what type of lens design does this set have

baachitraka · Nov 29, 2019

Any thing related to dagor

AgX · Nov 29, 2019

Doppel-Anastigmate is a large group of lenses.

The first division would be symmetrical and unsymmetrical
The majority of designs though were symmetrical (which makes more sense anyway with double in mind)

Second division would be cemented halves, uncemented halves and partialliay cemented halves

The most famous of the uncemented halves group is the Double-Gauss design, although the current derivatives all have cemented elements by now...

Ron (Netherlands) · Nov 29, 2019

Doppel-Annastigmat GOeRz = DAGOR ;-)

sample:

baachitraka · Nov 30, 2019

AgX · Nov 30, 2019

Ron (Netherlands) said:
Doppel-Annastigmat GOeRz = DAGOR ;-)

As I indicated the term Doppel-Anastigmat hints at a great variety of lenses. It not necessarily must be of Dagor design.
I got a listing where it is filed seperately from the Dagor, and indicating the chance that it got 8 elements instead.

baachitraka · Nov 30, 2019

Seems Series III double-anastigmats are Dagors...

AgX · Nov 30, 2019

I guess so too. (I overlooked that further designation at the opposite part of the name-plate.)

Ian Grant · Nov 30, 2019

Doppel-Anastigmat GOeRz-Ihagee is a Dialyte ands so not a Dagor - I know as I have one an f6.8 13.5cm

I also have a 1913 12cm f6.8 Dagor in a Compound shutter being later than the OP's it's actually marked as Dagor lens , these are very small lenses with excellent contrast even by today's standards, coverage is good as well so stopped down will just cover Half plate or 7x5.

Does the Compound shutter on the lens take a cable release, mine needs a pneumatic bulb release as it's not tapped for a cable release.

Ian

baachitraka · Nov 30, 2019

Ian Grant said:
Doppel-Anastigmat GOeRz-Ihagee is a Dialyte ands so not a Dagor - I know as I have one an f6.8 13.5cm

I also have a 1913 12cm f6.8 Dagor in a Compound shutter being later than the OP's it's actually marked as Dagor lens , these are very small lenses with excellent contrast even by today's standards, coverage is good as well so stopped down will just cover Half plate or 7x5.

Does the Compound shutter on the lens take a cable release, mine needs a pneumatic bulb release as it's not tapped for a cable release.

Ian

Seems it does not have a cable release.

baachitraka · Nov 30, 2019

Rear side

baachitraka · Nov 30, 2019

Should I consider this lens as Dagor or Dialyte?

Nodda Duma · Nov 30, 2019

As mentioned above, and a couple additional details from a design perspective:

The symmetry corrects coma, distortion, and lateral color. “Symmetry” in this case does not mean exactly the same lenses in front of and behind the stop, but rather the “odd” aberrations I mention above are balanced. An early evolution of the double anastigmat was to break the perfect symmetry, allowing the same correction at roughly 1 1/2 to 2 stops speed increase (f/8 ish to f/4.5)

Astigmatism is corrected by the thickness and distance from the stop.

Spherochromatism corrected by the choice of crown and flint.

Spherical aberration corrected by the shape of the lens.

The Double Gauss design is (kind of) derived from the double anastigmat, but corrects field curvature and balances higher order aberrations as well (allowing much faster f/# for same level of correction ~f/4.5 -> f/1.4) so the double gauss is considered a different and separate design family.

-Jason

Ian Grant · Nov 30, 2019

baachitraka said:
Should I consider this lens as Dagor or Dialyte?

The Series III Doppel Anastigmat is definitely a Dagor made before Goerz adopted the name, I was pointing out that not all Doppel Anastigmat Goerz lenses made are Dagor lenses. Sorry to confuse you

Mine has a very late small Compound shutter, these were replaced by the Compur introduced in 1912, so mine has to be one of the last.

You can see the pneumatic release at the bottom.

Ian

baachitraka · Nov 30, 2019

I'm going bit crazy to get to know about all good lens design from the turn of last century.

Dagors are one such design and other I came to know is Hugo Meyer's Aristostigmat.

I am looking a general purpose and high performance lens designs.

Ian Grant · Nov 30, 2019

I use a Goerz Am Opt 12" f6.8 Dagor on my 10x8 Agfa Ansco and it's a superb lens.

You have the irony that CP Goerz, Berlin, supplied lenses to the German forces in WWI and his son's both by then US citizens were supplying Goerz Am Opt (American Optical) to US forces.

The Dagor is a 6 element 2 group lens with only 4 air/glass surfaces but the important number is two internal when it comes to contrast a Tessar has 3 groups 6 air/glass surfaces, 4 internal, and a Dialyte has 4 seperate elements 8 air/glass surfaces , 6 internal. Before coatings were introduced in 1938 flare from internal air/glass reflections caused contrast loss, Iposted some examples a few years ago on this Forum, all lenses in excellent condition and the DAgor has almost the contrast of a coated/multi-coated lens, there's a noticeable drop with a Tessar, and a very significant loss of contrast with a Dialyte. As soon as you add coatings everything changes, the Kodak 203mm f7.7 Ektar a Dialyte is a superb lens with good contrast, later versions are better than the first.

Dialytes can be some of the sharpest (older) lenses around so in some respects out perform a Dagor or Tessar, however few were coated except the 203mmf7.7 Anastigmat, which with coating was renamed asan Ektar, a small number of coated Rodenstock Euynras were sold after WWII. The Dialyte design is excellent from Infinity to 1:1 Kodak sold the 203mm f7.7 Ektar for general as well as use to 1:1, here in the UK it was their lens for medical, dental, forensic and scientific work. Our British made version was #0 shutter compatible in a Kodak Epsilon, then Prontor SVS and later a Compur.

Apart from testing on my DSLR on bellows I've not used the 12cm Dagor, however I have noticed screen brightness is less than my 120mm f6.8 Angulon, despite them having the same maximum aperture.

Ian

baachitraka · Nov 30, 2019

I believe Aristostigmats should perform equal to Dagors? (Right now the plan to collect some good old uncoated lenses and plate cameras)

Shooting portraits and trees (like Wolfgang Moersch) could be the primary subjects...

Ian Grant · Dec 1, 2019

The Meyer Aristostigmats were 4 element air spaced lenses so quite low in contrast, I have a WA version.

Ian

Ron (Netherlands) · Dec 1, 2019

well...since we show here also 'our' Dagors....have only one in my collection, it's in barrel design (don't know if it would fit a compound or compur shutter) and f6,8 180mm:
(never used it)

instead I used this one a lot (guess since it came in a nice compound):

AgX · Dec 1, 2019

Ian Grant said:
The Series III Doppel Anastigmat is definitely a Dagor made before Goerz adopted the name, I was pointing out that not all Doppel Anastigmat Goerz lenses made are Dagor lenses.

In the listing I got there are Dagor III, Dagor IV and Doppel.-Anastigmat shown as different lenses and all dated at 1892.
(However that listing is from the early 50s.)

Ron (Netherlands) · Dec 1, 2019

AgX said:
In the listing I got there are Dagor III, Dagor IV and Doppel.-Anastigmat shown as different lenses and all dated at 1892.
(However that listing is from the early 50s.)

thanks, can you share the listing?

AgX · Dec 1, 2019

"Lijst van fotografische Objectieven" , J. Willink 1954

Ron (Netherlands) · Dec 1, 2019

AgX said:
"Lijst van fotografische Objectieven" , J. Willink 1954

tnx

Ian Grant · Dec 1, 2019

AgX said:
In the listing I got there are Dagor III, Dagor IV and Doppel.-Anastigmat shown as different lenses and all dated at 1892.
(However that listing is from the early 50s.)

In the late 1890's the Doppel Anastigmat Series II and IV lenses were not called Dagors, the initial Deries III were f7.7 and the Series IV f11 was the wide angle, later these were called Dagors.

Doppel Anastigmat Series I were Dialytes, you can find Doppel Anastigmat Serie 1b Celor lenses, and 1c were also Celors, then you get the cheaper Dialytes and Goerz made a few. My Doppel Anastigmat Goerz-Ihagee would have been made specifically for Ihagee.

Early Goerz Celors were un-named and just marked Double Anastigmat Series 1b or 1c and carried the Patent number.

Ian

AgX · Dec 1, 2019

Ian, it is time you publish such listing too...

Ian Grant · Dec 1, 2019

AgX said:
Ian, it is time you publish such listing too...

There;s just too much in the brain to get it all out

A unique problem with C P Goerz it there's the father's German company in Berlin and the subsidiary US company in New York run by his two sons who become independent and have been given rights to the same designs. Technically the rights to their lens designs reside with Carl Zeiss (CP Goerz, Berlin), and Schneider (Goerz Am Opt).

Then many companies pree-WWI had licences to manufacture Goerz lenses, it was the same with CArl Zeiss. So here in the UK Ross amde Goerz and Zeiss lenses like Dagors, Tessar's, Protars etc. B&L made Zeiss lenses in the US and so on. Carl Zeiss had a pre WWI binocular a nd LF lens factory, so you get Carl Zeiss, London, Tessar lenses until the factory was given to Ross during the war. Essentially rather than export lenses were made under licence.

Ian

what type of lens design does this set have

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