View Full Version : How can I tell if its a dagor?

John Kasaian
8-Mar-2004, 21:24
I just got a 10-3/4" labelled Gennart f/6.8 which I am comparing side by side to a Goerz 12" Dagor f/6.8. The reflections(one bright, one dim) are identical. Unscrewing the elements, the elements of both lenses exhibit the same convex/concave - concave/convex relationship leading me to suspect that the Gennart is also a double anastigmat "dagor" design. So far, I haven't found anything on the web about Gennart lenses, but there is some info on Gennart cameras. Can anyone out there tell me if Gennart in fact marketed a double anastigmat "dagor" lens and if possible, what company produced them for Gennart? Both the 12" dagor and the 10-3/4" appear to be in the same size(externally) compound shutter although the 10-3/4" lens is a slightly smaller piece of glass.


Jim Galli
8-Mar-2004, 21:45
I play this game too John. My Trigor has identical reflections as my Dagors as does my WA Wray process and my Kenro K & K2. A Dagor group should have 2 bright reflections for the 2 air glass surfaces and 2 ghosts for the 2 cemented surfaces. Right? If it looks like a duck and quacks like a duck it's probably your wife watching an Aflac commercial. Put it on the 11X14 and stop it down to f45. If it covers it's a Dagor type.

9-Mar-2004, 16:42
JIm---your Kenro Special K was made by Am Opt, it is a Dagor, in fact I had an 8" coated Kenro K that was serial numbered right alongside a gold-dot Dagor, (832xxx, as I remember) and had nearly identical back focus, reflections, and the image was even better---those Kenro Dagors were tweaked for copy lenses, having a somewhat flatter field (less S.A). I let it go for <$100, but then we all make blunders......

John if you want a definitive answer send it to me and I'll use it for awhile and compare it to my Am Opt Dagor.... ;-)

11-Mar-2004, 09:38
Gents -

If it ain't a Goerz, it ain't a "Dagor" - period.

tim atherton
11-Mar-2004, 09:43
"If it ain't a Goerz, it ain't a "Dagor" - period."

Really - so what about the Carl Zeiss Dagors or the Kern Swiss Dagors? Both have which have led to some of the best Dagors ever made... (the 180 f9 CZ Dagor for example)

Jim Galli
11-Mar-2004, 10:41
The Trigor, K, and K2 are made by CP Goerz American Optical Company, and while they don't say "DAGOR" any where on them, I'm far more interested in the images they are able to paint on my film MattO. In fact I'll admit that I get some extra pleasure when I pay $45 bucks for something that other folks are paying $450 for because it has to say "Dagor"

Dan Fromm
11-Mar-2004, 13:25
Not long ago the notorious Dagor77 educated me a little about what exactly a Dagor is. He cribbed from Kingslake.

As he explained it, a real Dagor's element's surfaces are: ( )(( from the outside in, a reverse Dagor's (Kinglake's parlance, I believe) are (( )(. To add to the fun, the Voigtlaender Collinear and Steinheil Orthostigmat are ( ))(.

There's more that one way, it seems, to make a symmetrical anastigmat. And they're not all Dagors.

To add to the fun, I have a mystery Boyer, around 200 mm, max aperture f/7.7 that seems to be a symmetrical anastigmat. It is engraved "<< S >> 1/1" with no model designation. The focal length isn't marked either. Any suggestions what it is or how to discern the curvature of the cemented surfaces?



Dan Fromm
11-Mar-2004, 16:28
Sorry, folks, meant "double anastigmat," typed "symmetrical anastigmat."