Leica Carl Zeiss Jena 5cm F2 Sonnar, 1934, adapted to Leica Thread Mount

This lens started off as a collapsible lens for the Contax RF. Converted to Leica mount using a Jupiter-8 focus mount. This is an uncoated lens, lower contrast. This is the first time on the M Monochrom. This lens was MADE for Black and White.

All wide-open at F2.


This lens was old when the P51B was new.


I'd be ready to board this JU-52 with my Contax II and this lens.
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Great shots, Brian. These images have a tonal range that is very pleasing to me. They are obviously very well composed. Thank you for sharing them.
The Jupiter-8 and Jupiter-3 are Thread Mount. The threads for the optics modules are the same as the Contax mount lenses, and the shims are the same. The aperture ring of the J-8 takes the place of the one on the Contax mount lens.
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Great portrait of your daughter, and the museum shots also very nice. The low contrast working very well here.


Bakersfield, CA
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Especially on the M Monochrom. I don't have to underexpose to preserve the highlights when shooting the Sonnar like I do with modern glass, and the tones and rendering really give a magical look.

You can keep "Leica Glow", these Sonnars have their own magic pixie dust.


Bakersfield, CA
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There is an 80-year-old woman in my Rotary who will have me photograph her granddaughter, wearing her (the 80-year-old's) 1915 bathing suit with 1915 hairstyle. My 1937 Sonnar is a bit too modern, but I'm still confident we can make a fantastic 1915 portrait.
This is what went into disassembling a 5cm F2 Sonnar and converting to LTM. The one here is from 1940, and is a coated "Sonnar T"

The thin copper shims are about 0.02mm thick, I use a very small screwdriver to work it over the threads. It is thinner than you really need for nailing the focus, you will probably be re-using the thicker shims and cutting some aluminum foil.

Any Jupiter-8 LTM focus mount will work. Most likely, you will need to swap the aperture rings as well. Remove the retaining ring, which is held in with a set screw, and take out the coupling screw that holds it in place. The later Black focus mounts are more reliable, have less slop in the helicals, and are easier to work on. The early aluminum ones with the Tab are usually better made than the 1960s aluminum J-8's.

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while I'm at it...


The namering is held in with two set screws. these come out, the front element and front triplet come out. The rear doublet simply unscrews.


The black paint was coming off of the triplet and the rear doublet, I used a Black Sharpie to replace it. Works well.
And the finished lens with the "left-over" parts. I'll use the glass in the Jupiter-8 optics to repair another lens. The J-8 optical fixture is a different shape and will not fit into the collapsible mount.


This lens is on it's way to a Leicaplace member.
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Is that what my 1941 T Sonnar looks like?

That's the one! I disassembled it, gave it a full CLA- wanted to document the breakdown.

On the Shims- once the optical fixture is in the new mount, the lens must be shimmed for correct focus. This means new shims, which can be made from aluminum foil, old retaining rings, etc. The thickness is critical, this one's final adjustment was to within 0.01mm for the final. You can use the retaining ring for the aperture ring as a variable stand-off ring, unscrew it a fraction of a turn as required and then make a new hole for the set screw.
I'm reviving this thread on the 1934 5cm F2 Sonnar converted to Leica mount.

Skyllaney now offers this service, and will be introducing a new 50mm F2 Sonnar formula lens. That lens is based on the same formula as this one, and I'll be testing the two lenses together in a few months. I've been going though old and new albums for this lens.

I think it was very wise of Skyllaney to come out with the 50mm F2 Sonnar. The originals use soft glass for the front element, finding a clean one is very difficult. It's like finding a clean Summar. Right now I have Six 5cm F2 Sonnars, this 1934 lens has near-perfect glass. I have a second one that has all repolished and coated surfaces- it is also perfect. I have that one shimmed for S-Mount and on my S3-2000.

These are at F4, on the M9.

This one is the strong backlight test. This is an uncoated lens.

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