How to properly install Dagor in shutter

blee1996

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Hi, I recently acquired a Goerz Berlin Dagor 180mm f/6.8 in cells only, and would like to know what is the best way to install it properly in shutter. The Dagor cells already come with thread adapter/bushing for Compur/Copal #1 shutter.

When I first got the cells, I tried it on a borrowed Linhof branded Compur shutter. I screwed the elements (with bushing) all the way in without forcing it, and the total length of the lens is about 39.1mm (front thread of front cells to thread of back cells). I took some photos and they look all right, but I did not take any photos of flat brick wall.

Today I got a black Copal #1 shutter, which I intend to be the final home for the Dagor cells. However, I can screw in both the front cells and back cells into the shutter a lot deeper than the Compur. And right now it is about 36mm from front to back, and I can further reduce it by screwing in further. Unlike modern lens cells, the Dagors cells with adapter/bushing does not seem to have a "stop" position.

From what I read, Dagor are totally symmetrical thus front and back cells should be equal distance from the diaphragm/aperture. Is it correct? And anybody knows the proper/optimal distance for Dagor 180/6.8?

And what will be my best approach to properly seat the cells, i.e. how far should I screw in the front the back cells. And how can I measure the distance between front//back cells and diaphragm/aperture?

Thank you!
 

lobitar

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I fear your Dagor cell bushings are intended for the prewar type of rim-set Compur shutters, that didn't have the cutout of the outer part of the threads, something most rim-set shutters got at some point of time after the war. I believe your best bet would be to use one of these older shutters, if you don't want to have new bushings made.
 

Ian Grant

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Early Berlin Dagors were also in B&L Unicum shutters, but usually the aren't marked Dagor, just Doppel Anastigmat. I'd look for a Dial Set Compur but you need to be aware there are variations , see here.

Either way you need to find someone with a 180mm Berlin Dagor and get then to measure the shutters tube length but I think it's the fairly common early Compur #1. I have one in a Unicum shutter I'll try and check it later.

Ian
 

Ian Grant

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No cells for Dial-set shutters are not interchangeable with Rim-set shutters.

When Deckel switched to the rim-set Compur shutters they wanted to rationalise the tube sizes, as there had been too many variations, which was costly. So to prevent mix ups with dial-set cells designed for different tube lengths and width the changed the thread pitch of the rim-set Compurs, Gauthier who were also shareholders in Deckel, changed their thread pitch as well. At that point Zeiss were the controlling shareholder of both companies anyway.

Ian
 

reddesert

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This is the kind of question that is certainly difficult to answer without pictures of the lens cells.

The problem with somebody measuring another 180mm Dagor total length from front thread to back is that if theirs doesn't have the same lens mounting cells (the metal parts), the measurement could be different. You would at best need to measure from front glass surface to rear glass surface.
 

Ian Grant

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The only variation of the Compur #1 dial-set shutter was the #1a which has a 35mm internal diameter size tube. instead of 30mm. It appears that CP Goerz Berlin marked the new barrels/cells for the Compound shutters as Dagor. B&L had a trading partnership with Zeiss (as did Ross in the UK) manufactitng some of their lenses under license. When Deckel introduced the more reliable Compound shutters, Unicum sales to Europe plummetedm and B&L began making Compounds under license in the US, later becoming a partner in Deckel.

Measuring the front glass to rear glass surfaces forgets that newer optical glasses mean the Dagor is evolving. Having 4 small Goerz Berlom lenses it's very easy to notice a very signifcant difference with the Unicum celled 18cm Dagor and Compur/Compound Goerz lenses, I have a 12cm in a Compoud #0

Ian
 
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blee1996

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Thank you all for sharing your knowledge. I just did some measurements and took some photos.

The detailed description on front lens group

C.P, Goerz Berlin 295489 Dopp-Anaastigmat Series III Dagor F=180mm 1:6.8
So according to serial number db, it should be manufactured before and near 1915.




The front cells and back cells look to be identical, both in terms of diameter and depth.



With the thread adapter/bushing, the measurements are as following. The bushings are of different outer diameter and depth.



So based on the above information and images, would anyone kindly suggest the right dial/rim-set Compur that will match the cells?

Thank you!
 

lobitar

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The thread diameter of the cells from my Xenar 4,5/150mm that's mounted in a rimset Compur from the late fifties (?) is 40,0 mm (front) and 35,85 mm (rear). But there is a problem with your cells not having a flange to stop against the outer face of the shutter. The front cell might be all right to turn all the way to the bottom, but that wouldn't be feasible for the rear cell. This is because the rear inner bottom of the shutter is rotating with the aperture ring, which means you wouldnt be able to adjust the aperture if the rear cell is turned all the way to the bottom. There might very likely be another version of the shutter with another arrangement in the rear. There is or has been a Swede here in the forum (possibly called JPD?), that seems to know a lot about old shutters, perhaps you could ask him?
 

Romanko

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You could try contacting S.K. Grimes (https://skgrimes.com/shutters/). If they can't help you they probably know someone who can. There is also an option of adapting a larger shutter for your Dagor by machining simple mechanical adapters.
I have two Dagors but they are 105 and 125 mm focal lengths. They are mounted in dial-set Compur shutters. The cells have different design. The thread is smaller diameter than the rest of the housing. Do you know what camera your lens came from?
Do you need to know the exact spacing between the cells? Can it be determined experimentally?
 
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blee1996

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Romanko said:
Can you use the ground glass for adjusting the spacing? What camera are you using?
Click to expand...

I'm using a Linhof Tech V. Even with 8x loupe, it is not that easy to judge small differences in sharpness on the ground glass. I was indoors today due to the rain, and will try again outdoors tomorrow. Hopefully sunnier and brighter.
 

Kino

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Can you shoot photographic paper for the tests?
 

Romanko

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What are the thread sizes on the front and rear cells (not the adapters)? Chances are you just need to find a proper shutter without going into the trouble and expence of adapting the cells to a different shutter. Unfortunately, they were not standardised and different manufacturers used different thread sizes (both metric and imperial).


 
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