Amazon.com : Canon Drop-in Filter Mount Adapter EF-EOS R with Variable ND Filter : Electronics
Amazon.com : Meike MK-EFTE-C VND Drop-in Filter Auto-Focus Mount Lens Adapter for Canon EF/EF-S Lenses to Sony E Mount Cameras with Variable ND Filter and UV Filter A7SII A7 A6000 A6500 A7SIII