Zeiss Tessar Patent

There's not really a category that covers this as Tessar lenses are used for all formats.

Did CZJ lose their rights to enforce their Tessar Patent(s) as a result of WWI, and the German defeat ?

I ask this question after a post on the LFP Forum about the date of a Tessar and someone else mistakenly saying the DRP meant it was made during the Third Reich which is quite wrong. In fact only CZJ Tessars made before the end of WWII have the DRP marking, all my later Tessars from 1919 onwards have dropped it including one I used to own from 1933.

Before WWI the Tessar design was licensed to Ross in the UK, B&L in the US, Krauss in Paris etc, who all made them usually including Zeiss in the name. However in WWI the UK Government took over the Carl Zeiss London factory in Mill Hill, putting it under control of Rossm later selling it to them, it was mainly a binocular factory but was also making Tessars, so you find Ross-Zeiss Tessars made under license in Clapham and then Ross (Mill Hill) Tessars made in the former Zeiss factory paying no royalties. You get the Zeiss name dropped from Ross WA Protars as well.

It's similar in the US where before WWI they are Bausch & Lomb-Zeiss Tessar lens and just Bausch & Lomb Tessar after., this is also when Kodak began calling their Tessar lenses Anastigmats.

This seems to be why the Tessar design is so widely copied after WWI. I've never seen anything about why Zeiss no longer controlled their Patent.

Ian

Patents only last for so many years - how long depends on the country and time. Tessars were designed in 1902 and the patent will have expired well before WWII. Germany in 1902 had two types of patent, one of which had a rather short life. DRP lasted 15 years - 1902 plus 15 lasts until 1917 which is during WWI.

Ian Grant said:

Did CZJ lose their rights to enforce their Tessar Patent(s) as a result of WWII, and the German defeat ?

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-) No german patent owner "lost his patent" due to the german capitulation and the successive reparations.
That is a common claim, but not true, nor that everyone could use a german patent. The situation was much more complex.

-) The german patent for the Tessar has ended 1922 or earlier. Likely foreign patents were not valid much longer.
Thus there is no cause for discussion at all.

Peltigera said:

Patents only last for so many years - how long depends on the country and time. Tessars were designed in 1902 and the patent will have expired well before WWII. Germany in 1902 had two types of patent, one of which had a rather short life. DRP lasted 15 years - 1902 plus 15 lasts until 1917 which is during WWI.

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Typo now corrected WWI not WWII

AgX said:

-) No german patent owner "lost his patent" due to the german capitulation and the successive reparations.
That is a common claim, but not true, nor that everyone could use a german patent. The situation was much more complex.

-) The german patent for the Tessar has ended 1922 or earlier. Likely foreign patents were not valid much longer.
Thus there is no cause for discussion at all.

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I wasn't saying that the German Patent was stripped from Zeiss, rather that Zeiss lost effective control of it in 1914 initially outside Germany - only 12 years after it was issued, they'd stopped putting DRP on their own CZJ Tessars by 1919. More importantly the British Government had given Ross the rights to continue manufacture of Zeiss designs royalty free and never returned the Mill Hill factory to Carl Zeiss. B&L also stopped paying Zeiss Royalties during WWI.

I don't know about Germany but in the UK you pay a yearly fee to keep your Patent, it maybe that Zeiss after WWIIthen felt it worthless to pay for something unenforceable, Deckel kept their 1902 Compond shutters r Patent going a little longer.

Ian

I see, you mean WWI and not WWII...

In WWI the situation was even more complex.
Zeiss to my understanding lost their british patent on the Tessar (I assume there was one, but did not check.)
But as there was no direct trade with Britain anyway and it likely would have run out short after the war (if not earlier) that rather should be of lesser importance. As long as one does not see the early postwar years as time of economical revival and thus as lost chance for Zeiss.

I got no idea why after 1919 Zeiss did not use the DRP marking.


In general, the situation was very complex, not well understood back then(!) and even now there are few experts on this historic matter.
But anyway the legal situation was, getting your right was another one.

Ian Grant said:

I don't know about Germany but in the UK you pay a yearly fee to keep your Patent, it maybe that Zeiss after WWIIthen felt it worthless to pay for something unenforceable, Deckel kept their 1902 Compond shutters r Patent going a little longer.

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Paying a yearly fee for a patent is typical for all patent authorities.
All patents run out after a given time (max. 20years).
Zeiss did not loose their german patents, but the german patent authority lay down for some time.

By the way, CZJ (Carl Zeiss Jena) is a term that to my understanding only came into existance with the nationalizing of the assets in the Soviet-zone and the founding of the people owned enterprise of that name, when already another entity had been founded in the US-zone.

Ian Grant said:

However in WWI the UK Government took over the Carl Zeiss London factory in Mill Hill, putting it under control of Rossm later selling it to them, it was mainly a binocular factory but was also making Tessars, so you find Ross-Zeiss Tessars made under license in Clapham and then Ross (Mill Hill) Tessars made in the former Zeiss factory paying no royalties.

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I assume they did pay royalties. To the British State.

In any case, attempts to get hold on german owned patents in an enemy country soon brought up the problem how to care for their firms holding a licence on such patent.

AgX said:

I see, you mean WWI and not WWII...

In WWI the situation was even more complex.
Zeiss to my understanding lost their british patent on the Tessar (I assume there was one, but did not check.)
But as there was no direct trade with Britain anyway and it likely would have run out short after the war that rather should be of lesser importance. As long as one does not see the early postwar years as time of economical revival and thus as lost chance for Zeiss.

I got no idea why after 1919 Zeiss did not use the DRP marking.

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I thought that inmediately after ww1, Ross produced the Tessar under license of Zeiss. I've read that more than once. But i can't recall if this was before ww1, or after the end of ww1.

AgX said:

By the way, CZJ (Carl Zeiss Jena) is a term that to my understanding only came into existance with the nationalizing of the assets in the Soviet-zone and the founding of the people owned enterprise of that name, when already another entity had been founded in the US-zone.

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Even early Zeiss lenses are marked Carl Zeiss Jena, that's the original name of the Zeiss company founded in 1856 and remained on the Jena made lenses a until bought by Docter Optics, aside from some post WWII lenses exported ti the US. Carl Zeiss in the West was a different company.

flavio81 said:

I thought that inmediately after ww1, Ross produced the Tessar under license of Zeiss. I've read that more than once. But i can't recall if this was before ww1, or after the end of ww1.

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Before the start of WWI Ross made Zeiss Tessars and Protars,and Goerz Dagor, lenses under license but after the outbreak of the War only made Zeiss designs. Ross were switched to their own Patented Xpres lens at their Clapham factory in 1914 an improvement on the Tessar design according to the company but imported lenses were in short supply during WWI so they continued production of the Tessar - always marked as "Ross . London . (Mill Hill) Tessar" during and after the war

Ian

AgX said:

By the way, CZJ (Carl Zeiss Jena) is a term that to my understanding only came into existance with the nationalizing of the assets in the Soviet-zone and the founding of the people owned enterprise of that name, when already another entity had been founded in the US-zone.

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You've been misinformed. See, e.g., the lens picture in http://www.largeformatphotography.info/forum/showthread.php?135839-Jena-Tessar-Oddity/page2

I expected to be corrected. The term engraved on lenses, even as a trademark, not necessarily is the company name.

But it could lead to common designations amongst users and collectors.


In the past german firms typically had their location set after their (shortened) name.
In the case of Carl Zeiss the location as part of the official name though became most important with the splitting of the company. Thus when I read CZJ, in first instance I think of the eastern entity past-1948.
But I know that some authors see that differently (as Thiele).

Even in 1931 which was the random BJP Almanac I just pulled out there's two companies Carl Zeiss Jena and Zeiss Ikon, also Schott glass, and other subsidiaries, their shareholding might not be the same even tough controlling interest would have bee with Carl Zeiss Jena the parent company, by then owned by the Carl Zeiss Foundation.

Zeiss Ikon itself was a merger of Ica (already a subsidiary of Zeiss) with Goerz, Ernemann, Contessa Nettel etc, it wasn't a takeover so one would imagine a very different shareholding to CZJ. Even in the 1939 BJP almanac the the adverts are still Carl Zeiss (London) Ltd for lenses and Zeiss Ikon Ltd for cameras with CZJ lenses, both the same address.

Ian

Zeiss stated that the Tessar patent protection ended in 1920, without going into detail what Tessar patent is referred to.

A Lens Collectors Vade Mecum starts the Zeiss section with several pages of early history. Many of the people important to Zeiss designs left the university where they had been working and joined Zeiss around the turn of the century.
"The sheer physical expansion of buildings and employees meant construction and training, and these could
not occur overnight. Zeiss always paid real interest in training, via apprenticeships but these take time. Thus
they licensed others to make the new lens designs and Zeiss Anastigmats can be found made by them today look
for Voigtlaender (Germany, to 1895), Suter ( Switzerland), Ross (UK), Fritsch v. Prokesch (Austria),
Koristka (Italy and Bausch and Lomb (USA). About half of the original anastigmats were made under license
up to 1900.


Tessar
Tessar (1902) (Layout Zei020) (P.Rudolph and E.Wandersleb, for Zeiss, Brit Pat 13,061/1902, German Pat.
142,294, USPat 721,240)
A 1902 development by Rudolph, this became about the most famous lens ever designed, and really sets a
new era. It beat most rivals on sharpness and had only 6 a/g surfaces so it was more reliable from the flare
point of view than Unar or Planar. Zeiss stated it was derived from the Anastigmat and Unar designs and this
seems reasonable from the type of development Rudolph was making by working on these by separating and
bending. (Cynics said it was a Triplet with an extra glass but this ignores several facts).
It was cheaper than Protar V11a, less prone to flare than Unar, and a very desirable item. Zeiss defended the
design and the trade name Tessar carefully, and in 1932 stated their objections to the use of their name and
"Tessar type" and "Tessar construction" in advertisements. [However it did become one of the most widely
used layouts in the industry once the patents had run out. Hence the use here of the code Q15 for the many
other users of the layout.] The Zeiss objection was fair as the trade name was theirs and experience shows
that the careful design and production of the Tessar did put it ahead of its rivals. This was shown in a
comparison of a Tessar with "other" brand Q15 lenses."

"Cynics said it was a Triplet with an extra glass but this ignores several facts."

I would not call them cynics. It is well spread among textbooks authors to describe the Tessar design as successor of the plain triplet and to call the Tessar an enhanced triplet. This makes understanding and learning easy. I know that people at Zeiss state that the Tessar instead was designed as combination of the Protar and Unar. But to understand that more lens-design knowledge is needed at the student.

AgX said:

Zeiss stated that the Tessar patent protection ended in 1920, without going into detail what Tessar patent is referred to.

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Yes, here it is fom Zeiss, p5:
https://www.zeiss.com/content/dam/Photography/new/pdf/en/cln_archiv/cln39_en_web_special_tessar.pdf