As anyone who follows the rumors sites probably knows by now, a third-party lens manufacturer has claimed that Canon told them to stop making RF-mount products. Fine and dandy by me, as I’m reasonably satisfied with my current RF choices. And–one never knows–there may be some proprietary factor that could be affected by third party glass, although I had no problem with an M-mount lens on my R5. If Canon wants to keep the mount all to themselves, more power to them.
BUT . . . maybe that’s why Sigma has been conspicuously mute in recent months about doing lenses for Canon mirrorless. AND . . . with Sony open to Sigma and others making lenses for E-mount, it’ll likely make a difference in some of my choices going forward. In fact, I can even use my EF glass on Sony, and it works just as well as it does on Canon.
Of course it makes a difference that, thanks to both Sigma and Sony, my a7 IV now has superb glass for shooting both short and long, while my long glass for Canon now looks a bit, well, slow. Limiting what I can use with full function on their cameras means that if Canon chooses not to make an affordable, moderately fast, long-enough telephoto lens, I’m stuck with what I have.
Unless, of course, well, you know . . . !