This is one of the later ZK Sonnars that I've seen. The Zeiss Serial Number stamped in the rear fixture shows it from a batch completed in 1946. The lens was in Contax mount. Adapting to the 1957 Jupiter mount was simple: one set screw holds the barrel in the Contax mount, barrel unscrews, and screwed into the J-8 focus mount using the same shims. Perfect Focus. The aperture ring required re-indexing, but the barrel came up exactly 1/3rd turn from original placement. Loosen the three screws, turn the aperture ring, tighten set screws. Not many are done so easily. Luck. The J-8 mount came out really good. Loads of old/dried grease, alcohol bath, Q-Tips, cloths, scrape grease with screwdrivers, and polish down the metal-to-metal surfaces of the mount with 3M fiber-optic polishing sheets. The Tabbed J-8 mounts are the best made, tightest tolerances.
The conversion is easily undone, the original mount is marked and stored with the set screw. I have an Amedeo adapter, and several of the inexpensive Chinese adapters. I prefer using Sonnars in a J-8 and J-3 mount.
The conversion is easily undone, the original mount is marked and stored with the set screw. I have an Amedeo adapter, and several of the inexpensive Chinese adapters. I prefer using Sonnars in a J-8 and J-3 mount.
