Crown Graphic w/315mm-f12 lens configuration.

Crown Graphic w/315mm-f12 lens configuration.

Crown Graphic w/315mm-f12 lens configuration.

The last on the Crown Graphic:-)
I had this urge to get a long lens for my 4×5 wooden field view camera. Well; boys need their toys. So for a while I looked at a Nikkor-M 300-f9 nice, popular and pricey. Well; my toys are only reasonably priced 🙂 :-).
And then I came across a Symmar convertible 180/315mm on a sale for much, much less than ½ the price of the Nikkor, I could not give that-up, so I purchase it without thinking much about it.
This is not an horror story; when the lens came, it was perfect and Schneider do make good stuff. However, some thinking on how to use it was due, since neither the field 4×5 or the CG. had the bellow extension needed for a proper use of a 315mm focal length.
Other challenges had to be considered too:
1. Even with the front element removed the lens was heavy for a wooden frame, sagging and wobbling are not good attributes after all.
The CG. provided the rigidity and most of the movements that I could possibly do with a long photo lens
2. With the front element removed the shutter is exposed, with my thumbs dexterity it was imperative to find a good solution. I decided to find a UV-Haze filter that would fit the inside threat of the Synchro-Compur shutter, that turned out to be not possible . I had to settle for a filter that fits snug in the cavity glued with a drop of Locktite. I do have other lens for the 150mm range.
3. Unable to change the bellow length, the only alternative was to extend the lens board.
Of course if I had a machine shop it would be easier, but I had to do with what I could make in my basement hand held wood working tools. I finished with a design of a square extended tube 75 mm long made with 6mm thick plywood fixed at one end to an existing CG. lens board; the other end it holds the rear element and the shutter assembly. It is rigid, and light; well suited to the CG frame. The max extention from the neg. plane to the shutter plane is 400 mm (15-3/4in)
4. I missed a proper focusing scale on the CG, so I made a suitable one glued to the rail
I tested the affair on my last trip, not that many shots but…. I am happy with it, pictures with this camera to follow 🙂

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