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in a mount fitting the Leica and with thread M 39x1

Historical reference by Jenoptik

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Howard Lewis14/09/2021 16:08:46
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At the risk of adding confusion, 26 tpi has a pitch of 0.97623 mm, differing from 1 mm by 0.023. (23 microns ), or just less than 0.001"

Maybe if the 39 x 1 thread was produced slightly undersize, for the very short thread engagement involved, the difference in pitch and form MIGHT not be too noticeable, as long as the register distance was maintained .

But am surprised that, PRE WW2 Zeiss should produce 39 x 1 rather than physically checking a Leica thread.

Post WW2, one could possibly understand Jena following the lead (edict? ) of Russia in using 39 x 1 like the Fed, but prewar seems unusual.

Even more intriguing is that so many other makers of lenses and accessories (LDB, Corfield and Kopil to my knowledge ) did not check and accurately copy the Leica. Maybe, they all assumed that because the OD was 39 mm the pitch would be 1 mm, because it looked like it, without checking pitch or form?

Those who would have known are no longer with us to tell.

Howard

Edited By Howard Lewis on 14/09/2021 16:09:48

KEITH BEAUMONT14/09/2021 17:01:04
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37 photos

Howard, Sorry, I quickly read the figures as 0.977"!

Michael. Their is no doubt that several Fleet street Photographers, in the 50s had a Zeiss Sonnar converted to Leica 39mm mount. In fact one of these is on Ebay at the moment for £3889. if you want to buy one. Bert Hardy was one of those. I have his life story where, I am sure it is mentioned that he had one converted. I attended a lecture given by him and he made referance to it.. I am at the moment speed reading it,to see if I can find a quote.

Keith.

Michael Gilligan14/09/2021 18:25:35
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Thanks for the ‘lead’ Keith … but, no, I’m not in the market for one sad

and anyway … My academic interest is solely in the pre-war batch that were made by Zeiss with the ‘mount fitting the Leica’ not any later conversions. According to Herr Gessinger, it appears that these were all 5cm f1.5

To be honest, I doubt the veracity of his statement that these had ‘M 39x1’ threads … but the truth would be revealed if only we could measure [or see a decent photograph of] an original item in pristine condition.

MichaelG.

Nick Clarke 315/09/2021 13:07:13
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1253 forum posts
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Michael - have you seen this?

**LINK**

Michael Gilligan15/09/2021 14:06:13
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Posted by Nick Clarke 3 on 15/09/2021 13:07:13:

Michael - have you seen this?

**LINK**

.

No I had not seen that page, Nick … so: Many thanks for another interesting snippet yes

Unfortunately it adds nothing to my understanding of the simple-but-frustrating issue of the screw thread mis-match.

There are a lot of fakes around, and since the Jenoptik letter only recognised production of 5cm f1.5 Sonnars “with mount fitting the Leica” I am concentrating my attention on trying to understand those.

Admittedly … I may never find the truth

MichaelG.

Neil Wyatt15/09/2021 18:23:50
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Posted by KEITH BEAUMONT on 14/09/2021 17:01:04:

Howard, Sorry, I quickly read the figures as 0.977"!

Michael. Their is no doubt that several Fleet street Photographers, in the 50s had a Zeiss Sonnar converted to Leica 39mm mount. In fact one of these is on Ebay at the moment for £3889. if you want to buy one. Bert Hardy was one of those. I have his life story where, I am sure it is mentioned that he had one converted. I attended a lecture given by him and he made referance to it.. I am at the moment speed reading it,to see if I can find a quote.

Keith.

Yikes!

My Zeiss Sonnar is an exceptional lens, but I think its value is in two, not four figures - regardless of any mount modification!

Neil

Neil Wyatt15/09/2021 18:28:12
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Posted by Bob Stevenson on 11/09/2021 21:35:20:

Carl Zeiss Jena,...or, in common parlance, 'East German Zeiss' made the lenses for the Pentacom 35mm SLR...the standard lens was the 58mm Biotar, if I recall and, I think used a 39x1 thread. This was later crudely copied by the Russians in the Zenith SLR which also used 39x1 and the Biotar(?) was the origin for the Helios 58mm lens.for that camera.

No, they used M42 x 1, the same as Pentax.

Note that T2 thread is M42 x 0.7.

There was nothing crude about the Helios 58mm, it's an excellent bit of glass.

Neil

Michael Gilligan15/09/2021 18:31:52
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Posted by Neil Wyatt on 15/09/2021 18:28:12:

.

Note that T2 thread is M42 x 0.7

.

… or x 0.75 if you look a little more carefully angel

MichaelG.

Howard Lewis16/09/2021 06:28:55
5298 forum posts
13 photos

0.75 mm seemed to be the standard pitch for screw in filters.

Once I bought a wide angle lens with a damaged (dented ) filter thread. A fellow member of the photographic club,(an instructor inn the C A V Training School ) made up a partial male thread so that I could do some "panel beating" and restore the thread thread to be useable.

After all these years, I don't know what happened to the "repair" kit!

Howard

Clive Hartland16/09/2021 08:14:16
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The Pentacon 58mm Biotar lens was and excellent lens, I used to use it as an enlarger lens as well. The lens configuration was that the lens in the body were the same both ways, thereby correcting any errors. Very good for B & W pictures.

Nick Clarke 316/09/2021 08:41:20
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Posted by Neil Wyatt on 15/09/2021 18:28:12:
Posted by Bob Stevenson on 11/09/2021 21:35:20:

Carl Zeiss Jena,...or, in common parlance, 'East German Zeiss' made the lenses for the Pentacom 35mm SLR...the standard lens was the 58mm Biotar, if I recall and, I think used a 39x1 thread. This was later crudely copied by the Russians in the Zenith SLR which also used 39x1 and the Biotar(?) was the origin for the Helios 58mm lens.for that camera.

No, they used M42 x 1, the same as Pentax.

Note that T2 thread is M42 x 0.7.

There was nothing crude about the Helios 58mm, it's an excellent bit of glass.

Neil

The later Zenit SLR cameras did use the M42 mount, however the earlier Zenit 3m used M39 but with a greater film/lens distance to allow room for the mirror etc in an SLR. The Zeiss Biotar copy, the Helios 44 58mm f2 was available in this registration, but while this will physically fit a rangefinder camera there is no cam to operate a rangefinder and it will not focus.

KEITH BEAUMONT19/09/2021 12:33:11
149 forum posts
37 photos

Michael,

I have contacted one of the leading dealers in classic cameras regarding this question and he has sent me several pages of a reference book on the subject of Leica thread Zeiss lenses.The problem is my lack of ability to put them on this forum. If you message me with your e mail address I can then forward them to you and you can decide whether they can be displayed.

Keith

Michael Gilligan19/09/2021 16:56:17
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Many thanks, Keith … Personal Message winging its way as soon as I have posted this

MichaelG.

Michael Gilligan19/09/2021 20:29:32
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18926 forum posts
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With enormous thanks to Keith and his contact … We have something reasonably approximating hard evidence:

.66a232d0-250a-41c2-88dd-e37a9d058e37.jpeg

.

c64da24e-885a-4c63-b5b9-068630f19fbf.jpeg

.

c58b1637-bbe2-4d6c-a791-445f05a43efb.jpeg

.

That Biogon is Wartime issue, so a little later than the ‘Holy Grail’ pre-War 5cm 1.5 Sonnar … BUT we do have a photo of the mount : It’s still not definitive, but it does look like a Whitworth thread-form to me, and crucially, I see no reference in the text to any 60° metric pitch approximation.

MichaelG.

Nick Clarke 320/09/2021 08:12:08
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Just a small sideways point - pre-war T, as in the extract above, was a reference to the coating applied to a lens whilst post-war, due to copyright disputes, Zeiss lenses could not be referred to by their previous names. As a result T on a post-war East German lens meant it was a Tessar and S (as in the original letter posted by Michael) referred to an eastern Sonnar.

Neil Wyatt20/09/2021 14:35:48
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Posted by Michael Gilligan on 15/09/2021 18:31:52:

Posted by Neil Wyatt on 15/09/2021 18:28:12:

.

Note that T2 thread is M42 x 0.7

.

… or x 0.75 if you look a little more carefully angel

MichaelG.

🤣

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