EOS R AF Sensitivity - A comparison

So took my new EOS R to a party tonight and compared its AF sensitivity to my Sony A7RIIi and was really impressed on how it focused  in low light compared to the Sony. I know this is not the best Sony to compare to because I know my a9/a7iii/a7riv specs state they are about 1 stop faster offering -3 EV at ISO 100 and f/2.  When I look at the Canon and work back from the -6 EV spec at f/1.2 (which I assume is also at ISO 100) I think the Canon would be -4.5 EV at f/2 if my assumptions are correct. That is a full 1.5 stops better and the a9/a7III/a7RIV and 2.5 stops better than the a7RIII I was using.

Using servo with face/eye-af the Canon seemed to hunt less and capture focus faster and be more sure of itself. Now on the Sony I had the GM24-70 f/2.8 and on the Canon the RF 24-105 f/4L and still the Canon seemed quicker. That one stop difference in lens aperture on the Sony did not help it beat the Canon combo. My shooting aperture on both was f/5.6 since I was using flash and wanted that depth of field improvement since I was shooting couples and wanted to ensure both faces were in focus.

Now I think one other difference that I need to look at was that focusing aperture. On Canon my experience has always been that AF is always done a the lenses maximum aperture. On Sony though some lenses focus that same way and some other like I think the GM 24-70 actually try to focus stopped down to shooting aperture. I have to go back and check this out.

Either way, if this proves to be the case the Canon may earn its place back in to my shooting if in low light it is a better and smoother AF.

Now the down side. I did notice that the Canon has delay since I never saw the flash go off through the view finder. I could tell from the color temperature of the viewing vs the final captured image. On the Canon they alway mismatch and I never saw the image I actually captured in the viewfinder while it was up to my eye. The Sony did not have this issue and was quicker to respond. Had this opposite results back when I used to shoot with my 5D Mark IV with the optical viewfinder when compared to the Sony.

So just thought I would share some feedback of my flash experience with the EOS R vs the Sony A7x family. Certainly more testing to do.