I bought an adapter for 15 bucks from Amazon that allows me to put my vintage Minolta Rokkor lenses onto my Canon EOS R5. I'm surprised how well built/machined it is at that price and the lenses and adapter all fit together nicely - not too loose, not too tight. There are no electrical contacts so it is basically a piece of plastic with metal mounts on each end. The camera doesn't even realize there is a lens on so you have to go into the menus and set it to let you fire the shutter without a lens. Then everything works as it would with a manual lens - except for the auto-diaphragm. Basically you set the aperture on the lens, manually focus and set everything else in camera. I don't see why the camera couldn't confirm focus like it does when a regular Canon lens is on the camera in MF mode but it doesn't - so focusing can be a little tricky as it is purely visual. That being said since it is a mirrorless camera you can zoom in. Nothing about this set up is quick - but it is just a fun way to use some of my favorite lenses for hobby work.