What lens mount it is?

I have two adapters (both were the "almost cheapest ones") from m42 to nex. One of them is designed wrongly and does not allow infinity focus (lens to far from camera). Look for something with a ring inside that will press down that pin. Otherwise the lens will most probably stay wide open (aperture controls will not work). As we are talking about 20-30$ investment - give it a try, seems like a nice lens (if it's working properly- which you can check without a camera).