Use your Canon EF and EF-S lenses on the RF mount EOS R CSC with the
EF-EOS R mount adapter. This particular adapter also has the added
benefit that is also adds the ability to use drop-in filters, making it
possible to use filters on wide-angle or large-fronted lenses.
This adapter comes with Canon's Drop-In Varaible ND Filter A. Other
filters that are available include a circular polarising filter, and a
clear filter (sold separately).