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Leitz Xenon 5cm f/1.5 Brief Guide - Rumors and Facts


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After review historical documents and a record of 200 samples, I am trying to solve those rumors about Leitz Xenon.❤️

 

Brief Conclusion:

1. The total of Taylor-Hobson (TTH) engraved Xenon would be close to 2000 lenses.

2. Xenon was designed and made under the Leica patent issued in 1937, with the collaboration of Schneider.

3. However, that patent was a modification based on the US and British patent of TTH.
It needs TTH's license if selling Xenon in those countries. (So did the early Summarit.)

4. All TTH-Xenon were in feet scale, in order to sell in US and British.

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There are rumors about Xenon was designed by Horace William Lee, the inventor of patent US2019985.
But the "DRPa" engraved on Xenon, which means "German patent pending", leads us to another clue.

Patent DE647830 was a 7 elements Gauss type f/1.5 lens, filed by Ernst Leitz GmbH in Sep 1934, pending and then issued in 1937. 
It did not describe an inventor in patent document, but highly possible designed by Albrecht Wilhelm Tronnier of Schneider.

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Edited by Tears Everywhere
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6 hours ago, Tears Everywhere said:

There are rumors about Xenon was designed by Horace William Lee, the inventor of patent US2019985.
But the "DRPa" engraved on Xenon, which means "German patent pending", leads us to another clue.

Patent DE647830 was a 7 elements Gauss type f/1.5 lens, filed by Ernst Leitz GmbH in Sep 1934, pending and then issued in 1937. 
It did not describe an inventor in patent document, but highly possible designed by Albrecht Wilhelm Tronnier of Schneider.

 

 

They aren't simply rumors : US patent 2019985 and British Patent 373950 (reported, as you say in the "TTH" Xenons and Summarits) were indeed originated from a design of H.W. Lee on behalf of Kapella, a British Design firm which granted the rights to Taylor, Taylor-Hobson ; worth noting, the description in the British application form quotes an aperture of f 1,4 ! but a focal lenght of 1"... probably specs achievable for a cine lens. (and one can easily find Xenons 25mm 1,5 for C-mount, indeed, and even f 1,4 - in recent years they made even a Cine lens 25mm f 0,95...always Xenon-branded  😎)

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And considering the years (1930 for the Lee application - 1934 for Leitz) i think that for having the right to sell Xenons 5cm in US and Britainthey had to reach an agreement with TTH about the recognition of the originailty of the Kapella-TTH design.  It would be worth to investigate the Schneider-TTH and Schneider-Leitz agreements... "Xenon" was a brand name undoubtly invented by Schneider for MF/LF lenses which were their main market... it's quite reasonable, as you say, that the actual design (also for the 5cm version), was indeed by Schneider: I would be curios to know if the Schneider-Leitz agreement did grant only to Leitz the right to make and sell a Xenon for 35mm cameras... maybe it was for 1,5 aperture only... other 35mm cameras with 50mm Xenon lens do exist (Retina for example, Exakta too, and maybe others) but don't know if with 1,5 aperture (Retina Xenon is 1,9).

Interesting enough,  A.W. Tronnier, the designer of Schneider you quote, worked for Voigtlander after WWII... and probably designed the Nokton 50 1,5... 😎

 

Edited by luigi bertolotti
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2 hours ago, luigi bertolotti said:

They aren't simply rumors : US patent 2019985 and British Patent 373950 (reported, as you say in the "TTH" Xenons and Summarits) were indeed originated from a design of H.W. Lee on behalf of Kapella, a British Design firm which granted the rights to Taylor, Taylor-Hobson ; worth noting, the description in the British application form quotes an aperture of f 1,4 ! but a focal lenght of 1"... probably specs achievable for a cine lens.

An optical patent will choose a focal length as example, usually 1" in British patent or 100mm in German Patent, but that patent do not limit to that focal length only.
Such as Leica patents of Xenon (DE647830) and Hektor (DE585456), they all have 100mm in patent document, but actual products are 5cm/1.5 and 7.3cm/1.9 respectively. 

I have read some physic journal papers,  filed by H.W. Lee during 1924 to 1935, Lee always described himself came from "Research Department, Taylor, Taylor and Hobson". All those optical designs in science papers were marked as "Tayor-Hobson (H.W.Lee)". It is clearly that Lee worked for TTH over decades and designed those lenses under TTH. 😊

Xenon, as you said, is only a commercial trade name. The name "Xenon" can be tracked back to late 1920s in Schneider's list, years before Leica announced Xenon 5cm. There were lots lenses named Xenon in different designs. Leica only owned the patent of 7 element Gauss type, others were still owned by Schneider. But that is another story. 😊 

Edited by Tears Everywhere
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Very complex story... I've found these other references, which go back to previous years.. they refer also to "TTH (actually Kapella Limited that days)" : looks that there was really a sort of personal competition between Lee and Tronnier... 😉  https://www.reduser.net/forum/showthread.php?154412-Who-is-the-father-of-all-fast-50mm-lenses-Planar-vs-Opic-Lens-evolution

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38 minutes ago, luigi bertolotti said:

Very complex story... I've found these other references, which go back to previous years.. they refer also to "TTH (actually Kapella Limited that days)" : looks that there was really a sort of personal competition between Lee and Tronnier... 😉  https://www.reduser.net/forum/showthread.php?154412-Who-is-the-father-of-all-fast-50mm-lenses-Planar-vs-Opic-Lens-evolution

Thanks Luigi

That is a great link. The story of lens development is a continuous one as a read of Kingslake's book or the Lens Vademecum indicates and the whole progress through Aplanatic ( I have several from the 1850s), Rapid Rectilinear and Double Gauss and into the designs of the 20th century is a fascinating one. The main improvements seemed to have involved putting together different groupings of lenses and then testing them. The development of new glass types was also significant.

There is a complex series of patents surrounding the Xenon. Generally patents in those days applied only in the country where the patent was issued. Leica itself was never very assiduous in following up on breaches of its own patents, but it did not want to breach patents in lucrative target markets or, indeed, in its own home market. As far back as the 1850s several people eg Grubb and Dallmeyer, were working at the same time on the same broad lens design types with occasional disputes over copyrights and patents. This seems to have also been the case in the 1920s and 1930s with Lee, Tronnier , Merte and possibly others involved around the same time in the design of a fast standard lens. I need to dig further into my own material here, but it is difficult to determine who was actually the 'Father of the Xenon' . A paternity dispute would be difficult to determine.There is, however, a high degree of logic in regard to the actions of Leitz/Leica.

I will look into my resources and revert if I can find anything additional on this most interesting topic. Paul (pgk) has also done a lot of research in the area of lens design and I will also get in touch with him.

Finally, thanks to Tears Everywhere for raising this most interesting topic.

William

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Having consulted German patent documents several years ago while researching some of the high-speed lens designs created by Ludwig Bertele, it came as a surprise to see that part of the Reichsadler eagle logo had been blacked out in the patent illustration for the Xenon lens shown by Tears Everywhere in posting #2.

I was the editor of a technical publication for some 15 years prior to retirement, and the publishing house had a strict rule that no photograph or document appearing on our pages should be subjected to any form of retouching or alteration. So the 'edited' Reichsadler came as a surprise.

German law has requirements that our forum must conform to in such matters, but while it may be desirable to prevent the misuse in the present day of some logos and other symbology from the past, does the law make no exception for material reproduced as part of a historical study?  According to my wife, who was formerly a historian, material from the past that is being cited in one's writing should be presented without changes.

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17 minutes ago, roydonian said:

Having consulted German patent documents several years ago while researching some of the high-speed lens designs created by Ludwig Bertele, it came as a surprise to see that part of the Reichsadler eagle logo had been blacked out in the patent illustration for the Xenon lens shown by Tears Everywhere in posting #2.

I was the editor of a technical publication for some 15 years prior to retirement, and the publishing house had a strict rule that no photograph or document appearing on our pages should be subjected to any form of retouching or alteration. So the 'edited' Reichsadler came as a surprise.

German law has requirements that our forum must conform to in such matters, but while it may be desirable to prevent the misuse in the present day of some logos and other symbology from the past, does the law make no exception for material reproduced as part of a historical study?  According to my wife, who was formerly a historian, material from the past that is being cited in one's writing should be presented without changes.

As an optical history researcher, I do try to provide the original materials without modify.
Unfortunately, the Nazi mark was blocked by European Patent Office, not me or forum manager. 😅
Here is the link of original document:
https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=DE&NR=647830    

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vor 44 Minuten schrieb roydonian:

...

Would the image of a swastika improve anything on the optical calculation of the lens?
The sensible laws prohibiting the publication of National Socialist symbols date from the time of Allied military government.
Since shameful propaganda is still being carried out with these party badges from the worst past, it should also be acceptable for historians to live with these blackouts for several generations.
Their imagination should be sufficient to imagine the suffering behind it.

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29 minutes ago, mnutzer said:

Would the image of a swastika improve anything on the optical calculation of the lens?
The sensible laws prohibiting the publication of National Socialist symbols date from the time of Allied military government.
Since shameful propaganda is still being carried out with these party badges from the worst past, it should also be acceptable for historians to live with these blackouts for several generations.
Their imagination should be sufficient to imagine the suffering behind it.

For what's worth: the so called "worst past" is back, and is in power today, even if with a different name...

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Going back to actual topic here, I started by looking at the lens Vademecum and to say that the situation is complicated is an understatement. I will do my best to summarise it and to give as many answers as I can. A man called C.S. Weaver interviewed Dumur about this lens and he indicated that Leitz realised after they had taken out their patent that Schneider had an overlapping design and in order to maintain good relations Leitz adopted the Schneider name Xenon and presumably there was some kind of commercial consideration. Dumur made no reference to the fact that the lenses contained a TTH reference and patent number.

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Moving on to Schneider, the company made a range of lenses, many for movie use, which carried the name Xenon. The Leitz Xenon design is said to have been close in layout to the Schneider Xenon 25mm f1.3 and Leitz said there was independent development and an agreement to share. There is a lot more here too.

Finally, the Lens Vademecum would appear to accept that the OPIC design of Lee for TTH proved to be the parent of all the 'modern' fast Gauss lenses. It is acknowledged, though, that fast Gauss lenses were devised by Merte as the Biotar f1.4 for Zeiss and by Tronnier as the Xenon for Schneider, but it is stated that TTH are usually said to have had some form of Master Patent for a time. This may explain why a Leitz lens with a Schneider name had to acknowledge TTH for certain markets. There is an awful lot more to this as will be seen by my poor quick screen grabs, but I think that the bits that I have extracted fit with what we know happened.

A complex situation, therefore. There was a lot of this type of co-operation in the German industry at that time. This did not often affect the Leitz products branded as Leica, or intended for Leica cameras,  but other Leitz lenses were almost identical to lenses which carried the names Zeiss and Welta and others and were in almost identical Compur mounts. There is one example seen where such a lens branded as Leitz was put on a German made Kodak camera. But, I'm going off topic, apart from the point that there was more cooperation than most people realise among the German manufacturers and the staff moved around the industry a lot in those times.

I'll leave it at that.

William

 

 

 

 

Edited by willeica
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7 hours ago, willeica said:

Finally, the Lens Vademecum would appear to accept that the OPIC design of Lee for TTH proved to be the parent of all the 'modern' fast Gauss lenses. It is acknowledged, though, that fast Gauss lenses were devised by Merte as the Biotar f1.4 for Zeiss and by Tronnier as the Xenon for Schneider, but it is stated that TTH are usually said to have had some form of Master Patent for a time. This may explain why a Leitz lens with a Schneider name had to acknowledge TTH for certain markets. There is an awful lot more to this as will be seen by my poor quick screen grabs, but I think that the bits that I have extracted fit with what we know happened.

In my research years, I have saw those competitors of world's first fast Gauss lens. But forum rules do not allow talk too mach about non-Leica equipment. Here is a brief history:

1920 TTH Opic, f/2.0, 6E4G, 50º
1927 Zeiss Biotar, f/1.4, 6E4G, 35º
1927 TTH Ultra, f/1.4, 8E4G, 50º
1930 Schn Xenon, f/1.2, 8E5G, 25º
1930 TTH Super, f/1.3, 7E5G, 40º

As you can see, TTH is the pioneer of new construction, universal purpose Gauss lens. Zeiss Biotar is a cinematography lens with narrow image filed and the design based on TTH. So does the Schneider version Xenon. But TTH and Schneider all have the patent of 5-group lens before Leica, that's why Leitz Xenon have to engraved all of them on lens.😊

 

 

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22 minutes ago, Tears Everywhere said:

In my research years, I have saw those competitors of world's first fast Gauss lens. But forum rules do not allow talk too mach about non-Leica equipment. Here is a brief history:

1920 TTH Opic, f/2.0, 6E4G, 50º
1927 Zeiss Biotar, f/1.4, 6E4G, 35º
1927 TTH Ultra, f/1.4, 8E4G, 50º
1930 Schn Xenon, f/1.2, 8E5G, 25º
1930 TTH Super, f/1.3, 7E5G, 40º

As you can see, TTH is the pioneer of new construction, universal purpose Gauss lens. Zeiss Biotar is a cinematography lens with narrow image filed and the design based on TTH. So does the Schneider version Xenon. But TTH and Schneider all have the patent of 5-group lens before Leica, that's why Leitz Xenon have to engraved all of them on lens.😊

 

 

Don’t worry about strict forum rules here. The non Leitz/Leica items here are extremely important in indicating the origins of a lens that was sold by Leica for use on its cameras. As I indicated above, there was a lot of cross fertilisation of ideas and people within the industry at that time and Leitz itself made lenses for use by other manufacturers on non Leica cameras. Cooperation between Leitz and other manufacturers was not unknown and  some of it was a bit like the L Mount Alliance 80 or 90 years before its time. 

Your list and your reasoning above fit with what it is said in the Lens Vademecum, which contains massive amounts of information on lens development. It is my bible on early lenses, particularly developments in the 19th and early 20th centuries. I will now look at Kingslake’s book, which is more discursive, to see if it has anything to add. 
 

Barnack and Berek did not develop their cameras and lenses in a vacuum and they would have been aware of what was going on around them, particularly in Germany which had a very successful photographic equipment industry involving many different players.

William

Edited by willeica
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Interestingly, Cooke Optics, who are the 'descendants' of TTH, don't mention the Xenon in their history timeline: https://www.cookeoptics.com/t/history.html. It might be worth contacting them because they do have an interest in their history, and I think that they have retained old records for research and use. In a similar way to Leica the firm also notes a 'Cooke Look' and tries to explain its existence: https://www.cookeoptics.com/t/look.html. I must admit that a Leitz Xenon is one of the lenses which appeals to me - I do have an early TTH Cooke Triplet from the 1890s.

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Thanks Paul. I am glad you are on here. The Lee master design for TTH is the OPIC. There are a lot more TTH designs and models mentioned in the Lens Vademecum, too numerous to list here. I’m looking at Kingslake this morning. His is considered to be one of the standard reference works on lens development.

William

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Kingslake's is a good book but he did not have access to things like the online RPS Journal which means that some of his dating of earlier lenses and consequent assumptions are incorrect. His design info is great though (one of my friends attended his 90th I believe) and as a Kodak chief lens designer his mid-20th century info is as detailed and precise as you might expect.

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Kingslake gives the same chronological sequence, Lee, Tronnier and Merte. He mentions the Schneider Xenon, but not the Leitz version. He does mention the Summar, though and the Summitar.

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The diagrams on the next page do not show the Leitz Xenon and I can post them if anyone is interested. There is a reference to the Noctilux and the fact that it had the usual six elements with the two outer surfaces being aspheric. My take away from all of this is that lens development was progressive over time with designers borrowing from each other. Leitz/Leica did not exist in a vacuum and Berek and Barnack borrowed from the best in the business. This may seem to be heretical here, but all of the historical facts point that way. My view has always been that their greatest achievement together was the collapsible 50mm Elmar and its ancestors. Without that lens we would not have Leica or the Leica Forum today.

William

 

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31 minutes ago, willeica said:

The diagrams on the next page do not show the Leitz Xenon and I can post them if anyone is interested. There is a reference to the Noctilux and the fact that it had the usual six elements with the two outer surfaces being aspheric. My take away from all of this is that lens development was progressive over time with designers borrowing from each other. Leitz/Leica did not exist in a vacuum and Berek and Barnack borrowed from the best in the business. This may seem to be heretical here, but all of the historical facts point that way. 

Kingslake's is a good book, without much details.
Even the aspheric surface is still another innovation of TTH.😊
In 1934, Lee designed an usual 6E4G Gauss lens, achieved f/1.1 with one outer aspheric surface.
30 years later Leica cited that f/1.1 patent, added one more aspheric glass, then the first Noctilux was born.

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Back to our topic, who is the designer of Leitz Xenon?
If it is an 
independent development of Leica,  the answer should be Max Berek or Otto Zimmermann. I don't think they are.

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