A Nikonian, leading a group on Segways, stopped behind me, near where I was seated on a bench on a small hill with a non-functional lighthouse with my camera on a tripod, facing away.
We finally made eye-contact, and he asked "What kind of Canon is that?" Apparently, the 800mm mirror lens hanging off the front intrigued him.
I said "this?" and partially turned it toward him, and he mumbled, "What Canon -
oh, it's not a Canon." I said (pointing to camera) "is a Pentax, and this" (pointing to lens) "is a Vivitar".
I explained the focal length, let him look though it, said it was so-so quality but a fun and cheap alternative to other (unobtainable) long glass, and could be used with a Nikon T-mount.
Then they left.