I shot a 24 count roll of Fomapan 100 using my new (to me) Leica If. I used my Voigtlander Heliar 15/4.5 and an Orange Nikon filter. Here is where the problem was. I rigged the filter such that I sorta knew I screwed up the entire roll. It was too small and I used an adapter to pressure fit it within the little lens hood. Since I was sure the shots where messed up, I decided to see if my 3 year old Diafine was any good. I made it up in 2018, used it one time and stored it with the air squeezed out. Long story, short, the Diafine was FINE and all my shots have a black circle around the subject, thanks to my dumb filter idea. I tossed the Diafine and ordered some more and some 52mm filters. No sense in pushing my luck.