Canon Mount Adapter EF-EOS RCanon Mount Adapter EF EOS R The standard Mount Adapter EF EOS R allows EF S and EF lenses to be used on EOS R cameras seamlessly. Photographers who already have a collection of EF S or EF optics can invest in the EOS R System confidently, knowing their existing lenses will work as expected. Bring your EF S lenses to the EOS R System EF S lenses are designed for APS C sensor EOS DSLRs, but they can also be used on EOS R cameras via adapter. The camera