Any idea about the maker of this Petzval?

[cyberjunkie]

I've found 5 or 6 old petzvals where the inner tube was reversed and the focus knob replaced with it that way.

The more i think about it the more i am confused!
If i reverse the barrel the thread for the lens shade would go inside the bellows!
The cells have different diameter, whatever i do, the side with the thread for the shade is where the cell with the air-spaced glasses will go. It is simply not possible to screw the achromat cell to the same side of the shade.
Again, the only answer that comes to my mind is that somebody fitted the elements to the wrong cell. Unfortunately, i am the first to find it quite unlikely, as the cell mounts are different, one is longer and with smaller diameter. I don't think that the two elements would go to the mount where the achromat is presently fitted. When i disassembled the two cells, i found no evidence of any problem: no play, rings of the exact size and depth, etc.
If a distancer ring is of the right depth to secure the achromat with no play, how could i use the same distancer for the two elements, which are deeper?

The more i think about a solution, the more i am left in the dark. That's the only certainty i have


have fun

CJ

[cyberjunkie]

Voigtländer changed to other system for rear pairs about 1880.
Voigtlaender is a common replacement for Voigtländer in written German and the s in Braunschweig is the alternative "f"!
Just Braunschweig means after 1888.

You already corrected yourself.
"Wien und Braunschweig" means between 1852 and 1862, if i correctly recall the dates.

Finding answers to my questions about this lens is proving to be a very difficult task.
I think i will reopen the lens soon and re-check everything.
Now i'm not even sure that the glass at the back is a cemented doublet. When i inspected the components, i took it for granted, the shape and thickness were right, but now i remember that i couldn't see the seam between the two elements. I thought i was seeing three reflections, but now i am not so sure...

I checked the Vademecum for a Voigtlander lens which has an air spaced doublet at the front (Dallmeyer style, with both curves pointing outwards, and with a brass ring that separates the two glasses), and with a meniscus at the back (also curved outwards). There is not such a lens.
I just contacted an italian gentleman who wrote a very nice book about 1800 french lenses, and who's writing another book about some brands of german lenses of the same period.
I hope to get some informations that would guide me to the right direction.
I'll take some better pictures to help him find the "diagnosis".
If there is somebody interested, i will upload the pics to a Flickr set, and post the link here.

It's a pity that the title of this thread is so misleading. There is no reference to the word "Voigtlander", hence those interested in early Voigtlander lenses have a very slim chance to find my post.
If a moderator is reading: is it possible to rename the thread?
I don't think it's so big a mistery, or that the lens is one-of-a-kind, but it's different from all the picture (live or from catalogs) i have found online, that's for sure.
So it could be of some interest for Voigtlander enthusiasts out there.

P.S.
Steven, i sent you a PM and found that your mailbox is full. I guess you have to delete a few old messages to make some room for the new ones.


cheers

CJ

[cyberjunkie]

After more than eight and a half years, blocked by the covid in Italy, went back to the place where I had stored this lens (and plenty of unfinished projects), and took it home with me.
I showed the lens to a competent repairman who happens to be a friend, and to the most knowledgeable photographica vendor active in my area. It seems I was right, it can't be assembled in any other way, and there are practically zero chances that somebody messed with the glass elements in the past. Even reversing the focusing gear is impossible, cause the attachment for the shade would go at the back! Reversing the inner tube is also very unlikely, for the same reason.
On top of that, it was INCREDIBLY HARD to disassemble the lens, which suggests that for many many decades the objective was left untouched. There is also no trace of the use of tools on the heads of the screws, and all the threads look pristine.
The fact that the glass elements are signed and the barrel is not could be due to the fact that the barrel was not actually made by Voigtlander. Maybe a magic lantern maker asked Voigtlander for the optical elements and had the brass work done by somebody else.
The reversed Petzval design is probably not as odd as it might seem. The use on a magic lantern implies conjugates radically different from a "normal" photographic use. I had already given a thought about that, and one of the two gentlemen stressed that, albeit quite uncommon, the solution makes a lot of sense.
The other one tried the objective on the ground glass and reported that the image looks beautiful, with no apparent flaws.
If anybody is interested, I am willing to take a few more pictures of the lens. The original pics I posted are frankly outrageous Phones had terrible cameras back at the time...
On the historical side, which is what I find most interesting at the moment, to correctly date the lens I must find out in which exact period the two factories (Vienna and Braunschweig) coexisted. I found conflicting info online. If somebody out there owns the great book by H. Thiele, well... that's were all the correct historical info can be found!

[Steven Tribe]

Here is the latest take on Vienna/Braunschweig addition/final move from D’Agostini.

You might want to remove the footnote ads before the Mods discover them!