Originally posted by ScooterMaxi Jim Hmm, I suppose they could be evolving with the design. I did notice just a bit of grit initially, but the damping is near perfect - very solid overall. I did notice that the helicoid is screwed in - have you tried hand tightening it?
Not sure what I could tighten. The focus ring itself can be pushed forward/back a bit, and when switching direction it will move the ring instead of the focus for a bit. But only sometimes. (But if I actually wanted to use a lens like this I should just buy a new one.)
Originally posted by ScooterMaxi Jim I had read about focus shift as you stop down (which is virtually a non-issue, as the plain c mount has no auto stop down mechanism). I would never leave focus to anything other than my last task in the routine. Most of my fast lenses have at least as much focus shift as this one - which is negligible on my copy.
You have so much light available. I often want to focus wide open (or close at least) to be able to see what I'm doing. (Of course with the ridiculous 2 second limitation I often can't usefully shoot at the aperture I would like anyway.)
The biggest problem seems to be around f/2.8, where it's actually quite sharp, but not if focused wide open. At f/4 it's ok again, as long as you only wanted what you focused on and stuff behind in focus.
Originally posted by ScooterMaxi Jim As for "pretty much what's available" on the diaphragm - it doesn't work that way. The construction has to be properly mated to the lens design - it isn't an off the shelf kind of match.
Why not? As long as it's the right size of course. The large format world doesn't seem to think you need specially mated diaphragms at least. (Of course it's more than the opening size that must match, but I still don't see a problem. Any other explanation for why your lens wouldn't match most of them?)
Originally posted by ScooterMaxi Jim Most of the 35 / 1.7s are, indeed, six blades on the aperture. Even the SLR Magic units are specified as six blades (at least the few references indicating that).
I'll attach an image of my diaphragm at f/4, maybe someone will enjoy that.