Review on Fotasy Canon FD Lens to Canon EOS RF Mount Metal Adapter: Perfect Fit for Canon FD Mount Classic Manual Lens & Canon EOS R Mirrorless Camera EOS R/RP/Ra/R5/R6 by David Golden

PLUS: This adapter is great if you have some old Canon FD mount lenses. In my case I had 20mm f2.8, 135mm f2 and 500mm f8 SLR lenses. The latter is the real reason I bought it. I've always loved my old SLR lens and now I have a way to use it again without any extras (which was required for the EF mount). It's almost like beating a native lens (and f8 is the only aperture). A HUGE plus for the EOS R is that with manual focus you can use focus peaking and really fine tune the focus - which is even more difficult with my old FD cameras and of course with newer cameras like the Canon EF. CONS: Good, that I bought it for general use with my 500/8 because that lens only has one aperture. On my other two old FD lenses, the aperture DOES NOT WORK. I can only shoot wide open. You're supposed to be able to adjust the aperture and aperture, but at least my adapter doesn't. I have other more modern 20 and 135 EF lenses so this is not a problem for me.