Yo, I feel u on wanting to save some cash, but honestly? I've had some reallyyy bad luck with the budget brands. When I first got my R6, I picked up a third-party Viltrox EF-EOS R Mount Adapter and it was basically a disaster for my workflow. The fit was just slightly off, and it felt lowkey loose with my heavier L-series glass. I actually had the lens disconnect twice during a high-stakes shoot... seriously embarrassing lol. So yeah, I ended up biting the bullet and getting the official gear. Here is what I recommend for your setup: * Canon Mount Adapter EF-EOS R - This is basically the gold standard. It's built like a tank, has proper weather sealing, and the AF speed is 100% native. No electronics lag at all.
* Canon Control Ring Mount Adapter EF-EOS R - Highkey worth the extra cost if you miss the 5D dials. It adds that extra programmable ring to your old lenses.
* Avoid the cheapies like the Meike MK-EFTR-A EF to EOS-R Auto-Focus Mount Adapter. Those L-lenses are heavy and the mount stress on a budget ring just isnt worth the risk of a failure. Stick to first-party for reliability... trust me.

Ok so I'm usually pretty cautious with off-brand gear, but I've been reallyyy happy with the Meike MK-EFTR-A Auto-Focus Mount Adapter. Compared to those super cheap $50 adapters, the build is way more solid for heavy L glass. I think it’s the sweet spot! Honestly, it works just as well as the official Canon ones mentioned before, but for way less cash. No complaints so far! 👍

Would love to know this too

Can confirm this works. Did the same thing on mine and its been solid ever since.

Yep, this is the way

I think people focus a bit too much on just the physical fit, but there’s a bigger picture to look at if you’re doing market research on these. Honestly, the real gamble with going third-party isn't just if it'll fall off, it's the electronics and firmware longevity. Canon is constantly tweaking their AF algorithms with R6 updates, and since the budget brands basically just reverse-engineer the communication protocols, things can get buggy fast. I've seen plenty of setups where eye-tracking starts hunting or you get weird 'Error 01' messages right after a camera update because the adapter can't keep up. Also, something people rarely talk about is the internal flocking and weather sealing. If you’re rocking L-series glass, you’ve paid for that dust and moisture resistance, but most of those cheaper alternatives are basically a giant hole in your weather sealing. You're risking your sensor just to save a few bucks on a metal ring. Tbh, it’s less about paying for a logo and more about making sure your gear doesn't become a paperweight the next time you hit 'Update Firmware' or get caught in a light drizzle.

Late to the party but I gotta warn you about trying to fix the play in those cheap adapters yourself. I thought I could be clever and use some thin tape to tighten the mount on a budget one I had, but a tiny piece flaked off and ended up right on my sensor. Spent way more on a professional cleaning than I saved on the adapter. I should probably stop trying to be a handyman lol. I spent all of yesterday trying to restore an old leather camera bag I found at a thrift store. I used the wrong oil and now the whole thing smells like a basement and feels kinda sticky. My wife wont even let me bring it in the house... basically just ruined a perfectly good vintage bag because I watched one YouTube tutorial and thought I was an expert. But yeah, definitely be careful with the DIY fixes on gear.