Berthiot 520mm f6.3 Special Aviation

[Hightower]

Hello everyone, I am trying to seek help. Does anybody here have this lens? It is Berthiot 520mm f6.3 Special aviation lens. I bought it two weeks ago from an ebay seller, which shall stay unnamed for his own good. Lens was described as fully functional and working, but unfortunately it is completely missing rear focal group (or part). Most probably it is a tessar design, but I was not able to find that info. I am looking for anybody, who owns this lens. Thanks for your help!

[Steven Tribe]

The first thread in this section (a "sticky” ) by Dan Fromm is an excellent entry into source material about French lenses of the 20th century.

[Dan Fromm]

Steven, thanks for the plug. I'm sorry, but my Berthiot article says nothing about the 520/6.3. When I was researching and writing the article all I could find on it was that it exists and that examples occasionally come up for sale.

OP, good luck in getting the seller to make you whole.

Buying lenses made for aircraft cameras is risky. I'm not buying these days, have too much gear and there's little out there that can improve what I do or extend what I can do. But I still watch that market and see entirely too many single cells or incomplete lenses offered as complete lenses by ignorant or dishonest sellers.

[retrofocus]

Hello everyone, I am trying to seek help. Does anybody here have this lens? It is Berthiot 520mm f6.3 Special aviation lens. I bought it two weeks ago from an ebay seller, which shall stay unnamed for his own good. Lens was described as fully functional and working, but unfortunately it is completely missing rear focal group (or part). Most probably it is a tessar design, but I was not able to find that info. I am looking for anybody, who owns this lens. Thanks for your help!

I have Zeiss Fliegertruppe triplet 50cm and would also be interested to learn more about Berthiot special aviation 520mm. Can't find anything online.

[Vaidotas]

There is one listed on ebay at the moment.
Visually it looks like Berthiot Olor series IIa and max aperture supports a guess, but its just a speculation and you can make your own inspection if the lens on your hands.
As you can find on Dan’s article its a tessar variation.
Ross London made same layout Xpress aerial lens.
There are few threads related to Olor here in forum.
I found them well built and good performers.
If you in to soft lens hype, rear group can be used alone with almost the same FL.