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

[willeica]

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Thanks. Another take on the Xenon is here. 

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

The author states

"Tronnier was given the impossible challenge of developing a fast lens to compete with the Ernostar. He used some design elements from the Opic lens invented in 1920 by H.W. Lee of Taylor-Hobson in the United Kingdom. The Opic moderately collapsed the symmetrical structure of the Zeiss Planar from 1896, and reduced spherical, chromatic and field curvature aberration in the symmetrical Gaussian design. Tronnier adopted the asymmetrical design of the Opic, but to be able to achieve his goal he needed to create a six element lens. However, to achieve the desired speed the front elements had to curve, which increased the refractive index and introduced large aberrations from each element". 

In relation to the Leitz Xenon the author states

"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. "

I believe that Leica was more than 'up and coming' by the time the IIIa with 1/1000th sec top speed was introduced, but an arrangement with Schneider was admitted to by Dumur. What the exact nature of that arrangement was is unclear. Parts of Tronnier's design did owe something to Lee's design for TTH and this seems to have resulted in the carry through of the TTH patent to the Leitz Xenon. I am not a big fan of talking about lenses in terms of designers like Berek, Mandler, Karbe etc. A lot of such talk is barstool stuff. Anyone who knows anything about Leitz/Leica knows that it was and is very much a 'team company'. For example, there are plenty of documents which show the lens department foreman Zuhlcke continuing to test the 50mm Elmar and sending the results to Barnack long after Berek had designed the lens. It is clear, though, that throughout the lens making industry, at that time, designers kept themselves informed about what others were doing and this 'market intelligence' led to the developments which have given us the marvellous lenses which we have today.

William 

 

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[luigi bertolotti]

1 hour ago, Tears Everywhere said:

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.

 

Thanks ! You made me discover the huge infos on patents that can be found on the Net... 😃 I found quickly Marx and Seidel patent for the Noctilux (quoted as a 52mm f 1,2 lens...) where they quote the above Lee patent. for the aspherical lens.: I wonder if TTH actually tried to MANUFACTURE the "Lee's aspherical" .. even if in math terms is a rather "simple" aspherical I suppose that in the '30s it was almost impossible to make it at industrially acceptable costs. 

As a side note... while searching, I also got to know that Mandler patented a mirror lens...

 

Edited May 2, 2020 by luigi bertolotti

[willeica]

Thanks Tears Everywhere from me too. You made me revisit  a lot of material that I knew I had, but had not looked at for some time. You (and Luigi) have also drawn my attention to some new material which I had not seen before. This is how the forum works best, when we share material and ideas, just like the lens designers in times past.

William

[Tears Everywhere]

14 hours ago, willeica said:

Thanks. Another take on the Xenon is here. 

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

The author states

"Tronnier was given the impossible challenge of developing a fast lens to compete with the Ernostar. He used some design elements from the Opic lens invented in 1920 by H.W. Lee of Taylor-Hobson in the United Kingdom. The Opic moderately collapsed the symmetrical structure of the Zeiss Planar from 1896, and reduced spherical, chromatic and field curvature aberration in the symmetrical Gaussian design. Tronnier adopted the asymmetrical design of the Opic, but to be able to achieve his goal he needed to create a six element lens. However, to achieve the desired speed the front elements had to curve, which increased the refractive index and introduced large aberrations from each element". 

The followings might be very controversial...

In my research, there is no license or agreement between TTH and Schneider, only piracy. The first Xenon started from the 1925 design, German patent DE439556. However, if you look deeply into DE439556 , you will find out a 3-element "Single Gauss Lens". The usual Gauss lens we know is a 6-element Double Gauss design, contains 2 single gauss part. You need two DE439556 lens, put them face to face, then you get a 6-element 70mm f/2 lens which identical to TTH Opic design.

In order to pirate TTH Opic design, Schneider filed a sham optical patent in 1925. Then Schneider even sold their piracy German Opic back to British, competed with the genuine Opic.

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Edited May 3, 2020 by Tears Everywhere

[Hello]

Thanks for this informative info. In your original post, you allude to their being close to 2,000 of the TTH lenses made. The wiki on the Xenon lens indicates 2,000 made in 1936 and 1,500 made in 1937. Which is correct?

Also, are there any examples of ones with nice optics? The TTH's I've come across are generally in horrible shape when it comes to the glass.

[Tears Everywhere]

1 hour ago, Hello said:

Thanks for this informative info. In your original post, you allude to their being close to 2,000 of the TTH lenses made. The wiki on the Xenon lens indicates 2,000 made in 1936 and 1,500 made in 1937. Which is correct?

As you can see in the table attached in original post, not every Xenon made in 1936 and 1937 was engraved with TTH patent.

The total production of Xenon during 1936 to 1937 were 3500 units, as the Leica Wiki described. But only 2000 of them engraved with TTH marking, the other 1500 units were normal Xenon.😊

 

[pgk]

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4 hours ago, Tears Everywhere said:

The followings might be very controversial...

In my research, there is no license or agreement between TTH and Schneider, only piracy. The first Xenon started from the 1925 design, German patent DE439556. However, if you look deeply into DE439556 , you will find out a 3-element "Single Gauss Lens".

Interesting. The photographic lens world may well have a history of 'sharp' practice. In 1857 Thomas Grubb patented his Aplanatic lens (a doublet). In 1866 Dallmeyer patented the Rapid Rectilinear - said, even in Kingslake's book to have perhaps been suggested by two Grubb Aplanatic doublets placed symmetrically around a central stop. However I have a Grubb built lens of exactly this type (engraved Grubb Doublet and consisting of two Aplanatic lenses placed symmetrically around a central Waterhouse stop) which I am certain preceded's Dallmeyer's patent date wise. It is also known the Dallmeyer was using Grubb lenses prior to 1866 on stereo cameras. So who should the real credit go to for the Rapid Rectilinear?

[luigi bertolotti]

30 minutes ago, pgk said:

Interesting. The photographic lens world may well have a history of 'sharp' practice....

By sure, and it has been like this also in other sectors in the growing industries and cross-border markets (car engines, for example) ... but, coming back to the original topic of Leitz/Schneider Xenons... there is a detail that probably is rather impossible to scrutinize... was also MONEY involved in the agreements ? I mean, the quoting of the TTH patents on Xenons is an assessed fact...but what did it mean, in real terms ? Simply a writng (clearly agreed between Schneder/Leitz and TTH) to recognize an intellectaual right ? Or , by logic, Leitz agreed also to PAY to TTH some money  on any lens sold in US/Britain ?  After all, we aren't speaking of artistic items... but of products to be industrially made and sold... companies like TTH and Schneider and Leitz were surely concerned to have their inventions widely recognized... but at the end, not for the glory of, but to be able to cash in from them.. 

Edited May 3, 2020 by luigi bertolotti

[Pyrogallol]

All this reading makes me want one. GAS.

[pgk]

1 hour ago, luigi bertolotti said:

 ... but, coming back to the original topic of Leitz/Schneider Xenons... there is a detail that probably is rather impossible to scrutinize... was also MONEY involved in the agreements ? I mean, the quoting of the TTH patents on Xenons is an assessed fact...but what did it mean, in real terms ?

Its very difficult to appreciate the marketing decisions made at the time too. Was there perhaps even a perception that an inscription of what may then have been a famous firm such as TTH may have helped sales? Or was English lens design seen as having excellence. Or was it actually that a legal challenge might have been considered damaging to reputations? Things are rarely as simple as they seem from a future perspective.

[Tears Everywhere]

2 hours ago, pgk said:

Interesting. The photographic lens world may well have a history of 'sharp' practice. In 1857 Thomas Grubb patented his Aplanatic lens (a doublet). In 1866 Dallmeyer patented the Rapid Rectilinear - said, even in Kingslake's book to have perhaps been suggested by two Grubb Aplanatic doublets placed symmetrically around a central stop. However I have a Grubb built lens of exactly this type (engraved Grubb Doublet and consisting of two Aplanatic lenses placed symmetrically around a central Waterhouse stop) which I am certain preceded's Dallmeyer's patent date wise. It is also known the Dallmeyer was using Grubb lenses prior to 1866 on stereo cameras. So who should the real credit go to for the Rapid Rectilinear?

 I have the patent document of 1866 Dallmeyer Rapid Rectilinear. 😊

Although there were prior arts about "two Aplanatic doublet" lens, but those were fully symmetrical. The innovation of Dallmeyer is let the rear doublet has smaller size than the front doublet, making it asymmetrical in diameter.  

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[Tears Everywhere]

1 hour ago, luigi bertolotti said:

By sure, and it has been like this also in other sectors in the growing industries and cross-border markets (car engines, for example) ... but, coming back to the original topic of Leitz/Schneider Xenons... there is a detail that probably is rather impossible to scrutinize... was also MONEY involved in the agreements ? I mean, the quoting of the TTH patents on Xenons is an assessed fact...but what did it mean, in real terms ? Simply a writng (clearly agreed between Schneder/Leitz and TTH) to recognize an intellectaual right ? Or , by logic, Leitz agreed also to PAY to TTH some money  on any lens sold in US/Britain ?  After all, we aren't speaking of artistic items... but of products to be industrially made and sold... companies like TTH and Schneider and Leitz were surely concerned to have their inventions widely recognized... but at the end, not for the glory of, but to be able to cash in from them.. 

I have a time line of the full story about TTH, Schneider & Leitz Xenon, based on my personal research...

TTH asked quite high license fee, the US street price of Leitz Xenon was 50% higher than Zeiss Sonnar f/1.5 for Contax at those years.

 

Edited May 3, 2020 by Tears Everywhere

[pgk]

17 minutes ago, Tears Everywhere said:

 Although there were prior arts about "two Aplanatic doublet" lens, but those were fully symmetrical. The innovation of Dallmeyer is let the rear doublet has smaller size than the front doublet, making it asymmetrical in diameter.  

Quote from Kingslake's History: "The front and rear component's were similar but not identical [as per the patent, BUT ..... ] ..... Very soon Dallmeyer found that it was better to make the two halves identical, and this arrangement became the well-known Rapid Rectilinear [RR]". The patent was the innovative bit, the RR lens almost certainly already existed. I should add for the sake of clarity, that William and I have been researching Grubb lenses and that we have located only 5 of Thomas Grubb's Patent Doublet lenses (two Aplanatics around a central stop) which are known to still exist. I have one of these. His son, Sir Howard Grubb, also produced some Patent Doublets which were sold later on in the 1880s which suggests that the design competed well against the RR then too - which probably isn't surprising. I will add that Kingslake would probably not have come across the Grubb Patent Doublet in the days prior to the internet and when Grubb lenses did not command particularly high prices. Some of these and other old photographic lenses are in museums, most locked away in secure storage and very rarely displayed.

Whilst Leica lenses are a fascinating subject of study, the information available on them is substantial and accessible, not so for many other manufacturers.

Edited May 3, 2020 by pgk
typo +

[pgk]

For the sake of completeness, and to illustrate the vagaries of patents, here is an excerpt from Thomas Grubb's 1857 patent which clearly shows that he was aware of the potential to use his Aplanatic lens 'in combination with another of similar construction to itself'. He was very close to describing the RR and this might explain Dallmeyer's clearly defined patent of dis-similar sized lenses. Patents were not (and are not) as simple as we might hope. The Leitz/TTH Xenon may illustrate this rather well too!

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[willeica]

Where do I begin? All of this seems to have kicked up several degrees while I was otherwise occupied this morning.

3 hours ago, Tears Everywhere said:

The total production of Xenon during 1936 to 1937 were 3500 units, as the Leica Wiki described. But only 2000 of them engraved with TTH marking, the other 1500 units were normal Xenon.😊

 

Hartmut Thiele shows ranges for up to 6,505 Xenon serial numbers as having been assigned, but the Blue Book only shows 6190 as having been manufactured between 1936 and 1950. Thiele's list needs to be read carefully as Leitz often did not use the full number ranges assigned.  Perhaps, we should leave the final word to Dumur (who should have known the facts) when he said that about 2,000 lenses were made. Going back to Thiele, he does end each entry line for the Xenon with 'Schneider-Pat.' which one must assume came from the record books in Wetzlar. Interestingly, the first Summarits have entries which end with 'Xenon-Variante'.

5 hours ago, Hello said:

Also, are there any examples of ones with nice optics? The TTH's I've come across are generally in horrible shape when it comes to the glass.

Early lenses had softer glass than today's offerings and were easily scratched, particularly by photographers trying to clean them with their ties. It is the same with early coated lenses. Haze and fungus are also quite common and the more glass and elements that were used in construction, the more likely that these would exist. You really need to examine such lenses personally before purchase. That being said, I have 12 Summars (a specialist subject of mine) and they were mainly bought at auction or online and almost all of them have glass elements that are in good condition.

The discussion about Grubb and Dallmeyer is not totally irrelevant as it shows that the same issues existed in the 1850s and 1860s about who 'invented' developments in lens design. Thomas Grubb entered into heated discussions about lens design in the pages of the Photographic Journal with another scientist/optician who styled himself as a 'Wrangler from Cambridge'. A 'Wrangler' was, apparently, someone who was good at maths. This got quite heated on occasion with the Wrangler making disparaging comments about the 'Emerald Isle' as Grubb was Irish. He may have been someone who was beating a drum for another manufacturer such as Ross or Dallmeyer or who was trying to get a foot on the lens design ladder himself. I mainly collect the simple Aplanatic designs of Thomas Grubb from the 1850s and 1860s, but I have one later (possibly 1880s) which carries the name of Grubb's son Sir Howard Grubb. It is described as an Aplanatic Doublet and it has a Waterhouse stop between the two sets of elements. The bottom set is stuck, so I cannot remove it to make precise measurements, but both sets appear to be the same size. Paul (pgk) and I have between us about 10% of the Grubb lenses still known to exist. Can you imagine owning 200 Xenons?

9 hours ago, Tears Everywhere said:

In my research, there is no license or agreement between TTH and Schneider, only piracy. The first Xenon started from the 1925 design, German patent DE439556. However, if you look deeply into DE439556 , you will find out a 3-element "Single Gauss Lens". The usual Gauss lens we know is a 6-element Double Gauss design, contains 2 single gauss part. You need two DE439556 lens, put them face to face, then you get a 6-element 70mm f/2 lens which identical to TTH Opic design.

In order to pirate TTH Opic design, Schneider filed a sham optical patent in 1925. Then Schneider even sold their piracy German Opic back to British, competed with the genuine Opic.

These are strong words. I have no way to contradict this, but Leitz , to their credit, seem to have got some message through Schneider as otherwise the TTH would not have appeared on their Xenon lenses. The 'Schneider -Pat.' referenced above is also interesting. Leitz were always very cautious in their approach even though there is no evidence that Leitz ever sued anyone for the many breaches of their patents. I looked into this recently while preparing an article on Leica Fakes and Copies. Tears Everywhere, do you intend to publish your research anywhere, as you certainly seem to have a wealth of fascinating material?

Finally the lens development journey through time from Grubb through Dallmeyer, Ross, TTH, Kodak, Zeiss, Schneider and Leitz and many, many others is one of continuous development and borrowing of ideas. Does anyone have a single example of where somebody or some company successfully sued for breach of lens design copyright or patent?

William

[pgk]

39 minutes ago, willeica said:

Does anyone have a single example of where somebody or some company successfully sued for breach of lens design copyright or patent?

No, but I am aware that the optical design world is quite a small one and designers tend to know one another or of one another's work and conferences are held. I was talking to a friend who is an optical designer only yesterday. He use to work in Oberkochen (😉) but now works in the UK. We have a mutual friend who worked in Midland as head of optical design and whom I went to college with .....

In small worlds there has to be a lot of respect for each other's work or secrecy impairs progress. Perhaps it is also this that drove appreciation of patents?

[Tears Everywhere]

1 hour ago, willeica said:

Perhaps, we should leave the final word to Dumur (who should have known the facts) when he said that about 2,000 lenses were made.

Paul (pgk) and I have between us about 10% of the Grubb lenses still known to exist. Can you imagine owning 200 Xenons?

I concluded the total TTH-Xenon will be about 2000 units, not only based on Dumur's speech...

Actually, I count it by myself. 
The record of 200 Xenon posted in the beginning of this topic, each number was recorded by myself. I can tell you where each sample came from.😎

As you can see, from serial number 288001 to 2887xx, there were about 790 Xenon, almost all of them were engraved with TTH U.S.Pat. First batch of TTH-Xenon is close to 800 units.
From serial number 2887xx to 290000, there were 1200 Xenon manufactured but only 50% of them engraved with TTH. The second batch of TTH-Xenon is close to 600 units.
So did the third batch from serial number 375501 to 377000, about 600 TTH-Xenon manufactured. All 3 batches of TTH-Xenon would be about 2000 lenses. 😊

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[Pyrogallol]

I see 288753 for sale now

https://www.ebay.co.uk/itm/Taylor-Hobson-Leitz-XENON-f-5cm-1-1-5-LEICA-L39-Rangefinder-Lens-Made-in-1936/362857542449?hash=item547bfeb331:g:zbgAAOSwsAdd~UQD

 

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Hallo,

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[luigi bertolotti]

4 hours ago, Tears Everywhere said:

I have a time line of the full story about TTH, Schneider & Leitz Xenon, based on my personal research...

TTH asked quite high license fee, the US street price of Leitz Xenon was 50% higher than Zeiss Sonnar f/1.5 for Contax at those years.

 

that's interesting... Leitz had not to pay TTH for lenses sold in Germany, it seems (and other European countries , too) ...  have you a similar figure for German prices ? I'd be curios to check if the price gap you quote was similar in Germany too...

Edited May 3, 2020 by luigi bertolotti

[zeitz]

William's query "Does anyone have a single example of where somebody or some company successfully sued for breach of lens design copyright or patent?" is an interesting one.

I have examined a case in the US concerning the optically compensation zoom lens.  Dr Frank Back, owner of Zoomar Inc, Glen Cove, NY, held the US patents 2,454,686 (Nov 1948) and 2,718,817 (Sept 1955) for "variable focal lens systems for motion picture and television cameras."    Zoomar sued Paillard in 1957 over the design of the Pan-Cinor 70 and Pan-Cinor 100 lenses.  Zoomar lost in both the US District Court and the US Court of Appeals.  The court ruled that the patents are invalid "for want of invention, insufficient disclosure, and excessively broad claims".  You would think that the first practical zoom lens would have had sufficient invention.  Dr Back invented not only the first optically compensating zoom lens for movie and television cameras, but he also designed the first zoom lens for 35mm cameras (Voigtlander Bessamatic 36-82mm f2.8 lens) and the first zoom lens for medium format cameras (170-320mm f4.0 lens).   (Of additional interest is that the 170-320mm f4.0 is the only production lens that I know of for Visoflex II/III.)