Leica Carl Zeiss Jena 5cm f1,5 Serial Number Check

Michael Finder

New Member
Hello, I have a wartime CZJ Sonnar 5cm f1,5 in Leica Thread Mount serial # 2870001 which seems to date it approx. from 1942. I need advice on how to unscrew the optic module to check for matching serial numbers and perhaps determine it's authenticity. I am loathe to dismantle/damage the lens due to ignorance.

I have scoured threads on other forums and nothing seems to answer my question.

Thanks Michael.
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The optics should simply unscrew UNLESS someone has cemented the barrel into the focus mount. The front ring "might" have a hidden set screw, same with the rear optics- they might have a hidden set screw. I had a thread up on the old Zeiss Ikon site, long gone.

This is a transition lens, genuine Zeiss Optics, Genuine Zeiss focus mount and barrel, most likely assembled after the War in what remained of the Zeiss plant. I have one just like this one, when received the middle triplet was uncoated and "roughly polished". It was slightly before yours. I replaced the middle triplet with one from a Zeiss parts lens.

If the optical barrel cannot be unscrewed easily, the lens can be disassembled from the "outside in". I just had to do that with a 1957 J-3, and have done that before with these transition lenses.

Shown is my wartime Sonnar, 272 block. I also have a 285 block lens and 286 block "transition lens". And two 1950 Jupiter-3's with Zeiss glass and parts, SN stamped into them. And a 1949 ZK lens, Zeiss parts assembled in Russia. I've disassembled dozens of these lenses, the transition lenses are almost "one-offs". Most are very good optically.

See this flickr album:

1943 Carl Zeiss Jena Sonnar T 5cm F1.5

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retaining_screws by fiftyonepointsix, on Flickr

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start_like_this by fiftyonepointsix, on Flickr

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helical_sn by fiftyonepointsix, on Flickr

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stamped_rear_sn by fiftyonepointsix, on Flickr

brass_shim_one_piece by fiftyonepointsix, on Flickr

The aperture ring must be removed to examine for a hidden set screw holding in the front namering. I found out the hard way with a $35 Sonnar.
 
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I uploaded the pictures taken of my 285 block (late wartime) 5cm F1.5 Sonnar.

It is close to yours, note the black finish on the filter ring.

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czj2_after_side_2 by fiftyonepointsix, on Flickr

Late Wartime CZJ Sonnar, 285x

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czj2_before_2 by fiftyonepointsix, on Flickr

This lens was a mess. Before and after shots marked in the titles of the pictures.

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czj2_helical_3 by fiftyonepointsix, on Flickr

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czj2_helical_after_2 by fiftyonepointsix, on Flickr

Lots of time in a ultrasonic cleaner...
 
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by fiftyonepointsix, on Flickr

IF there is a hidden set screw holding the namering in: you must teardown the barrel to this stage to find it. Zeiss started using the hidden set screw Around SN 267xxxx. They seem to drop off after SN 286xxxx. I would not attempt to remove the namering on yours until checking. My 285x lens had it in place on the front namering and rear fixture. My 286 block lens did not have it.
 
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