Poor AF performance on EOS R when recording with C-Log?

[Kit Lens Jockey]

I decided to try out shooting video in C-Log with my EOS R last night. (Fully knowing the editing it requires in post.)

It seemed like the AF performance when shooting in C-Log was much worse than normal video shooting. Granted I was shooting in low-light conditions, but without C-Log the AF worked well. With it turned on, the AF seemed to hunt around much more, even at one point completely blowing the video out of focus and then hanging up with the lens completely de-focused. I was using single point AF.

I know there are a few features that are disabled when shooting in C-Log, but I didn't see that there was anything published that stated that AF performance takes a hit, or dual pixel AF is disabled or anything like that. (Does the EOS R have any form of autofocus other than dual pixel AF anyway?)

 

[Bennymiata]

Seeing as you were in low light and how C log lessens the contrast, the sensor may be struggling to find enough contrast to focus properly.

 

[Kit Lens Jockey]

I guess that begs the question then, what is the camera actually using to focus? The raw data from the sensor itself, or the flat, un-contrasty image that results from the C-log being applied?