Just wanted to make a post about this excellent lens. It can be picked up for very cheap and often comes with the viewfinder for those using it on screwmount. I use it on my IIIc, but it can be easily adapted to an M body. Construction is very solid, and the lens performs almost flawlessly at f4 and up. Here are a few pictures at F-2.8 on Tmax 100. Notice in the image with the girl and the cellphone, the softness at the very edge. The next inner zone is sharp and then even further inward gets radial again. The very center is VERY sharp for a 1951 japanese lens. Highly recommended.