Top tip for Lubitel users: I did find, with my Sputnik, that the lens elements are held in with circlips and that occasionally those circlips aren't tight enough, and the elements can wobble slightly, enough to detect with a gentle poke with a toothpick. So if you're not into the whole Lomography thing and you want your lens to focus where it's supposed to focus, then a tiny drop of superglue on the edge of the loose elements will help.