Upload & Sell: Off
Peter, what lenses are you using when you notice this?
I also set my cameras to a longer delay before going to sleep.
Regarding your second point: I just did a basic AF comparison at home between the X, IV and III. Obviously this is different than BIF, but might be informative. Using the center point, with a lens like the 70-200 f/4L IS, at 200mm, focusing on very dark folded textiles where there are some areas with contrast and other areas with no contrast, all of the cameras have trouble finding focus in AI Servo, but when there is sufficient contrast, it seems the X and III lock more reliably. The IV isn't that far behind. With the 135L, not surprisingly all focus more reliably/faster. There really doesn't seem to be a huge difference between any of them with AI Servo and initial focus acquisition, but as mentioned, would rank the X and III a bit ahead of the IV for initial acquisition. But this is in really low light and low contrast, in the ISO 1600 1/30 f/2 range. Most of my low light action shooting is done in stadiums, with the worst being here in Hamilton at ISO 3200 1/500 f/2.8, which is four stops brighter than this mini test at home. I have yet to try the X in this situation, but the IV and III have generally been OK, though when a team is in a dark uniform, sometimes the cameras have trouble maintaining AI Servo tracking, as a result the fps drops (I have the cameras set for focus priority on second and subsequent frames) and focus consistency decreases.
From this mini test, the biggest difference between the three is in One Shot. Aiming at an extremely low contrast area of black textile, in an area about a stop lower in light, only the X will lock focus. With the f/4 lens it will lock in two stages. First coming close, then taking about half to a full second to confirm the lock. With the 135L, AF lock is instantaneous.
I suspect some aspects of the AF tracking performance will be lens dependent. With f/2.8 and faster the central stripe of sensors should be better. But of course with BIF, you're probably at f/4 or f/5.6 to start and will lose the second cross sensor array on these points. I also wonder what your AI Servo 1st image priority and 2nd image priority settings (in pink AF2:AI Servo tab) are? Those shouldn't affect AF initiation speed, rather, image capture, but you never know... I've left both at equal until I get a better feel for the X. With the IV and III I always went for release priority on the first frame and focus priority on subsequent frames.