Based on a quick calculation, your lens might be approximately 0.122 mm closer to the film plane than if it were positioned perfectly (given that the adaptor was machined within tolerance), like say a Leica M lens (your lens seems to need a 45 degree extra turn to lock it securely and the Leica thread mount is M39 with 26 TPI). I would do a focus test wide open at 1 meter distance this way and also with a thin shim between the lens and the adaptor to see if there is a difference.
Let us know if you can see a difference with your enlarger's head cranked to the max.
Also, how is the infinity position WRT your camera's rangefinder?
EDIT: After looking at a few photos of mounted Summarits, this sort of misalignment actually appears to be rather typical:
Do the focus test, it will tell more than an hour of theorizing.
Last edited by Aron; 01-09-2012 at 05:44 AM. Click to view previous post history.
Reason: Clarification, expansion.