Best video autofocus settings for action sports

[theandies]

My son plays high school Lacrosse and is their primary faceoff guy (and he's really good at it and getting some buzz from collages).  My goal is to video every faceoff to create recruiting video's to send to the collages.  Yesterday they had a game and when I reviewed the video the focus would go in and out when the action started.  I'm using the kit lens (when I'm close, the coach lets me down on the field level at home games - EFS 18 - 55mm) and my telephoto lens (EF75-300mm ultrasonic) when sitting in the stands.

What would be the best AF setting for this kind of action?  My intuition after reading the manual is to use Flexizone - Single to focus on my son while in action.  We have another game Friday and don't have time to experiment so I call on the expert’s experience here to get a "quick fix". 

Also, is there a better lens for this type of action.  I like to zoom in to get better shots but don't want to spend a fortune (I know that limits me).  I also realize that a DSLR is probably not the best platform to create videos such as this.

Thanks in advance

[kvbarkley]

What camera?

You kinda answered your own question

"I also realize that a DSLR is probably not the best platform to create videos such as this."

[theandies]

T6i

[Waddizzle]

I think the best settings for video involves back focusing with a fully manual lens.

There are more unknowns besides what type of camera.  The T6i supposedly has "Full HD Movie mode supports Movie Servo for continuous focus tracking of moving subjects during recording," with manual exposure control....whatever that means.  I think it depends highly upon what focus mode you have set the camera for, as well as which and how many focus points you have selected. 

My best advice is to attend a few practice sessons and practice.

[kvbarkley]

The T6S is better for video focus, since it has better tracking. One of its few advantages over the T6i. Still not great, though.