Jupiter-12 Kiev mount minimum focus distance

[PDA]

I recently acquired a Jupiter-12 35mm f/2.8 in Kiev/Contax mount for my Nikon S2. Unlike other reports on this forum and elsewhere, it mounts OK on my S2 without scratching the front plate. However, I am a little confused over the minimum focus distance. Some documentation online, including copies of the lens manual/brochure in Russian, state that the minimum focus distance is 1 meter, while other sources state 0.9 meters. The lens itself is marked with 0.9 m but when I rack focus when mounted on the S2 it's minimum falls between the 0.9 and 1.0 m markings. Is this limitation caused by the Jupiter's use on the Nikon? Any advice would be appreciated.

 

[TenEleven]

This happens because the incline of the helical of the Nikon is different to the Contax standard for which the Jupiter-12 was manufactured. (51.6mm standard focal length on Nikon vs 52.4mm standard focal length Contax). The Contax (and Kiev) helical rotates further out and would hit the 0.9m mark pretty much perfectly.

Also - even if the lens is calibrated perfectly there will be a focus error introduced due to this discrepancy which increases as you focus closer. It will not be a huge deal for a 35/2.8 lens, but wide-open close up you might notice it.

The 1m likely comes from the LTM, or more correctly M39 version of the lens which does focus to 1m only. The same caveats apply. Using a Russian Contax mount lens on a Nikon is the same as using a Russian M39 lens on a Leica.

 

[Sonnar Brian]

I recently acquired a Jupiter-12 35mm f/2.8 in Kiev/Contax mount for my Nikon S2. Unlike other reports on this forum and elsewhere, it mounts OK on my S2 without scratching the front plate. However, I am a little confused over the minimum focus distance. Some documentation online, including copies of the lens manual/brochure in Russian, state that the minimum focus distance is 1 meter, while other sources state 0.9 meters. The lens itself is marked with 0.9 m but when I rack focus when mounted on the S2 it's minimum falls between the 0.9 and 1.0 m markings. Is this limitation caused by the Jupiter's use on the Nikon? Any advice would be appreciated.

The J-12 is an external mount lens, and the rotation of the lens is limited by the rotation of the Nikon S-Mount. The Nikon mount does not rotate as far as the Contax mount. SO- use the lens on the Contax, it will go closer.