CHSE,
Nice work. I added a pentax mount to my Olympus/Cosina 28-70 F2.8 zoom. It works great and now I need to add a diaphiam coupling arm and light baffle. The registration distance is 46mm on the OM lenses which is greater then the 45.6mm of the Pentax. I used a the M42 adapter which has a 0.6mm flange. This added just the right amount of spacing. Here is a list of the various distances of SLR's. As you can see the Nikon is a good canadate at 46.5mm.
Registration Distance
(data from internet sources)
Pentax 45.5mm (K mount and M42 screw)
Nikon 46.5mm
Olympus OM 46.0mm
Evolt 38.5mm
Minolta 44.0mm ( actual measurement by me)
Canon FD 42.0mm
Canon EF 44.0mm
Leica R 47.0mm
Konica ?mm
Topcon 44.7mm
Dave
Last edited by Big Dave; 08-10-2008 at 03:44 PM.