Originally posted by Toolmaker This is just an update into my Tukamar m42 500mm F4.5 lens adventure:
Well, I finally got it up and working! It took persistence and some face time with Fred at Universal Photographic in Kalamazoo, MI. He sat down with me and explained the theory behind the focus mechanism and from there it was just commitment. For this particular lens you want to have the helical splines engage in order to have the shortest overall length to enable focus past infinity. I had discovered the "person" who previously worked on this lens had engaged the helical two splines off that prevented focusing past Infinity. Once that is done it's just a matter of reassembling and focusing at infinity (the moon for me) and noting the amount of rotation from the hard stop and then making that adjustment. For me I was able to add a k-mount adapter (the one WITH the flange) from GOBE and still have plenty of room to focus past infinity by about an 1/8" looking at the markings. (the GOBE adapter stays with the lens and mounts like a regular K-mount lens - nice) I am not going to set the hard stop until I use it enough to know that's where it should be with both my bodys and teleconverter. So there you have it. One final word. If you add an adapter to your old screw mount and cannot focus to infinity there is adjustment that can be made to the stop and worse case you have to dig down to the helicals and change the engagement.
Nice description of how the system works, I have the older 500mm with the rack and pinion focusing, however I have spotted a slightly fungus affected one like yours and I think I will give it a try
Thank you