How is EF lens AF performance on R bodies?

Really thinking of buying the R5 when it launches.
I have a bunch of EF glass that i am very happy with and not too keen on replacing (from a financial point of view) so i was wondering how EF lens AF performance is on the R bodies?

I currently have a 5dIV, a Sony A7R3 and a Sony A9. The Sonys have the Sigma MC11 adapter.

The A7R3 is ok on AF, just fine up to 100ish mm focal length but virtually useless with my Canon 300 F2.8
The A9 is noticeably better and can handle Canon 70-200 F2.8 just fine but also struggles with the 300 (though it actually can land focus with it unlike the A7R3)
The 5dIV is obviously better with all the EF glass than the Sony cameras.

Since i would need to use an adapter with the R camera i am worried about the AF performance. I have read that since the camera, adapter and lens are all from Canon it would be native AF performance but i can't find any facts backing this up. Surely with an adapter between the lens and the camera there is a tiny performance loss?
 

AlanF

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Aug 16, 2012
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"Surely with an adapter between the lens and the camera there is a tiny performance loss?" Canon Lens-wires-Canon body; they are both native Canon speakers with compatible Canon hardware and firmware. Canon Lens-wires-chip-wires-Sony body; AF depends on the chip processing the data and overcoming incompatibilities in Sony and Canon hardware and firmware.
 
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Mar 14, 2012
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For portraits with thin DOF, the R kills the 5D4. Focus accuracy is better on the R. With eye detect, the R is even better. More difficult lenses (i.e. 50L) are much easier to use on the R and the hit rate is much higher.

I've adapted the EF 24-70 f/2.8 II, 70-200 f/2.8 IS II, 100-400 IS II and 300mm f/2.8 IS II onto the R and the focus is like native. R servo AF is worse than 5D4, which is why I've kept the 5D4 around. With the R5, I'm hoping to get out of EF bodies for good.
 
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My lens AF seems to be the same speed. Balance is affected due to the tube, the low light capability is better if you compare the same amount of light , I often use my R and my 5D MK IV side by side in low light events, virtually no detectable AF difference. The R can autofocus in lower light, and AF speed does slow down, but then, my 5D MK IV can't AF at all in that light unless I put it in liveview and then, it still struggles a little more.

I have a grip on my R which may provide more current to the lens? That could make a difference, but I've not tried to compare.
 
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