- With this adapter, you can use M39 Lens on Canon EOS R camera. - There is no electronic element in the adapter, aperture and focusing must be manually control. - Infinity focus is guaranteed. - Material: aluminium. - Please installing / uninstalling the adapter after turning off the camera. - Fine finishing! Install, remove and operate lens smoothly! - Although the lens will fit physically, automatic diaphragm, auto-focusing, or any other functions will not operate correctly while using this adapter.