I have several old m42 mount lenses I rescued from the closet to try with my EOS 77D. I don't know what to expect from the rest but I am pleasantly surprised with this one. The first two were at 230mm at f22 and f5.6. The next two were at 90mm at f22 and f4.5. I like the difference of depth of field but I really like the quality from this old lens. I think they are all slightly underexposed and I'll remember that next time. Give me your thoughts.