos^4 and the Super Angulon drops off at cos^3. So I would say that a 120mm Super Angulon would have less fall off at any angle off the center line. Center filters aren't used on Symmars because they don't have the kind of wide angle coverage that would need them. They only cover 72-75 degrees compared to the 100 or so for the Super Angulon.