After few months I managed to save some money for a used p20/1.7. I bought it in person and when I inspected it everything looked perfect - clear glass, no scratches, etc. Now I see that the the filter ring is somewhat loose and is flapping when I push it with my finger. This thing: Has anyone else expirienced something like it? How alarmed should I be? I could try to superglue it or something, but I am definitely worried it will do more bad then good. IQ-wise the lens seem perfect.