Hi. This would make my first actually useful thread, in which I will show you how to repair this apparently very common issue with these lenses. As most Soviet lenses, these have way too much grease from the factory, which in time hardens and makes them very hard to focus.
This particular model has a very small design, which allows for a pretty nice lifehack actually: being so small, the focus helicoid protrudes at the rear and can be seen without disassembling the lens. What you have to do is pour 2-3 drops of lighter fluid on the helicoid threads, then twist the focusing ring so it gets uniformly down inside the lens, then remove the excess grease that is forming around the mount with a Q-tip. Repeat as many times as necessary, until the ring movement is as smooth as wished. Before, I barely could turn the ring with two fingers, now I can do it with one.
Last edited by vladimiroltean; 09-20-2012 at 03:37 PM.