FotodioX Type 2 Pro Lens Mount Adapter with Generation v10 Focus Confirmation Chip for M42-Mount Lens to Canon EF or EF-S Mount Camera

The FotodioX Type 2 Pro Lens Mount Adapter with Generation v10 Focus Confirmation Chip for M42-Mount Lens to Canon EF or EF-S Mount Camera listed above is designed to connect manual focus screw mount lenses with M42 threads (such as Pentax screw-mount lenses) onto the Canon EF lens mount used on their DSLR cameras. It is not compatible for connecting EF lenses to the RF lens mount. If you need a lens mount adapter for EF lenses to be used on a Canon RF lens mount, the Canon Mount Adapter EF-EOS R, B&H # CAMAEFRF, the Vello Auto Lens Adapter for Canon EF/EF-S Lens to Canon RF-Mount Camera, B&H # VELAECRCEF, or the Commlite Electronic Autofocus Lens Mount Adapter for Canon EF or EF-S-Mount Lens to Canon RF-Mount Camera, B&H # COCMEFEOSR, would work and offer focus confirmation compatibility.

We do not recommend stacking adapters. Your results may vary.

As you are referring to using two different lens adapters at the same time (which is not how lens adapters are designed for use), I cannot guarantee using a M42 screw-mount lens on the above Fotodiox adapter, then connected to the Canon Mount Adapter EF-EOS R would retain communication to the camera. The best I can state is if you purchase the items and they do not work for your planned usage, you may return the lens adapter within 30 days of purchase date for a refund or exchange.