I picked up a 1958 Zorki 3C with a perfect-glass J-8 this month- with the intent to clean and shim the lens for Leica mount. Gave the focus mount the full works, including using fiber-optic polishing sheets for the finish and metal-to-metal movements. Came out really smooth. The Tabbed J-8 mounts with the three screws for the retaining ring holding the mount in are the easiest to work on, and come out the smoothest for operation. The tolerances are tighter than the 1960s lenses for RF vs actual Distance.
Got the lens shimmed for close-up, but would not focus past 10m. Th focal length was much longer than most, could not use on a Leica. SO- yesterday I used the J-8 mount for a Sonnar conversion. A very clean glass 5cm F2. Came out beautifully. Some pre-war Sonnars require you swap out the Aperture ring when screwing into a J-8 focus mount. This one did not. Once shimmed, re-indexing was simple: take out the longer set screws and use shorter ones. No need for Taps, the screws hold the mechanism against the underlying threads for the aperture ring.
Got the lens shimmed for close-up, but would not focus past 10m. Th focal length was much longer than most, could not use on a Leica. SO- yesterday I used the J-8 mount for a Sonnar conversion. A very clean glass 5cm F2. Came out beautifully. Some pre-war Sonnars require you swap out the Aperture ring when screwing into a J-8 focus mount. This one did not. Once shimmed, re-indexing was simple: take out the longer set screws and use shorter ones. No need for Taps, the screws hold the mechanism against the underlying threads for the aperture ring.
