R5 Question Regarding RF and EF Lenses

Started 3 months ago | Discussions thread
RDM5546 Senior Member • Posts: 1,352
Re: Thanks but not everything has been answered about EF and the R5/R6

R2D2 wrote:

David Franklin wrote:

Thanks to all of you who have answered the OT's and my questions about the new RF cams and IBIS with EF lenses, but not everything has been answered about EF and the R5/R6.

My additional questions revolve mostly around this: do the EF lenses, using the new Dual Pixel 2 and Digic X, plus improved algorithms with deep learning in the R5 and R6, auto focus as quickly, as accurately and specifically (eye, head body, animal, etc.), and with the same much improved stickiness - despite movement and foreground/background clutter and greater subject distance - as their new RF cousins? And if they don't, just how much less well do they perform? Half as much better? 25%? Almost as much? Not at all? Are the new camera mounts, in-lens circuitry and drives in the RF lenses necessary for communications that enable these things at all or do a lot of these better focusing behaviors still accrue to the EF lenses anyway? I think these questions are even more important than those questions about IBIS.

Thanks in advance to anyone here who has some real answers and can let the rest of us know.

+1 My thoughts exactly. Not only IBIS, but AF too.

Because for me it really comes down to whether or not I'd also need to buy the new 100-500 to replace my 100-400ii + 1.4x iii to get all those wonderful AF goodies found in the new R5/6 (and at the same effectiveness).


No one is likely to give a satisfying or accurate answer to question.  Only careful testing of the AFII on the R5 or R6 will reveal that for the EF lenses tested.   No one can guarantee it will work on third party lenses either. Lot of unknowns here.   We do know that 8 stops of stabilization does not work equally well for all Canon RF lenses. Some are a little less and non L RF lenses are reported by Canon to be 5 1/2 stops  (24-240.

We have to wait for user feedback about AFII using  specific RF and EF and third party lenses on specific type of subjects and what they focus on and what type performance they give.  The answer will not be black or white but hint at whether the tester happy with what he got or not and that will also depend on the tester.

I have a biggest enough confidence and need to justify my preorder or R5 and others will be different and wait for the reviews to trickle in over the next year or until the Christmas sales.   If the cameras are selling well then the first Christmas savings may be less the second Christmas.  Such has been the way of every big camera announce before.  All of those earlier cameras had limitations in the end and I pretty sure these will too.

Independent user feedback will help but to trust it get your answers from mutiple sources may take six months or more. The EOS R is now almost two years old and we know from the forums pretty well what people think.

I for one think the EOS 100-400mmL ii will work pretty much like the EOS 100-500mmL and in fact it might even work a little better than particular lens comparison because I expect they both are excellent lenses creating good images but the 100-400mm is likely brighter at 400mm than is the RF 100-500mm lens.   However, I do know what the f number of the f number of the RF lens actually is at 400mm despite the speculations that are widespread on the Internet.  Canon has not published this speculation.

If you are concerned about this issue then wait for more independent data.  I am not concerned and I expect my EF to AFII work very well but maybe not all will be that way.   Then I will buy what better.  I suspect not all the RF lenses will perform as well as the best ones. New lenses may come out to work better.

I am nor indifferent to this question about AFII and I know the AF will not always work as well as it is shown in the demo video we have seen.  I will learn about the system limitations by using for type of shooting and I know the R5 should better than my current EOS R which is better than my EOS 5D Mk IV.    What that means today is based on prior experience with Canon products and it is also part guess.  I know that devil is always in the details and we do not yet have some those details   I now have a lot of experience from using the EOS R first hand for around a year.

It is safer to wait for independent testing, by owners and reviewers. I wish you luck.

 RDM5546's gear list:RDM5546's gear list
Canon G5 X II Canon EOS 70D Canon EOS 7D Mark II Canon EOS 5D Mark IV Canon EOS R +31 more
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