Thanks for that experience. I have been trying it at f/16 and am still fiddling with it. A while back, you detailed how to make an F-mount for this lens out of odds-and-ends. I did that, but for some reason when I put it all together it puts pressure on the aperture slide so that it locks up and does not move. If I start to unscrew the mount, then it will move, but is loose. It looks like I must need a slight amount more of room, a shim or something, but have been unable to figure what will work. Any ideas?