[rcheshire (Rowland)]

Looking around, this question has been asked before, one way or another. And, I'm not sure why the documented setup doesn't work for me. Takahashi specs cite 56mm back focus. Now back focus appears to be as indicated in the diagram. However, another source suggests BF is measured from the back of the flattener. I'll measure it all up and see what gives.

Edit: 'Metal back focus' is the distance from the union of the flattener and camera adapter to the photographic plane.