WilsonFlyer wrote in post #18788088
Canon NAILED that adapter (and they could and they knew they had to) and there's very little credit given for it. All my EFs and EF-Ss work as well or BETTER on the R than they do on any of my other Canon bodies.
There is no limit to how well future bodies can see AF and attempt to drive older lenses, speaking their native protocol. This isn't like Sony bodies talking to Canon lenses with an interpreter slowing down and confusing the talk. The only permanent limit is the AF motor speed play in the lenses that may need a reverse of direction for final adjustment.
What you are reporting seems to be true for static subject use, especially in poor light and/or high open f-ratios. For following active subjects around at f/2.8 - f/5.6 with AIServo in good light, people don't seem to be quite as impressed. It would be nice if newer DSLRs could transform between EVF and OVF, and have R-like sensor AF and DSLR-OVF AF, each used when it is best for the context; both through the viewfinder. Rear LCD for narrow fields of view, hand-held, is a disaster.
I'm sure I'll buy some RF lenses over time as I commit further to the platform (and I am 100% committed to this platform), but right now, I have very little motivation or real incentive to start replacing anything I have. It's worth noting, I believe, that all of my glass is G1. I don't own any G2s or G3s aside from my two extenders.
Going to a higher MP count or to AF that is better for your situations is worthwhile, even without upgraded glass. Upgrading glass is an opportunity, not a sensor-created necessity. An old lens with more veiling glare and softer image corners still gives better results when you increase your pixel count from lower than 30MP.