Goertz Double-Anastigmat verses Goertz Dagor

[Greg]

Could someone please tell me the difference between a Goertz Double-Anastigmat and a Goertz Dagor? Have owned samples of both nomenclatures and honestly have not been able to tell the difference between them using B&W film.

thanks in advance

[Dan Fromm]

Well, Goerz Ser. III double anastigmats (original name) are early Dagors (later name). Same design, different name. Dagor types, six elements in two groups. Two strong and two weak reflections from each cell, and the weak reflections can be hard to see. Earliest ones f/7.7, later f/7.7 and f/6.8

Other Goerz double anastigmats are dialyte types. Celor, Dogmar, Syntor, Tenastigmat, no name but double anastigmat and all in a variety of speeds including f/6.8. All four elements in four groups, four strong and no weak reflections from each cell.

[Jim Noel]

Dagor is acronym for Double Anastigmat Goerz. I have several of both nomenclatures,both late double anastigmats and early Dagors. I see absolutely no difference them visually or the negatives they roduce.

[Mark Sawyer]

The difference I noticed when I was using Dagors quite a bit was that the early versions lost resolution near the edge of the image circle. Later versions were quite sharp all the way out. Also, the earlier Dagors had just a touch of spherical aberration, that "Dagor glow" that also caused a small focus shift when stopping down. That seems to have been corrected in later Dagors. (I wonder if the Dagor was corrected with the new glasses that were coming out? Or just tweaked in some other way?) And of course, the coated ones had a bit more contrast, although having only two inner air-glass surfaces, the uncoated Dagors were had more contrast than most uncoated lenses.

[peterkinchington]

The difference I noticed when I was using Dagors quite a bit was that the early versions lost resolution near the edge of the image circle. Later versions were quite sharp all the way out. Also, the earlier Dagors had just a touch of spherical aberration, that "Dagor glow" that also caused a small focus shift when stopping down. That seems to have been corrected in later Dagors. (I wonder if the Dagor was corrected with the new glasses that were coming out? Or just tweaked in some other way?) And of course, the coated ones had a bit more contrast, although having only two inner air-glass surfaces, the uncoated Dagors were had more contrast than most uncoated lenses.
Hi Mark,
Do you have any thoughts on the Goertz Celor 420mm f5.5?
Cheers Kanga
251330

[J. Patric Dahlen]

Hi Mark,
Do you have any thoughts on the Goertz Celor 420mm f5.5?
Cheers Kanga
251330

The Celor is a four element dialyte, sharper than and doesn't have the "glow" that the Dagor has at larger apertures. The Celor has a little lower contrast than the Dagor due to the eight glass-air surfaces compared to four, and more prone to flare if you shoot against bright lightsources. The Syntor is a slower version of the same construction. Both the Celor and Syntor were replaced in the 1910s by the Dogmar, which was Goerz's improved dialyte. I like my 6,3/135 Dogmar. Sharp lens and it's very even from corner to corner.

[neil poulsen]

Depending on how recent they are, it's possible that a Dagor could be factory coated. Goertz double-anastigmat will not be coated.

[Mark Sampson]

There is a good deal of information about Goerz lenses on the front page of this site. Dagor lenses have a long and complex manufacturing history, and those articles are of some help- there are even partial serial number lists by date.

[Greg]

Goertz double-anastigmat will not be coated.

Correct as to from the factory. I once bought a 240mm Double-Anastigmat that had a coating. Previous owner told me that it was done by the Burke & James "LENSKOTING DEPARTMENT" in the mid 1960s. At the time I remember that B&J was (sub)contracted for coating other manufacturer's optics.

[Mark Sawyer]

Hi Mark,
Do you have any thoughts on the Goertz Celor 420mm f5.5?
Cheers Kanga
251330

Pretty much what J. Patric Dahlen said. The Celor was a faster version of the Artar (both Dialytes). Like the Artar, all those internal air-glass interfaces are prone to reflections, so coatings are important. That said, I don't know if the Celor was ever made in a coated version.

BTW, when Hollywood studio photographer George Hurrell wanted a sharp alternative to his Verito, he chose the Celor.

[J. Patric Dahlen]

Pretty much what J. Patric Dahlen said. The Celor was a faster version of the Artar (both Dialytes). Like the Artar, all those internal air-glass interfaces are prone to reflections, so coatings are important. That said, I don't know if the Celor was ever made in a coated version.

BTW, when Hollywood studio photographer George Hurrell wanted a sharp alternative to his Verito, he chose the Celor.

I think the Artar and Celor were designed independently, since the Artar was designed as a process lens and the Celor as an allround lens. The Syntor would be the slower version of Celor. Both the Celor and Syntor were later replaced by the better Dogmar in the different speeds. Goerz also had cheaper dialytes like the Tenastigmat, Tenaxiar and Kalostigmat. I'm not sure what made them cheaper, but probably the glass used. I doubt that any Celor/Syntor lenses were coated at the factories, but since the American Goerz existed for much longer than the German Goerz, some Dogmars can be found coated.

Any coated German Celor/Syntor/Dogmar lenses found today would have been coated by a third party long after they were made. It's still possible to get them coated.