Lens adapters to put Canon EF mount lenses onto M mount bodies are nothing new. Canon’s had one for a while now. But when it comes to speedbooster style adapters, one company’s pretty much had the market sewn up, and that’s Metabones. But Metabones only produces such adapters for Sony, Micro Four Thirds and Fuji crop cameras. At least for now.
A new Japanese patent (2018185393) suggests that Canon will be working on their own, now, though, breathing some new life to their EOS M mount line of cameras – as well as their EF mount lenses as they make the push towards full frame mirrorless.