Graflex.org

primus96 · Posted: Mon May 08, 2006 12:51 pm Post subject:

Anyone with a Dagor tried removing either the front or rear cell and making images with the single cell remaining?
I think the great Ansell Adams made a image of a frozen waterfall with one half of a Dagor.
Can anyone tell me what their actual findings were in respect of the amount of lightloss and how far down to stop to get sharp edges?
If it's worthwhile i'll have S.K.G. engrave a dual aperture scale when re-mounting my 150mm Dagor.

Les · Joined: 09 May 2001 Posts: 2682 Location: Detroit, MI

I have a turn of the century Dagor (acually a Doppel Anastigmat series III) that I've used a a single element. I never really got the micrometers out but I think the effect is about a 1.7x magnification. I just consider each stop to be 2 stops down and go from there (ie f8 is f16) I shoot around f22 or 32 with a packard shutter and use Weston's rule of exposure "Expose the film until you think the subject is going to move" Although I believe he was doing portraits rather than architecture at the time.

primus96 · Posted: Mon May 08, 2006 3:16 pm Post subject:

My Dagor looks to have been a OEM fit on a camera in barrel mount. The aperture is adjusted by a large flange with a tiny knob to grip.
After enquiring on this forum my Dagor could be of between 1912 and 1926. I await S.K.Grimes opinion on how good a candidate it is for re-mount.
I have seen extracts from a Goerz (US) catalogue suggesting the lens is convertible.
I wondered if you introduced any severe defects when using only one half?

David A. Goldfarb · Joined: 03 Sep 2004 Posts: 142 Location: New York City

Yes, Dagors are really convertible. They are symmetrical, but it's generally considered better practice to put the stop in front of the lens than behind it, so one generally removes the front cell. I don't recall the exact conversion factor, but I think a 12" Dagor comes out about 18" or so with just the rear cell. Hunt around the forum on lfphoto.info, and you can find the exact formula.

I've tried it just for the sake of experimentation, and the result isn't as well corrected as a Dagor, but stopped down it's usable in a pinch. I have three Dagors and don't really need to use them converted, because I have other lenses, so I haven't made a regular practice of it.

primus96 · Posted: Tue May 09, 2006 12:32 pm Post subject:

Well, I dont usually have a enlargement physically bigger than 10x8 ,although if a selective enlargement it might equal a 20x16 full frame enlargement.
I don't expect perfection from a converted Dagor. If it'll give a reasonable image under the above conditions then i'll be happy. I could always use my Super Rollex roll-film back to use the centre portion of the image.

RichS · Posted: Wed May 10, 2006 6:37 am Post subject:

From what I can tell, the Dagors work as well as any of the other convertibles. I have Turner & Reichs, Gundlachs and Symmars. It all seems to depend more on the individual lens than the make or age...

I have also used cells in front of the shutter with no visible difference to using them behind. This may also depend on the lens itself> The Symmars don't like the front cell, I can say that much...

Overall, if you shoot B&W, then use a mono filter. Red, yellow, green, doesn't make much difference. My favorite is a red 23. It deffinitely make the converted lens sharper. Stopping down helps a whole lot. Many of the converts will focus shift when stopping down and that has to be checked.

If you're already having the lens mounted in shutter, than I think it's worthwhile to have the second stop range engraved. It should be a minimal cost compared to the mounting.

If you're curious, in her books, Berenice Abbott always recommended the Dagor over other lenses. Not because they were better. But because you got two "decent" lenses for the price of one

They were not considered among the best lenses 'back then'. Odd how things change over the years...

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primus96 · Posted: Wed May 10, 2006 12:12 pm Post subject:

I am sure that the great Ansell Adams used one cell of a Dagor for one of his Yosimite images.
I will have S.K.G engrave a second aperture scale based on using only one element of the Dagor.I don't know how they would calculate it.
If I am working at F32-45 and having to focus at said apertures it is going to be damn difficult.

troublemaker · Joined: 24 Nov 2003 Posts: 715 Location: So Cal

I am rusty on my Ansel history, but I think he used convertibles for a number of his images, and I may be mistaken, but I thought he usedone for his famous moonrise.
On another note, I have an image of a young Ansel using a Speed Pre-Any in the SIerra high country. And that would make some sense as they are considered to be reasonably light. From what folks say he was quite a gear head and probably tried just about anything he could get his hands on. If you ever see any photos of the gear he carried on road trips in that big old station wagon, it is an awful lot of cases and boxes and so on, lots of stuff...