Supplementing my comments above on Staeble and the Memmingen works utilizing their products; some time ago I was tempted to try another Fraunhofer doublet, so now I have the Leitz monster sitting on top of a tripod waiting for the weather to suit me.
p.
Further to the point above ad presuming Alpa quality control of the lenses they put their name on. I have som personal experience of this:
A long time before the Vallorbe plant closed, I had beeen on a job in Geneva and used the excellent Swiss train sevice to go there. I was curious as to how they went about testing their merchandise .
Mr Bourgeois showed me around (He was particularly proud of the roman road tracks outside and would like to sell me a 360degree rotating camera, while all needed was to have one of my Alpas looked after). The factory had a basement room with a pillar at one end for fastening lenses to be tested , and a large, colourful and detailed target at the far wall. (I did snap a few pictures of the factory and the test room with my Minox but no repro here. I have not seen them for years, also 8x11mm is not easily digitized)
He said that all lenses they received were tested there before the special Alpa/omega filter mount and front ring was attatched and some were rejected. The rejection policy is confirmed in the Thewes book where he states that Rolleis proposed contribution (ZIV designed lenses) did not make it. The two prototype(?) Rollei/Alpas (135 and 35mm) I have are optically sufficient but Pignons might not have liked their mechanics. Much later when they were on the brink of bankruptcy they started selling lenses labelled (made for Alpa) presumably not vetted in Switzerland (apart from the small batch of Kern Switars mounted in a japanese helix which I presume was mounted with permission and advice from Aarau.)
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I keep supplementing this thread:
In this case not beacuse of the lack of response or to expand public knowledge, but to correct one of my less precise remarks ebove.
I wrote that I had aquired another Fraunhofer doublet; while strictly speaking, the original Fraunhofer achromat with a convex crown glass in front of a concave flint glass had a small air gap.
My Staeble and Leitz varieties are cementet, no air gap, so calling them Fraunhofer to distigusih them from the Steinheil variety of achromat is not entirely historically exact but should do to identify which shape and glass is in front.
p.
It's great to know that you're so familiar with stuff like that... because I've only started doing some research around 1.5 years ago, I'm lacking a lot of knowledge on a variety of topics when it comes to lenses, lens design, the optical industry and its history etc. so I'm always happy to learn about that - thanks for sharing your thoughts!
I've once read about a 'Steinheil Triplet' as a lens description from another manufacturer - do you know if that's a thing (patent)?
it is years since my brief stint of physics studies, and optics was not regarded as important then, so my lack of deeper knowledge is monumental.
However, my computer aids in gathering info- a good source for early lenses is the french site dikoptrique where one of Steinheils early efforts on doublets are listed as: dioptrique.info/OBJECTIFS2/00063/00063.HTM.
Further listings af triplets before 1914 yields nothing from Steinheil, and this list of triplets after 1914 maily gives the names in the patent descriptions, not the factory, so you have to know where for example mr. Glatzel worked: dioptrique.info/base/f/f3-1914.HTM.
You may also try "perplexity.ai" as search engine its LLM will give you a view of the majority of web myths. As all "artificial imbecility" machines it is completely devoid of critical faculties, but very polished in its presentation of fake "facts" and irrelevant circumlocution. It does,however turn up good leads in the form of a short list of publkished mails while implicitly contradicting itself in subsequent sentences if pressed.
Thank you! Very interesting info in those sites. đđ
Unfortunately those links did not work. But after some more clicks I found a 1881 patent of a triplet by Steinheil dioptrique.info/OBJECTIFS1/00026/00026.HTM
The lens construction is same kind as in the later Culminar 85mm: a triplet with cemented front lens, a little like a reversed Tessar. The front lens in this portrait lens is thinner than in Culminar but the same idea.
Many other patents there. This the main page: dioptrique.info/sommaire/sommaire.HTM
Edit. Here's Culminar design news.mapcamera.com/maptimes/oldlensnuma_culminar-85mm/
Wow - thanks! What a fantastic site! Quite a lot of work assembling that. Will have to take a closer look what it covers, but it seems very impressive. I'm trying to incorporate some information about lens designs into my upcoming articles as well. I found sliders to be an interesting tool in order to compare different lens designs. It's nowhere near scientific (like Bill Claff's offerings for example), but fun to get an impression how similar/different the lenses in question really are.
I'd love to try a Culminar 85 mm f/2.8 by the way, even though that design can't be called a Triplet in my opinion... it has 4 elements after all. Some lenses were called "Dreigliedrig" (three-membered) in German patents, where they're talking about three groups, not elements. Stumbled upon that curiosity while looking up Agfa stuff.
My old German book call it "Triplet mit verkitteter Vorderlinse". Like it calls Tessar/Xenar "Triplet mit verkitteter Hinterlinse".
We have some problems with translations between different languages. I think that what is called Lens in English is an Objektive ( The whole lens with all it's elements). What is called an element in English is a lens in my mind. And what they call a group in English is an element in my thinking. That's a problem.
For your curiosity here's a " Triplet mit verkitteter Vorder- und Hinterlinse" , Cemented front and rear elements, called also Heliar type: dioptrique.info/OBJECTIFS1/00024/00024.HTM
This one has five lenses in my mind but only three ones in English. In English maybe five elements in three groups. But it's still a Triplet!
This slider does not work in my browser. Could you, please, post two single pictures to compare?
Sorry - I didn't clarify... That's just a screenshot of the slider. Of course it doesn't work. It's just meant as an example how it will be portrayed in the final (Tomioka) article I'm working on. You'll find a couple of those (however none with lens diagrams, as far as I remember) in the existing articles, like here for example:
deltalenses.com/the-makers-noritsu/
You're right. The common English use is more consistent when it comes to the use of lens/element so I think it should be used for the most part. Calling a Heliar a Triplet doesn't feel right. Lens/element = Linse/Element in German and group = Gruppe also does work, even though translations from the past have to be looked at carfully because of the circumstances you've mentioned. As someone from Austria I've never used "Linse" for "Objektiv" in the first place - that doesn't seem to be common around here.
I think there are more reasons for using the common version in English than the other way around, even though a lot of important historical developments originated in Germany.
Thank you for the clarification! I tried to slide the slider couple of times and nothing happened! So I thought there's a problem with my browser, I could not imagine it was a fake slider.đ
No, but what is called for Objektiv in German is a Lens in English. A "Linse" is an element in English.
Btw. A "Triplet" discussion with diagrams of a four element triplet and a five element triplet. www.dpreview.com/forums/post/67405553
Sirs,
To further extend this longish thread,
I noted a comment above that the Noflexars were good for UV. The measurements and positive conclusions I have seen apply to the two-glass varieties, not the T-noflexar with its rear field-flattening element.
To contine ad Novoflex, I recently aquired their 35mm variety.
Its snap-out focussing-extension-mechanism is certainly convenient (especially compared to extension rings), and except for choosing reproduction ratio accuracy (moving in stages, not a continuous process), it is a lttle bit faster than twiddling the very long helix of my Leitz close-up lens. BUT of course the short focal length is a disadvantage.
p.
yet another follow up: the post ad Noritsu a few steps up from here is abolutely well worth reading for adaptation enthusiasts and experimenters. Too bad that the time of finding such machines in skips is long past.
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