Jon555 wrote:
quiquae wrote:
John Sheehy wrote:
quiquae wrote:
Jon555 wrote:
They will definitely AF as-is, f/11 is fine for all DPAF, but I doubt you'll be able to add the extenders, especially the 2x, and have AF work (other than with a R5 or R6 that is).
Actually, I think you're wrong about that. Canon's official product pages for the extenders are now up, and they don't say anything about the extenders not working on R or RP.
It's not about the TC itself where there may be an issue; it is about the resulting open f-number. Canon says f/22 works on the R5 and R6, meaning that AF is reasonably fast and reliable by some standard. It is possible that the same f/22 will be more difficult for the R and RP, with more hunting in low light and low contrast.
EOS R actually has exactly the same low-light focusing spec (EV -6 @ F1.2) as R5, and only half a stop behind R6 (EV -6.5), which suggests that it shouldn't lag much the newer bodies in low-aperture focusing, if at all. But we'll see.
The question is will the R and RP focus at f/22, and I've never heard anything vaguely like that mentioned (just f/11, e./g. see the quote below). The issue is the size of the aperture rather than the amount of light you are getting.
"The AF points on the EOS R are compatible with maximum aperture f/11 at all AF positions (when used with a compatible lens and extender, such as the EF100-400mm f/4.5-5.6L IS II USM lens paired with a 2x extender). This makes AF possible even when shooting at a super-telephoto 800mm, dramatically expanding shooting possibilities for wildlife photographers."
F22 probably not. however, F22 is with a tele extender. F11 probably yes.
I seem to recall F16 being a limit, but to be honest after a while at this over the past week i'm lucky to remember my birthdate.