Quick question to see if anyone knows what the problem could be
Canon R5 C camera with the EF->RF adapter (the one with the control ring) plus a Sigma EX series 10-20mm lens. This is a crop sensor lens.
when I use this combination together in video mode the camera says the lens is not compatible. the aperture value cannot be read and cannot be changed, Autofocus will not work etc. However without changing anything in hardware if I switch the camera into photo mode it works just fine. Anyone know what could be going on?
One other note even in photo mode the camera did not recognize this lens as an APS-C format lens so I had to change the setting manually. other Sigma lenses which are APS-C format are recognized as such automatically and the camera is put into crop sensor mode. I don't know if that means anything but could indicate a minor incompatibility which I hope could be corrected in the future.
Given that the lens is third-party, and isn't recognised as crop, I would guess it's not fully compliant with the EF communication protocol standard. Which isn't too surprising, as there really isn't a standard; it's a mish-mash which has changed over the years.
Since the R5C really has two different operating systems, it's not a huge surprise that the two sides treat an alien lens differently.
I wouldn't be surprised if this lens works generally with Canon stills cameras, but has issues with their cine cameras. If true, that would mean that Sigma haven't done the full job of making this lens compatible -- again, since they're reverse-engineering the protocol from scratch, not a huge surprise.
See if Sigma have a firmware update for that lens.
Have you turned on Lens EF-S mode in the video menu? I assume it's there. On the C70 it's in the first tab (Camera Setup) at the bottom of Page 6.
But yes, AtticusLake is certainly correct above that ultimately, it's a Sigma lens issue. Do you have the Sigma USB dock? There may be a firmware update for your lens.
Sigma docks only work on Global Vision lenses. Art, Sport and Contemporary.
This EX series lens is about 8 yrs. There are 2 variants and are not included.
Both also have the following limitation. * Vignetting will occur if the lens is used with digital cameras with image sensors larger than APS-C size or 35mm SLR cameras. Fair to say its lucky it works in Photo mode.
Bay Area - CA
~R5C (18.104.22.168) ~Many Lenses ~DxO PhotoLab Elite ~Windows10 Pro ~EVGA RTX 3080Ti FTW3 Ultra
~ImageClass MF644Cdw ~Pixel6 ~6D2 (v1.1.1) retiring
yes, I bought it new 2-3 years ago but its been discontinued. Unfortunate, its a pretty good lens I wish I could use it on this camera. It just puzzles me that in photo mode it works but in video mode it does not. I guess it really is like two completely separate cameras hybridized into a single body. Pretty remarkable actually. I think the solution is going to be investing in an ultrawide RF lens and keep the Sigma on my DSLRs