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What Schneider (Xenon) lenses could these patents show?
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PostPosted: Wed Sep 25, 2024 8:38 am    Post subject: What Schneider (Xenon) lenses could these patents show? Reply with quote
I've stumbled upon these Schneider patents from the year 1954 in France:

https://worldwide.espacenet.com/patent/search/family/007723239/publication/FR1106793A?q=FR1106793



and

https://worldwide.espacenet.com/patent/search/family/007722852/publication/FR1102390A?q=FR1102390



Does anyone know what lenses these might be for? I don't understand the French language, but I assume the text mentions that the calculations are made for a lens with 100 mm focal length and a maximum aperture of f/2, but this could very well be just standard procedure in order to make them comparable?

I haven't been able to find a corresponding German patent application yet, but there absolutely could be.

Both of these lenses are mentioned here
http://dioptrique.info/base/f/f8x.HTM
as Xenon "c" so I suppose it's likely that their final form was called Xenon. Perhaps the "c" stands for a c-mount lens? I'm not familiar though with Xenon lenses with 9-element designs like that, so it would be really interesting to know what kind of lenses these are... if they've ever been built.

Some unusual Xenon lenses I can think about (but don't really know concrete details about in terms of construction):

TV-Xenons 50, 75, 100 mm f/2
Xenon (c-mount) 25 and 50 mm f/0.95 (The 50 mm is mentioned on some sites as a 8/6 design)
Xenon (prototype?) 90 mm f/1.4
(Alpa-)Xenon 80 mm f/2
Leitz Xenon 50 mm f/1.5 (Though I'm pretty sure this is a 7/5 design and also older than 1954)

If anyone here can help me out it would be highly appreciated!


PostPosted: Wed Sep 25, 2024 1:51 pm    Post subject: Reply with quote
Retina Curtar Xenon C 5.6/35mm
Retina Longar Xenon C 4/80mm

Front halves could be exchanged, rear half (from a regular Xenon 2/50) was built into the camera.

S


PostPosted: Wed Sep 25, 2024 2:44 pm    Post subject: Reply with quote
stevemark wrote:
Retina Curtar Xenon C 5.6/35mm
Retina Longar Xenon C 4/80mm

Front halves could be exchanged, rear half (from a regular Xenon 2/50) was built into the camera.

S


Thanks! So that‘s why they have the same rear element? Interesting… didn‘t think of that possilitiy. Why would they mention f/2 though. Do you think they would actually be faster and are stopped down somewhere in the process?


PostPosted: Wed Sep 25, 2024 6:46 pm    Post subject: Reply with quote
simple.joy wrote:
stevemark wrote:
Retina Curtar Xenon C 5.6/35mm
Retina Longar Xenon C 4/80mm

Front halves could be exchanged, rear half (from a regular Xenon 2/50) was built into the camera.

S


Thanks! So that‘s why they have the same rear element? Interesting… didn‘t think of that possilitiy. Why would they mention f/2 though. Do you think they would actually be faster and are stopped down somewhere in the process?


Original f=50mm is f2! Shown here on a Reflex Retina with the 4/80mm "half lens" in the foreground. I don't own the 5.6/35mm though.

S



EDIT drawing of the original 2/50mm from the same patent:


S

EDIT II:

An early 1939 version where the attachment is placed in front of a Xenar (=Tessar type) lens can be found in US 2'169'130.

1950 patent


PostPosted: Wed Sep 25, 2024 9:05 pm    Post subject: Reply with quote
stevemark wrote:
simple.joy wrote:
stevemark wrote:
Retina Curtar Xenon C 5.6/35mm
Retina Longar Xenon C 4/80mm

Front halves could be exchanged, rear half (from a regular Xenon 2/50) was built into the camera.

S


Thanks! So that‘s why they have the same rear element? Interesting… didn‘t think of that possilitiy. Why would they mention f/2 though. Do you think they would actually be faster and are stopped down somewhere in the process?


Original f=50mm is f2! Shown here on a Reflex Retina with the 4/80mm "half lens" in the foreground. I don't own the 5.6/35mm though.

S



EDIT drawing of the original 2/50mm from the same patent:


S

EDIT II:

An early 1939 version where the attachment is placed in front of a Xenar (=Tessar type) lens can be found in US 2'169'130.

1950 patent


Many thanks - that's very helpful in understanding the somewhat unusual design. Of course they have to design around that "fixed rear half-lens". The Xenar + attachment looks even crazier. But ever since I've seen the ISCO T-Kiptagon projection lens system for 70 mm cinema projection, I feel like nothing is impossible to imagine in terms of attachment lenses. Just take a look at it... if you know the size/weight of regular cine projection lenses which are capable of projecting 70 mm film, you're starting to appreciate how crazy it gets:



https://www.in70mm.com/news/2015/t_kiptagon/index.htm

The Retina system looks way more reasonable compared to that. Have you ever adapted one of the Retine Xenons to a modern camera?


PostPosted: Wed Sep 25, 2024 10:01 pm    Post subject: Reply with quote
simple.joy wrote:

The Retina system looks way more reasonable compared to that. Have you ever adapted one of the Retine Xenons to a modern camera?


The only Retina Xenon I have is that one shown in my picture above. Since only the front part can be detached, adapting the entire xenon would be a major task Wink. No, I haven't tried one on modern digital cameras.

I do have, however, a few DKL lenses, among them

* Braun Reflex Ultralit 2.8/50mm
* Schneider Retina-Curtagon 4/28mm, Retina-Curtagon 2.8/35mm, and Retina Tele-Xenar 4/135mm
* Rodenstock Retina-Ysarex 2.8/50mm and Rotelar 4/135mm
* Voigtländer Skoparex 3.4/35mm, Septon 2/50mm and Super Dynarex 4/135mm

While the 135mm lenses are nothing to roam about, the Curtagons are quite OK (especially the 35mm which Minolta chose as a starting point for their excellent MC 1.8/35mm). The Ysarex - a pretty rare Tessar sibling - is surprisingly good, too, and the Septon is well known anyway.

S
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