Canon R5c video mode AF and 3rd party lenses

[Ron Wilk]

I'd received my R5c some weeks back. Prior to its arrival, I had ordered a Tamron EF 24-70mm  F/2.8 USD G2 VS... lens to be used with my C300 Mk III.  I'd already owned the Canon version, but I'd wanted the OS offered by the Tamron and not by the Canon. The lens works fairly well—AF included—with the Mk III, but it will not autofocus on the R5c in video mode.  An owner of several other Tamron G2 lenses has stated that his various EF mount 'G2' lenses do not AF—in video mode—on the R5c either.  I am therefore wondering if the Sigma EF mount lenses present with the same AF problem?   Any owners out there???

Edited April 21, 2022 by Ron Wilk
Grammar

[Tyler Purcell]

Does it not try to AF at all? That's odd. I've not seen that behavior before. I know on our older EOS lenses, it does not like to AF on video mode, but it always tries on our R5. I wonder if that function is entirely disabled on the 'C' because it worked so poorly on the R5?

 

[Ron Wilk]

10 minutes ago, Tyler Purcell said:

Does it not try to AF at all? That's odd. I've not seen that behavior before. I know on our older EOS lenses, it does not like to AF on video mode, but it always tries on our R5. I wonder if that function is entirely disabled on the 'C' because it worked so poorly on the R5?

It is completely inactive in video mode, and has been confirmed by other R5c owners.  It will allegedly work, however, in photo mode—I do not use photo mode but plan to try it.  I have no problem with older Canon EF lenses in video mode and, as mentioned in my original post, it functions just fine on my C300 MK III.

BTW, Tamron support seemed disinterested, as they'd commented that they do not test their lenses on CINE cameras.  Therefore, I do not anticipate any firmware fixes from them.

 

Edited April 21, 2022 by Ron Wilk

[Ron Wilk]

FYI: A conversation with a Sigma representative has revealed that their lenses will Autofocus on the R5c in video mode.

[Ron Wilk]

After much internal debate, I'd decided against the Sigma and purchased the Canon RF 24-70mm F/2.8 IS.  So far, my testing has shown that the lens is sharp across the focal plane at all apertures, while sharpness increases towards F/4-5.6.  AF is quick and accurate in video mode, and the control wheel is a welcome feature that I have set to ISO.  

[Tyler Purcell]

Good decision Ron. 

[Ron Wilk]

11 hours ago, Tyler Purcell said:

Good decision Ron. 

Thank you, Tyler.

[Gino Demurtas]

Hi, I just bumped into this forum looking for solution about my Sigma lens with my Canon R5c.

So, I have a moderately recent 17-50 2.8 that works correctly in video mode, and another two lenses (70-300 , 8-16) that works in photo mode, but not in video mode.

I have sent both lenses to Sigma, they updated my firmware, but unfortunately they both don't AF in video mode.

I have also contacted Canon, and they said they contacted the firmware department to see if they will create some compatibility in the next update.

I think, the compatibility factor comes from how old is the lens, but there is no way to be sure.

There is a list from Sigma of the compatible lenses (for R series), and they say the 8-16 is compatible, but in reality, it isn't.

So yes, just wanted to share my experience in case someone has the same lenses and thinking about upgrade.