I acquired an "unknown" soviet lens off ebay, as a way to try new things. All I knew about it was its m42 mount. I didn't quite know what to expect until it recently got here. It has no markings. The lens has a working iris and nothing to focus. Come to think of it, either it is incomplete or that's some sort of projection lens. The barrel protrude beyond the lens and has threading on the outside, as to attach something else. If I hold the lens a few cm away from the camera I can achieve focus. I ordered a focusing bellows as a quick way to use the lens (still waiting on it) but would like to know of other options to adapt this into a useable lens. Any ideas greatly welcomed.