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View Full Version : Goerz Dagor 7inch / 180mm IC ?



taulen
15-Jan-2011, 13:50
Hello,

I just bought a Goerz Doppel-Anastigmat 7inch / 180mm
This ebay-sale : 290518625451
Do anyone have any info regarding image circle on this lens ? Would appreciate it. If only an approximate guess =)

Do any of you think it will be able to fit it to a shutter, or will I have to use a packard or something alike ? =)

Thank you.

Steven Tribe
15-Jan-2011, 15:10
Cameraeccentric can help you out with image circle in terms of plate size covered - but there are differences of opinion as how wide you can go beyound the offical figures.
As far as shutter go, you will probably have to go to the dial set compur or compound.

Steven Tribe
15-Jan-2011, 15:25
I have looked. This was probably mounted on the Goerz Ango focal plane camera which sold at lot around 1900. This would have been the 13x18cm version of the Ango - which matches coverage from another source I have which says 13x18 at f6.8 and 21x27cm stopped down a little. In spite of the focussing mount on the one you have, the lens cells are identical to the usual barrel mount.

Dan Fromm
15-Jan-2011, 16:51
Steven, Taulen, Dagors' coverage is somewhat controversial. If you ask the site's search function to find a thread titled "Lousy Dagor" it will direct you to a long discussion of 7" Dagors' coverage. The thread was initiated by an eBay seller, long since disappeared, who complained bitterly that his 7"/6.8 Dagor wouldn't cover 8x10. It came out that he'd sold 7"/6.8 Dagors with the claim that they covered 8x10. Parts of the discussion are quite funny, but it is long.

More seriously, Goerz isn't the only company that made Dagors. Boyer sold a very close copy named Beryl and, mounted for copy cameras, Emeraude. Same prescription, different mountings. SOM Berthiot sold an f/6.8 Dagor clone as the Serie VIb Perigraphe.

Boyer claimed that Beryls cover 85 degrees. However, my friend Eric Beltrando, with whom I wrote the so-far definitive Boyer company history and account of their products, has a ray-tracing program that he uses to evaluate lenses. And he has Beryl and Dagor prescriptions. Read about all that on www.dioptrique.info . He has told me more than once that Beryls are good for 70 degrees for general use, 55 degrees for demanding work. He got much the same results with Dagor prescriptions from Goerz patents.

Berthiot claims 65 degrees for the Serie VIa Perigraphe. I have a 135 that I haven't been able to ask about coverage, but I find Berthiot's modest claim much more convincing than Boyer's.

Believe what you will, but I think it is best to take all coverage claims with a large grain of salt. If you want to know whether a lens will do what you need as well as you want, ask it. And remember that since contact printing demands much less image quality in the negative than enlarging, a lens that gives apparently poor image quality in the corners when the neg is examined closely may be better than good enough for contacting.

Cheers,

Dan