A brief summary of some lens hacking I did last night. I had found rff member Yavaro's engaging images on flickr made with the Industar-69 28/2.8 and was intrigued. A lens came to me yesterday attached to a broken Chaika II. It's an LTM lens, but w/o rangefinder coupling on an R-D1. My first images were awful, then I looked on the web and noted references to different registration distance for the Chaika than I would achieve on the R-D1. There must be some manufacturing variation with these lenses, or different flavors, as Raid here on RFF was able to get one working without mods. At any rate, google helped me find a comment by RFF member Brian Sweeney...
"I also make shims to collimate lenses. Lots of grinding. Converted an Industar-69 28/2.8 lens to focus on the Leica; had to file an internal stop off of the lens-mount."
...which then led me to another posting by him on another forum...
"The Focus ring comes off with three set screws. There is a raised metal ring in the alimunim mount that stops the helical from going to far in. I filed off about 1/2 of the thickness of that ring so the helical would keep on going. Used a through-the-lens viewer to get infinity- then put the focus ring back on. The only trick is to space the ring out a little bit so that the focus range goes from infinity to near, and does not get caught on the stop-pins. I just backed the ring out a few millimeters and tighted the screws. We're looking at 30 monutes of filing and hacking here."
Well it took me more than thirty minutes, and I had to file down all of that ring in order to get the helicoil to thread far enough into the lens body for infinity focus. This also mean that the lens assembly bottomed out on the stop-pins, so I removed them. Even had to grind down the focus ring some so it wouldn't bottom out. My pancake lens is now even flatter. I had no "through-the-lens viewer" so simply took shots with the camera at various focus positions, then shot some targets at measured 1 meter distance to callibrate the final assembly.
Below is an after (left) and before (right) combination shot. Not a very straight comparison as the after is on foggy morning vs the bright sun of the before shot. Focus is much better now, especially considering before was shot at f/8 or f/11 and after was at f/4.
First "real" shot was this morning on my bike ride to work. First truly foggy morning this fall in the east bay.
Thanks to all the RFF members whose comments helped me sort out my approach.