View Full Version : Goerz Dagor 6 1/2" f6.8 question

Nathan Appel
3-Nov-2010, 00:26
Hi, I am very new to large format and antique lenses. I picked up a kodak autographic 3A with a Dagor 6.5" f6.8 lens in a volute shutter. The shutter sounds pretty good, even at slower speeds.
My Goal: I would like to use this lens to do portraits with a home made 4x5 camera, do you think there will be ample 4x5 coverage? I have found very little information on this lens. How is it compared to the later model dagors? Thanks,

Dan Fromm
3-Nov-2010, 03:07
There are many conflicting reports about f/6.8 Dagors' coverage. Some high, others not so high. They all agree that a 6 1/2 incher will cover 4x5 with room for movements.

There are many conflicting reports about f/6.8 Dagors' image quality. Yours should be better than good enough.

Now ask it what it can do for you. You have it, no one else has that lens. None of us knows for sure how good your example is (or isn't).

3-Nov-2010, 05:41
I've become a big fan of Dagors for their coverage abililty and the image quality - I now have a 5" and a 9 1/5". I use a 5" lens on 4x5 and it covers nicely when stopped down to f16 or so (I usually stop it down to f22-f32 anyway) so you'll have no problem with the 6 1/2" covering. The 240mm, by the way, will cover 8x10. I find the coverage tends to agree with Goerz's published figures, which can be found in their catalogs on the Camera Eccentric (http://www.cameraeccentric.com)site. Don't forget that you can use them converted - one cell yields approximately 1.8x the focal length at a similar multiplier to the aperture.


Lynn Jones
3-Nov-2010, 12:52
All of the American made Dagors (you can tell because they are in inches) covered 65 degrees at f22 focused at infinity.


3-Nov-2010, 15:20
I have an early Schneider 165mm Dagor 6.8 and it covers 5x7 with at least a little movements. Unless the Goerz is drastically differently it should probably cover 4x5 well.

Jim Galli
3-Nov-2010, 19:20
It'll work fine and have all the coverage you'll ever want on 4X5. For portraits, try it with just the back element. Dagor's had too poor a correction to be considered serious convertibles but sometimes for portraits, imperfect correction isn't such a bad thing. It should focus around 11 3/4 inches or so with the single anastigmat at the back. Yes, that's why Goerz called it a 'doppel anastigmat'.

Larry Whatley
4-Nov-2010, 21:31
Here's some bench data on a 6 1/2 in. dagor, Nathan; the dagor is my favorite old lens, btw. The old ones are quite variable, but this example is typical: more than 100 lines/mm of resolution wide open, center field, down to 50 lpmm 2" off axis, and 25 lpmm at 4". (4" corresponds to 32 deg. half field angle for this fl.)

The visual focus wide open tends to be a little shorter than stopped down, so you may want to focus wide open, then move the rear standard back about .7mm before stopping down and taking. At f/22 resolution is about diffraction limited: 85mm on axis, down to about 70 for most of the field out to 2 1/2 " then rolling off to 30 at 4". This focal length dagor vignettes about 30% at f/16 at 4".

Another 6 1/2" example I have tests out sharper than this, showing the more typical sharpening up near the edge of the field (65 lpmm at 3 1/2") before falling off rapidly. Old tessars do this too.

Good luck with your homemade camera; this lens will give you nice coverage with movements.

- Larry Whatley

16-Nov-2010, 08:09
I have a 6 1/2 inch Dagor on a half plate (4 3/4 x 6 1/2) camera. I would worry a little using it wide open, but since I always stop down to at least f/22 there are no problems. You should be fine at 4x5.