I have a number of Russian lenses that I like to play with on my digital M cameras. For whatever reason almost every Industar 61 that I've tried focuses properly for me. I suppose that the f2.8 max aperture covers the minimal back-focusing. At around $10 ea, it's worth buying a few and keeping the best. I gave the others away to friends to mess around with. Usually they just have sloppy or still focusing rings from old lube. They are sharp lenses, if rather boring in terms of character IMHO.
I've had to shim every Jupiter 8 that I've tried and it's pretty easy to do. I never bothered with reducing the FL for infinity.
I bought a Jupiter 3 recently from a seller in Russia that I assumed would need some adjustment, but it was dead on from 1 meter to infinity. The lens was mint condition as well. I wonder if it never focused properly on a Russian camera for the previous owner which would explain the mint condition. I won the Russian lottery with that one and it's one of the best FSU lenses that I have.
