I have a 5D III ... I don't shoot sports but I can offer some info.
First and foremost... if you don't already have this (becuase it doesn't come with the camera), go to this page and in the lower left corner is a link to download the Canon guide-book on the AF system that your camera has. It's a 47 page book on JUST using the focus system on your camera. It says "1D X" but if you read the page you'll see that it was really intended for the 1D X and the 5D III.
http://www.learn.usa.canon.com/resources/articles/2012/1dx_guidebook.shtml
Next, Rudy Winston (Canon USA) has a video series on using the new features of the 1D X (in 5 parts) and the first 3 parts explain features of the auto-focus system:
Part 1: http://www.youtube.com/watch?v=DM6KkQcNI8w
Part 2: http://www.youtube.com/watch?v=X4dDzIDB6_A
Part 3: http://www.youtube.com/watch?v=Z7n2cWfLk8s
You want AI Servo -- since your subject distance may be changing and this provides for continuous focus.
Evaluative metering is fine since this will evaluate all metering zones.
Shutter above 1/1000th is also fine -- this will freeze action
On the custom controls, each of the ten options will tell you what the camera will do when you press that control.
For example: You might want to use "back button focus" behavior. For this you would set the "Shutter button half-press" behavior to "Metering start" (not not AF), THEN set the "AF-ON" button to "Metering and AF start". This way the camera will ONLY focus if you press the AF-ON button with your thumb.
All this is probably not necessary with the 5D III's focusing system because the whole point of you picking "Case 2: Continue to track subjects, ignoring possible obstacles" is that it eliminates the need to configure the camera for back-button focus. It's one of the benefits of shooting with a 5D III or 1D X body. With any other body... you'd configure back-button focus behavior.
Your "AI Servo 1st image priority" and "AI Servo 2nd image priority" control whether the camera uses "focus priority" (wont shoot until focus is confirmed) or "release priority" (will shoot when you press the button whether it was focused or not) or a blending of the two. The "AI Servo 2nd image priority" affects the behavior of all subsequent frames after the first frame when using continuous shooting mode.
Selectable AF point - 61 points means the camera is allowed to use ANY of the focus points to lock focus. Keep in mind that the camera will gravitate to the nearest subject when using this mode. If other players are closer than your son and you want to make sure the camera focuses on your son then you'd want to use a different focus mode to narrow the area where the camera looks for focus.
The "AF area select mode" doesn't affect shooting... when you decide to change focus modes, you can switch off certain focus modes you don't ever think you'd use. For example... if you have two favorite modes and you just want to swtich between them quickly, you can turn the other modes off. That way you don't have to keep pusing the button to change focus modes until the mode you want appears (because each time you push the mode change button it cycles to the next mode.)
AF area selection mode - main dial. that just means when using a mode OTHER than the 61-point AF mode (where you just want to use some points) the way you'll tell the camera WHICH points you want to use is by turning the wheel. I use use the 8-way navigator on the back).
Orientation linked AF means that if you tell the camera you want to pick some focus points in, say... the "upper right" corner and you are holding the camera level (horizontally)... what should it do when you turn the camera on it's side? If the orientation is NOT linked, then the points you pick are the points you pick regardless of the camera orientation. If the orientation IS linked, then it means your selection of points in the "upper right corner" is will be maintained... so when you flip the camera on it's side, it'll automatically swtich AF points so that the poitns are STILL in the "upper right corner".
The manual AF point selection pattern tells the camera if the focus points should "wrap around" when you keep navigating off the edge of the screen. e.g. I use joystick... so this means that if I'm already on the right-most AF point... and I nudge the joystick right one more time ... it'll actually "wrap" back around to the left edge. If I turn this off then when I hit the right edge and nudge to go right one more time nothing will happen (because I'm already as far to the right as it can go.)
Get out and practice with the AF system controls -- it takes a bit of learning but you'll find it's quite powerful and once you get the feel for it you will really appreciate having it.
Tim Campbell
5D III, 5D IV, 60Da
