Originally posted by BigMackCam Mine is a tight fit too - much tighter than the original Pentax adapter. It won't rotate into place using finger pressure, but needs the tool to fit and remove it. The benefit of this is that you don't get any "wobble" with lenses that don't press up against the camera's own lens mount - lenses with narrow "necks", such as the old Helios-44 and 44-2, for example.
Before you start sanding or filing away material, place the adapter flat in the mount and, using the correct tool, try just a little more force than you might expect should be necessary. I think you'll find it should move into place, albeit quite tightly
It really was too tight to move so I set about it with some very fine paper, so fine, you could use it to wipe your b...... Anyway, 20 minutes later, it fits, albeit still snugly. It also works brilliantly
and without a credit card shim
it still needs the tool to fit and remove but we have a winner
I. Have tested it with a czt, a Helios and a tak and all appear to shut down perfectly
time to take some photos