Jupiter-12 35mm M39

Jupiter-12 Leica Mt

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The most obvious choice for its own page, the Jupiter-12 is easily the most popular accessory lens for the Former Soviet Union Leica style rangefinders. They were produced over a period of years in a couple of different factories, this is the later black model from famed Lytkarino (LZOS) factory, who made lenses for KMZ.


The design is such that it’s self-shaded (no hood necessary), and the aperture ring is recessed inside the outer lens housing. Screwing a 40.5mm thread in means that the filter becomes your means for changing aperture.

The most difficult thing with the J12 is protecting the large mushroomlike rear element. It’s well known that minor scratches on the front of a lens have minimal affect on the picture quality; however scratches on the rear element, particularly one that comes as close to the focal plane as this one, are generally obvious on the final image. If yours didn’t come with a cap you might be able to make one out of a film canister.

Because the rangefinders you will use this on have viewfinders that are designed for the angle of view of 50mm lenses, you will need a special viewfinder to put in the accessory shoe in order to properly frame your subject. Focus in the window as normal, frame in the accesory finder. I use a Petri finder, it’s close enough to 35mm to be very useful. If you have more than one auxiliary lens it’s probably best to get KMZ’s Zeiss copy multi-finder.

FED 3 Finder

Special Notes

Occasionally the rear element rubs on the inside of the camera, most noticeable when mounting. Always mount these lenses by first changing focus to infinity to flatten the base of the lens housing. If you feel some resistance when screwing it in, stop, remove, and check to see if it’s rubbing on the rangefinder arm. You may lose paint from the edges of the rear element, resulting in flare. I did this the first time I mounted mine, and repainted it with flat black paint pen from Birchwood-Casey. Then I bent the rangefinder arm upward slightly on that particular FED 2 (they’re all just a little different) and made sure to always set focus to infinity before mounting it after that.

NOT COMPATIBLE with the Bessa rangefinder series, from what I understand; the rear element interferes with the shutter on those cameras. Common question.

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