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

[Counsel]

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Am 1.5.2020 um 13:51 schrieb TomB_tx:

Erwin Puts says the Leitz production records do not mention the Xenon, indicating it was manufactured by Schneider for Leitz; while the factory records show the Summarit was made by Leitz.

„..-Sadly for Tronnier, before the Xenon could be released to market Ludwig J. Bertele (who at the time had begun working at Zeiss after that brand had absorbed Ernemann) developed the Sonnar lens formula in 1931, which became publicly available as a 5cm F/1.5 lens on the Zeiss Contax I in 1932. The Sonnar was ground-breaking, and the seven elements in three groups design became a great commercial success. 

Leica, who were up and coming competitors to Zeiss’ Contax with the recently released Leica IIIa 35mm camera, needed a fast lens to compete with the Sonnar. So Ernst Leitz engaged Schneider-Kreuznach to create a fast lens. The Leitz-Xenon 5cm F/1.5 lens referencing Taylor-Hobson British patent 373950 and US patent 2019985 which was originally designed as a cinema lens came into production in 1936.  Zeiss’s Sonnar had already captured the market, and the Xenon only sold a fraction of the amount of the Sonnar…“

https://casualphotophile.com/2019/03/10/xenon-lens-history/

[willeica]

2 hours ago, Counsel said:

„..-Sadly for Tronnier, before the Xenon could be released to market Ludwig J. Bertele (who at the time had begun working at Zeiss after that brand had absorbed Ernemann) developed the Sonnar lens formula in 1931, which became publicly available as a 5cm F/1.5 lens on the Zeiss Contax I in 1932. The Sonnar was ground-breaking, and the seven elements in three groups design became a great commercial success. 

Leica, who were up and coming competitors to Zeiss’ Contax with the recently released Leica IIIa 35mm camera, needed a fast lens to compete with the Sonnar. So Ernst Leitz engaged Schneider-Kreuznach to create a fast lens. The Leitz-Xenon 5cm F/1.5 lens referencing Taylor-Hobson British patent 373950 and US patent 2019985 which was originally designed as a cinema lens came into production in 1936.  Zeiss’s Sonnar had already captured the market, and the Xenon only sold a fraction of the amount of the Sonnar…“

https://casualphotophile.com/2019/03/10/xenon-lens-history/

Great article. This shows also that Zeiss was considered to be the leader when it came to optics in the 1930s. Leitz was further down the ladder behind Schneider and others. Cameras from that era often used the 'Compur formula' to allow a choice of lenses. Leitz only served that market for a very short time as it was busy with its own focal plane shutter cameras. I have two cameras fitted with examples of the Schneider f2 Xenon lens on a Compur mount, a Nagel Pupllle and a Balda Super Baldina. I also have 2 Pupilles with Leitz Elmars. Cameras fitted with lenses with the Leitz name fetch more money these days, not because the lenses are better, but because of the allure of the Leitz/Leica name.

 

William 

[Tears Everywhere]

5 hours ago, Counsel said:

徠卡憑藉最近發布的徠卡 IIIa 35mm 相機成為蔡司康泰時的競爭對手，他們需要一個快速鏡頭來與 Sonnar 競爭。所以 Ernst Leitz 聘請 Schneider-Kreuznach 來製造一個快速鏡頭。Leitz-Xenon 5cm F/1.5 鏡頭參考 Taylor-Hobson 英國專利 373950 和美國專利2019985 ，最初設計為電影鏡頭，於 1936 年投入生產。Sonnar 的數量……”   

https://casualphotophile.com/2019/03/10/xenon-lens-history/

This link looks like a summary of Leitz-Xenon rumors.
However,  Leitz-Xenon has its own patent DE647830. And Schneider has its own experiences of super fast Gauss lens, Deutsch patent 565566, earlier than Taylor-Hobson US patent 2019985. Although the super fast Xenon was still based on another Taylor-Hobson lens. 😊

[Counsel]

The fact that Leitz had its "own" patent says nothing.  Given that Schneider/Tronnier developed the Xenon on behalf of Leitz, it is very likely that the claims in the patent were assigned to Leitz prior to filing.  This is also supported by the fact that the inventor is not named in the patent.  This is possibly based on a non-attribution request, which would be plausible because Leitz did not want to publish that no Leitz scientist had invented the lens.

Edited July 28, 2022 by Counsel
A Word was missing

[Tears Everywhere]

17 hours ago, Counsel said:

The fact that Leitz had its "own" patent says nothing.  

The Taylor-Hobson US2019985 patented at 1935, meanwhile the Leitz-Xenon DE647830 was filed at 1934. 
DE647830 filed during the review of US2019985 but did nothing to prevent patent infringement, that means Leitz-Schneider ally did not take US2019985 as a threat.

Actually Taylor-Hobson US2019985 struggled for 5 years to get patented, especially it was months later than Schneider similar design. Other Taylor-Hobson patents, i.e. US1955591, filed at 1932 and patented at 1934, only took 2 years.😊

[Counsel]

It is necessary to separate two aspects.  One thing is the development of a product – possibly including the corresponding manufacturing technology.  The other one is the acquisition of a (corresponding) patent, more precisely, the teaching, which relates to a specific product and/or individual properties of it.

The developer of a product and the patent owner or applicant can be different natural or - in the case of patents also legal - persons. 

Also important is whether a third party patent covers the product such that the unauthorized application of the teachings of the patent constitutes patent infringement.

 According to the inscription, only Taylor Hobsen's patents are relevant for the Leitz Xenon, which, however, were only valid in the British Empire (and - not quoted on the lens - in the USA) and not in Germany.  It can be assumed that Leitz or Schneider received a license for these patents, namely for their scope in the British Empire and perhaps also in the USA, i.e. for export.

 It is not possible to determine to what extent the Leitz Xenon fell under other patents without knowing exactly the structure of the product - particularly with regard to the teaching presented in the patent.

In order to be able to judge this, someone must be a patent specialist specialized for optical systems.  As far as I can see, no such person has taken part in this discussion.  

In any case, the patent literature does not provide any precise information as to whether and to what extent Tronnier was the developer of the Leitz Xenon, even if Tronnier is named as the inventor of a lens (plus many others, in total of 124).  After all, one cannot know without a thorough examination whether it is exactly the Leitz xenon or certain properties of it.

Interestingly enough, the German edition of Wikipedia states that Tronnier developed a xenon lens with a speed of 1.5 for cinematography in 1932.  In 1935 "the cinema xenon 1:1.5/50 mm was expanded to become the LEICA xenon"

The assumption is that Leitz signed the contract with Schneider/Tronnier to develop a lens with a speed of 1.5 for photo film because of the prior development of a movie lens with such a speed.  This was probably the only chance for Leitz to be able to offer such a lens in the foreseeable future, because a large part of the preparatory work had already been done by Tronnier.

Edited July 30, 2022 by Counsel

[Tears Everywhere]

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18 minutes ago, Counsel said:

In order to be able to judge this, someone must be a patent specialist specialized for optical systems.  As far as I can see, no such person has taken part in this discussion.  

Maybe I am not a specialist of optical patent, but I have do similar analysis of optical patents for years. This is the result of Leica patent DE647830. 

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[Counsel]

I recognize that you certainly have some know-how related to patents.  However, you and others do not have the ability  to examine the product to determine whether it meets the relevant features of the cited Leitz patent.  It has been to be customary to expressly indicate on a product which patents protect the product from imitations, i.e. ensure the exclusive use of the teaching of the patent.  If there is no indication and you want to know whether the patent is relevant for a product, you also have to analyze the product for the relevant characteristics.  This is not possible for a person who does not have specific know-how in the field of optical physics and access to the corresponding measuring instruments.I
Therefore, we cannot tell from the patents whether Tronnier or anyone else at Leitz (Berek?) developed the product.  You have to rely on other sources, especially the Schneider and Leitz business papers, to get this information.  It can be assumed that the authors of the relevant numerous articles had direct or indirect access to these business files.  It therefore does not seem to me justified to just speak of „rumors“ especially since there is no other information contrary to this.

Edited July 30, 2022 by Counsel
Editorial

[Tears Everywhere]

1 hour ago, Counsel said:

If you want to know whether the patent is relevant for a product, you also have to analyze the product for the relevant characteristics.  This is not possible for a person who does not have specific know-how in the field of optical physics and access to the corresponding measuring instruments.

There is one key point that Leica screw mount lenses differ from others - they are mounted on a range-finder camera.

Leica can't focus though the lens, but with a coupled range-finder. That means Leica can't work with a lens has significant spherical aberration which will cause serous focus shift at large aperture. However, the Taylor-Hobson US2019985 was a traditional lens with vary large spherical aberration, impossible to focus over f/2 by range-finder.  Only the Leica DE647830 match the requirement. But Leica DE647830 sacrifice the image flatness to did it, while Taylor-Hobson lens has almost zero distortion and very flat image field. 😊

Edited July 30, 2022 by Tears Everywhere

[Counsel]

Thank you for your valuable contribution.  I would like to end the discussion with this.  By the way, it would be more interesting for me who is behind todays fantastic development of the Apo Summicron M 2.0 50mm Asph or the excellent "Voigtländer" (Cosina) Apo Lanthar 2.0 50mm, but that's another story.

[UliWer]

Please allow me another question about the Xenon:

Has anybopdy seen a Letz catalogue or list from the times when the Xenon was produced which mentions the lens? My German catologues about the lenses for the Leica from June 1935 and Januar 1938 don‘t have it, neither does the British „General Catalogue“ from August 1936 and I don‘t know any other prewar or wartime publication from Leica which mentions the Xenon. 

Edit: I found a catalogue which refers indirectly to the Xenon: "Leica Zubehör" (Leica accessories) from Mai 1940 mentions the cap for the Xenon "Orxdochrom" and several filters which have telegram words all beginning with "Xoo..". The list also has the "Xioom" hood though no leather or bakelit container of it's own, but only a soft leather bag "Exqoo".  

Edited July 30, 2022 by UliWer

[willeica]

2 hours ago, Counsel said:

Thank you for your valuable contribution.  I would like to end the discussion with this.  By the way, it would be more interesting for me who is behind todays fantastic development of the Apo Summicron M 2.0 50mm Asph or the excellent "Voigtländer" (Cosina) Apo Lanthar 2.0 50mm, but that's another story.

We could be here all night discussing who did what, but Peter Karbe will talk on the development of the recent Leica APO lenses at the LHSA - International Leica Society- Conference which I am organising in Dublin for next October. 

I believe that the 'casualphotophile' article is as good a summary as you will get of the history of the Xenon lens and its development. I have mentioned before that I have two examples of the Xenon in its earlier Compur mount manifestation. The lens would have needed reworking for the 35mm rangefinders made by Leitz/Leica and it seems that an input of T,T&H genetics was needed to achieve this. Tears Everywhere has been promising a definitive article on this for some time and we are awaiting that. I would add that trying to tell the history of Leitz/Leica through patents is not an easy job. I have looked at these in the context of copy and fake cameras and nowhere did I find a case where Leitz defended its rights under such patents, despite obvious copies and fakes being in existence. There were various political reasons for some of this, of course

When I was in Wetzlar last month Tim Pullmann of the Ernst Leitz Museum/Archives drew my attention to the following 3 volumes by Helmut Lagler, of the German Leica Historica Society, which were on sale in the museum shop. He told me that one of the volumes identifies which Leitz staff members were responsible for each of the various patents taken out by Leitz. I did not purchase the books as they were large and heavy and also because my German is not very good.

 

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William 

[Counsel]

You can order the 8 books here

https://www.leitzianer.de/bestellen/?Bezugsquellen

[pgk]

13 hours ago, Counsel said:

It is necessary to separate two aspects.  One thing is the development of a product – possibly including the corresponding manufacturing technology.  The other one is the acquisition of a (corresponding) patent .....

And there is a third. Enforcement of the patent. Whilst it may be infringed, the cost of legally enforcing and gaining appropriate compensation will inevitably be a commercial decision. And in some cases it may be cheaper to acknowledge existing patents and pay a royalty than try to create a new patent which might be subject to legal action. The history of optical patents in the UK iindicates that little is certain when either they are garnted or enforced. Some have been succesfully enforced, others have never been tested in court.

[willeica]

On 7/30/2022 at 9:27 PM, pgk said:

And there is a third. Enforcement of the patent. Whilst it may be infringed, the cost of legally enforcing and gaining appropriate compensation will inevitably be a commercial decision. And in some cases it may be cheaper to acknowledge existing patents and pay a royalty than try to create a new patent which might be subject to legal action. The history of optical patents in the UK iindicates that little is certain when either they are garnted or enforced. Some have been succesfully enforced, others have never been tested in court.

I agree, Paul. Doing a history of optics involves a lot more than just looking at patents.

William

[Counsel]

And it needs a lot more than looking at patent litigations, as I have already stated in my previous post in detail.

[nf3996]

On 7/30/2022 at 5:07 PM, UliWer said:

Has anybopdy seen a Letz catalogue or list from the times when the Xenon was produced which mentions the lens? My German catologues about the lenses for the Leica from June 1935 and Januar 1938 don‘t have it, neither does the British „General Catalogue“ from August 1936 and I don‘t know any other prewar or wartime publication from Leica which mentions the Xenon. 

Edit: I found a catalogue which refers indirectly to the Xenon: "Leica Zubehör" (Leica accessories) from Mai 1940 mentions the cap for the Xenon "Orxdochrom" and several filters which have telegram words all beginning with "Xoo..". The list also has the "Xioom" hood though no leather or bakelit container of it's own, but only a soft leather bag "Exqoo".  

I have an English language Leitz brochure 'Handle the Leica' from August 1938. It lists the 5cm f/1.5 Xenon lens for sale at £34. The brochure also shows that the Xenon lens could be bought with a IIIb body for £59 6s 0d.

Alan

[Pyrogallol]

This is a copy of the Xenon pages from the November December 1937 issue of Leica News and Technique.

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[willeica]

8 hours ago, Counsel said:

And it needs a lot more than looking at patent litigations, as I have already stated in my previous post in detail.

Agree 100%. The history of optics shows a continuous development over time with designers taking up what has worked elsewhere and incorporating that into their own designs. This has been the practice as far back as the mid 19th Century. The impact of patents has not been as great as that of designers who have copied what has worked elsewhere and made it their own with a few tweaks. 

 

1 hour ago, nf3996 said:

I have an English language Leitz brochure 'Handle the Leica' from August 1938. It lists the 5cm f/1.5 Xenon lens for sale at £34. The brochure also shows that the Xenon lens could be bought with a IIIb body for £59 6s 0d.

Alan

Here is a 1938 UK catalogue offering the IIIb with a Xenon lens for £59 6s 0d, which has been overwritten postwar to offer a IIIc with a Summarit f1.5 5cm lens for £98 10s 0d.

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And we think that we live in inflationary times.

William 

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Hallo,

Look here: Interesting Leica gear

[JMF]

Hello,

I'd like to thank you all for contributing to such an interesting thread.

My humble contribution is adding 2 lenses to the list :

5cm  Leitz Xenon 1.5      DRP        sn 375952  3 ring    meter scale    
5cm  Leitz Xenon 1.5      DRP        sn 491264  4 ring    scale to be confirmed

Best, Jean-Marc.

 

Edited August 2, 2022 by JMF