Topic: Nikon to EOS adapter from Roxsen, modifications
I now have 2 of the above adaptors and they have proved to be very good, they are made from plated brass and seem quite sturdy, they focus very slightly past infinity which suits me fine. However both have suffered from the same design fault.
The circular spring between the adaptor body and the front ring does not sit flat causing the front ring to be misaligned. If you look closely at the front ring you will see that although it fits down tightly where the fixing screws are, it is slightly raised at the points where the Nikon bayonet springs are located. As there are 4 fixing screws and 3 bayonet points this could be tilting the lens slightly.
The reason for this is that the curved edge where the bayonet spring is formed hits the sharp inner edge of the adaptor body so preventing the ring from fitting down correctly.
The answer is quite simple, remove the front by taking out the 4 screws, being careful not to lose the small spring that is under the lens locking pin, and file a small slope on the edge of the adaptor in line with the bends of the spring. Reassemble and the problem should be gone. On one of mine I found that the front ring was slightly deformed because of it's original ill fit but this was soon overcome by giving it a slight bend in the opposite direction between the screw holes, once screwed down it was then perfectly flat.
The offending gap
The curved edge of the spring hits the edge of the adaptor
Edge filed off.
Only a minor problem, but well worth fixing.