The CV15 works fine on my FSU bodies (Zorki and FED), although the screw thread aligns slightly off on some of them so the "hood" isn't in quite the right position. After I first got it I put a few test shots in my gallery,
here
Those shots were taken with a Bessa-L, and The 15 and the L were all I had in the RF world then (the L isn't an RF, but you know what I mean), and I had no intention of getting anything else in the RF line - ah, such naiveté
🙄