Re: Goerz Doppel-Anastigmat Series III No. 1 Question
Quote:
Originally Posted by
KingTigerII
After Dan's comment I started looking and the lenses look similar - but I found nothing of the same design. I think you're on the money though.
Now, is this lens considered a Dagor? I read in the Lens Vade Mecum that the Dopel Anastigmat Series III were later renamed to Dagor, but I saw conflicting results on here saying that many times people just falsely claim that Goerz lenses are Dagors. This has two groups of cemented elements, but I cannot tell the layout of the individual elements.
I apologize for the questions, I'm just into researching and learning this odd ball stuff. I picked this lens up for like $50.
Hmm. Dagors and similar lenses are made up of two cells. Each cell is a cemented triplet. The cells are usually identical, i.e., the lens is symmetrical.
Yes, people do mistaken claim that Goerz lenses of other design types are Dagors. I was once sold a dialyte type as a Dagor. But Doppel Anastigmat Ser. III is the original way that Dagor was spelled.
OP, if you want to learn more about these old crocks, visit this sticky https://www.largeformatphotography.i...mainly)-lenses in the Lenses and Lens Accessories section and click on the link in the first post.
Re: Goerz Doppel-Anastigmat Series III No. 1 Question
Quote:
Originally Posted by
Dan Fromm
Hmm. Dagors and similar lenses are made up of two cells. Each cell is a cemented triplet. The cells are usually identical, i.e., the lens is symmetrical.
Yes, people do mistaken claim that Goerz lenses of other design types are Dagors. I was once sold a dialyte type as a Dagor. But Doppel Anastigmat Ser. III is the original way that Dagor was spelled.
OP, if you want to learn more about these old crocks, visit this sticky
https://www.largeformatphotography.i...mainly)-lenses in the Lenses and Lens Accessories section and click on the link in the first post.
Thank you Dan! Many thanks for the information!
Re: Goerz Doppel-Anastigmat Series III No. 1 Question
Quote:
Originally Posted by
Dan Fromm
Hmm. Dagors and similar lenses are made up of two cells. Each cell is a cemented triplet. The cells are usually identical, i.e., the lens is symmetrical.
Yes, people do mistaken claim that Goerz lenses of other design types are Dagors. I was once sold a dialyte type as a Dagor. But Doppel Anastigmat Ser. III is the original way that Dagor was spelled.
OP, if you want to learn more about these old crocks, visit this sticky
https://www.largeformatphotography.i...mainly)-lenses in the Lenses and Lens Accessories section and click on the link in the first post.
The 1895 Goerz catalog has something similar to what I have. Thank you so much!!!
Re: Goerz Doppel-Anastigmat Series III No. 1 Question
Considering the serial on your lens it is quite an early doppel anastigmat with the following Goerz aperture range: 6, 12, 24, 48, 96, 192.
The later DAGOR has not the same lens design as your lens, since it was corrected to be more light sensitive. Al the Dagors have the f-stop range starting at f 6.8. Your lens with a Goerz aperture of 6 is comparable to the f-stop equivalent of f 8 (in the early days also as f 7.7).
However the later doppel anastigmats were also corrected to be more light sensitive and got the Goerz aperture 4.6; these later anastigmats are comparable to the DAGOR.
I have a large database with GOERZ lenses and the DAGOR type anastigmats with 4.6 aperture were produced as from about serial 62xxx or just before.
Re: Goerz Doppel-Anastigmat Series III No. 1 Question
Quote:
Originally Posted by
Ron (Netherlands)
The later DAGOR has not the same lens design as your lens, since it was corrected to be more light sensitive.
They are all identical, regardless of the maximum aperture. No changes in the optical correction were involved in any f/6.8 and f/7.7 ones.
(No I don't have a database but I do have the lenses. Quite a bit of them. Stop an f/6.8 to f/7.7, and there is absolutely no difference to an f/7.7 one. Stop both at least to f/10, and they are usable....)
Quote:
Originally Posted by
Ron (Netherlands)
Al the Dagors have the f-stop range starting at f 6.8.
All the Series III Dagors longer then 300mm are f/7.7. Some of the shorter focal lengths are f/7.7, too.
Re: Goerz Doppel-Anastigmat Series III No. 1 Question
Quote:
Originally Posted by
ridax
Some of the shorter focal lengths are f/7.7, too.
Would be interested to know which ones you are pointing at!
In don't think that anyone will argue against your point that stopping down lenses will make them quite comparable!
And indeed the very long lenses as from 360mm were not f 6.8, but that has more to do with the ergonomics since they could have been made in f 6.8
It seems more a commercial kind of thing: people trying to sell their doppel anastigmats as Dagors.
Re: Goerz Doppel-Anastigmat Series III No. 1 Question
Quote:
Originally Posted by
Ron (Netherlands)
Would be interested to know which ones you are pointing at!
One example:
https://www.largeformatphotography.i...ead.php?150772
Quote:
Originally Posted by
Ron (Netherlands)
...your point that stopping down lenses will make them quite comparable! <...>It seems more a commercial kind of thing: people trying to sell their doppel anastigmats as Dagors.
They are NOT comparable. They are IDENTICAL. Again: there were no changes and there is no difference in the optical formula between the f/7.7 and the f/6.8 Dagors and pre-Darors. And people selling their Goerz Double Anastigmats as Dagors are perfectly correct.
3 Attachment(s)
Re: Goerz Doppel-Anastigmat Series III No. 1 Question
Quote:
Originally Posted by
Ron (Netherlands)
Considering the serial on your lens it is quite an early doppel anastigmat with the following Goerz aperture range: 6, 12, 24, 48, 96, 192.
The later DAGOR has not the same lens design as your lens, since it was corrected to be more light sensitive. Al the Dagors have the f-stop range starting at f 6.8. Your lens with a Goerz aperture of 6 is comparable to the f-stop equivalent of f 8 (in the early days also as f 7.7).
However the later doppel anastigmats were also corrected to be more light sensitive and got the Goerz aperture 4.6; these later anastigmats are comparable to the DAGOR.
I have a large database with GOERZ lenses and the DAGOR type anastigmats with 4.6 aperture were produced as from about serial 62xxx or just before.
Mine does go up to Goerz f/384, probably irrelevant but just to point it out.
Quote:
Originally Posted by
ridax
One example:
https://www.largeformatphotography.i...ead.php?150772
They are NOT
comparable. They are
IDENTICAL. Again:
there were no changes and there is no difference in the optical formula between the f/7.7 and the f/6.8 Dagors and pre-Darors. And people selling their Goerz Double Anastigmats as Dagors are perfectly correct.
So, I bought A Lens Collector's Vade Mecum, and this is what I found:
Attachment 230456
Attachment 230457
Attachment 230458
So as I understand it (from reading this) - it is a Dagor design, as that is related to the element layout - not the aperture. The aperture changed in the Series III later on due to a glass change, and as time progressed, the Series III was renamed the Dagor.
1 Attachment(s)
Re: Goerz Doppel-Anastigmat Series III No. 1 Question
The first portion mentions that the lens design is a GOE001 - which corresponds to this diagram in the back of the book. This design remains constant for all three descriptions.
Attachment 230466
Re: Goerz Doppel-Anastigmat Series III No. 1 Question
Indeed, but changing the glass and aperture makes it another kind of lens IMHO; therefore they are comparable but not identical.
And from a totally other point of view: you are offered a Dagor 180 mm (f-stop of course 6.8) and a Goerz Doppel Anastigmat 180mm at Goerz aperture of 6 (eq F 7.7) at the same price, which one to choose.....
However I do also concur with ridax that most people (perhaps all) do sell there dopp anastigmat correct, but that is because they're not sold as Dagors.
