# Problem with AF with R5 and EF 500mm f4 mk1 and converters...



## rico.29 (Oct 29, 2021)

hello every body,
after a few issue with my R5 and 500mm f4 mk1, with AF, everything went perfectly in order,
no more issue, even with EF 1.4x converter.
I use official RF-EF converter.
firmware is the last.
I recently bought Canon EF converter x2, tried it with 500mm and R5 with no problem, even tried 2x + 1.4x converters, no problem, AF worked.
I switched lens and came back to 500mm with converters and... no AF at all (servo or one shot), mount the 500mm with no converters and ... no AF, tried 500mm +1.4x, no AF.
switched back to RF lens, AF is perfect, swithed to another EF lens (sigma 105mm 1.4 art) and no problem with AF.
But still, no AF with 500mm f4.
i reset the R5, nothing change, reinstall firmware, nothing change.
what's the problem here?
thank you for your help.


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## bernie_king (Oct 29, 2021)

This is a bit of a silly question, but did you check the AF/MF switch on the lens? I bumped mine once without realizing. To compound the confusion the switch had disappeared underneath the lenscoat. If that's not the problem, try cleaning the contacts on the lens.


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## rico.29 (Oct 29, 2021)

yes  , first thing i've checked.
try with or without stabilization (who knows?), different AF distance on the lens, every AF setting possible on the R5, no AF.
I've cleaned the contactor of the lens, nothing change.
what's really struggling me is that i've test the 500mm f4 + EF x1.4 + EF x2 +EF/RF +R5 and AF was preatty good.
i've to test the lens on EF camera.


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## neuroanatomist (Oct 29, 2021)

rico.29 said:


> i've to test the lens on EF camera.


Indeed, it is possible (and I'm sorry to suggest it) that the AF on the lens failed. 

The only known incompatibility of the MkI IS 'great whites' (200/2, 300/2.8, 400/2.8, 500/4, 600/4, 800/5.6 and 400/4 DO) on an R-series body is that the AF Stop buttons don't work via the adapter (source).


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## rico.29 (Oct 29, 2021)

yes, AF may failed, that's why i would like to try the lens without converter on a EF body camera first.
what's really strange is that it happens all of a sudden.


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## neuroanatomist (Oct 29, 2021)

Failures are often like that.


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## rico.29 (Oct 31, 2021)

in fact, it's just as if the lens does not know if the subject is in focus or not, the AF has an heratic behaviour, it keeps try to get focus.
As the lens is much holder than the R5, i wonder if it would get normal AF , mounted on a EF camera, may be the focus of the lens would get its "mark".


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## neuroanatomist (Oct 31, 2021)

You either have to find a way to test it on another camera, or send the lens into Canon for service (if they will still service that lens).


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## rico.29 (Nov 1, 2021)

I've tested it once again on the R5, i did not do any change and... AF is back, well at least till 10-12m , it's perfect but if i aim to a futher subject, AF is heratic again, and do not spot on the subject. Subject is for a while in AF but it constantly jump.
I switch several time from "4m to infinity" , to "10m to infinity", nothing change.
may be this is a "lazy" lens?


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## Daniel Godin (Nov 5, 2021)

Bonjour j'ai également le problème de l'AF qui bloque avec mon 500 mm canon f4.
C'est très frustrant de voir l'oiseau flou sur la branche et ne pas pouvoir obtenir la netteté.
Je suis équipé du r6 et d’autres photographes équipés du r5 ont les mêmes soucis !!! Pouvez-vous me donner la marche à suivre pour régler mon problème ? Merci à tous et à bientôt vous lire…..


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## rico.29 (Nov 6, 2021)

Daniel Godin said:


> Bonjour j'ai également le problème de l'AF qui bloque avec mon 500 mm canon f4.
> C'est très frustrant de voir l'oiseau flou sur la branche et ne pas pouvoir obtenir la netteté.
> Je suis équipé du r6 et d’autres photographes équipés du r5 ont les mêmes soucis !!! Pouvez-vous me donner la marche à suivre pour régler mon problème ? Merci à tous et à bientôt vous lire…..


glad to see this AF problem on R5 + 500mm f4, is known by others, i was beginning to think my lens was faulty.
but sad for the owners too, because it's very frustrating...


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