Also check the Pentacon 50/1.8 thread for the latter incarnation of this lens. I started using the Oreston on MFT. Very good performance, even wide open. The following is taken around f/4 close to minimum focusing distance (33cm): This is the best Meyer Optik lens that I used so far and looks like a top 50mm lens. Much better than the Domiplan 50/2.8 or the Pentacon electric 135/2.8.