Fotoman Camera sells a complete range of Helical Focus Mounts, available to accept either #0 or #1 shutter sizes. A 65mm is available with proper DOF scale. www.fotomancamera.com
Focusing for idiots (thought morons was a bit much), me included
I had posted this image to another thread about home made cameras, but then deleted it. I'm posting it again as the band width is now clear. The focusing is done simply by moving an inner box inside an outer box. Parts were taken from a Polaroid 110 camera. The gasket mounted in the inner surface of the front of the outer box is "fuzzy velcro," while the gasket on the outer side of the back of the inner box is "fuzzy velcro." The lens board is mounted on the inner box after the lens is mounted on it, and keeps the box from sliding into the camera. The velcro keeps the boxes from sliding past each other as the lens is focused at closer distances. tim
P.S. This is the best explanation I can give. Draw it on paper and you will see how easy it is to make and use.
P.P.S. Uploaded image to technical gallery, not sure why it wouldn't load into the thread.
Last edited by noseoil; 06-02-2006 at 07:23 AM. Click to view previous post history.
"whatever the solution is it will have to be low profile ..."
This constraint would not exist if you could find a helical focuser whose inner diameter is wide enough to accept the rear cell of your lens. Since I do not know the exact specs of your lens I cannnot be certain, but I think a Pentax 6x7 "Helicoid Extension Tube" with a max.outer diameter of 89mm should be adequate to accept a rear cell of only 55mm dia.
And with a minimal extension of 32mm ( max. 52mm) you wouldn't risk vignetting.
There is some information about this "tube":
The good thing with helical mounts ( apart from not being limited to pre-set distances): No trouble with collimation.