Several third-party companies make adapters for various lens mounts to the RF mount. These tend to work the same as manual focus lenses do on the Canon adapters:
- Shoten — Leica M (LM-CR), M42 (M42-CR), Nikon F (NF-CR), Canon EF (CEF-CR), Minolta MD/MC (MSR-CR), Contax (CY-CR), and Leica R (LR-CR)