How to properly install Dagor in Copal shutter

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!

I would worry more about not touching aperture and shutter mechanics than optimization of total distance.

I believe the distance will influence the curvature of sharpness. Test what is important for you, landscape or macro.

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Originally Posted by Oslolens

I believe the distance will influence the curvature of sharpness. Test what is important for you, landscape or macro.

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That is interesting to know, thanks. I will experiment while keeping the lens cells safely away from aperture and shutter.