RE:Mikro-Nikkor 55/3,5

[Eertmans Nicolas]

Mathias,

your lens must be an original non-AI Nikkor which has been
"factory-"converted to Ai. I have a 35mm f/2.8 that has been similarly
modified by the Nikon service: the original aperture ring has been
replaced by one with automatic indexing.
For what the RR concerns, I think old Micro-Nikkor have two scales
engraved: on for usage w/o the extension ring, one with.

Hope this helps,

Nicolas.