[Rainer]

The old Canon R-mount has (to my knowledge) the same short

register-distance (of 42mm) that Canon FD has. Therefore

you cannot (!) adapt it to EF without either losing the

ability to focus to infinity or with using an adapter with

an additional glaselement (which especially decreases

the optical quality of glases with large rear elements).

 

Likely you buy an expensive paperweight.

 

Just my 2 cts ... Rainer

 

PS: I assume you mean this lens:

http://www.canon.com/c-museum/en/product/r76.html