Replay: If you do, then Canon USA has a video for you that shows how autofocus went from 'the function that shall not be named' among professional cinematographers to a cutting edge tool that can really deliver.
According to the company, on current Canon models 80% of the area from the centre outward that you see in the viewfinder is covered by Dual Pixel AF. The neat little animation below describes how it works. And we did rather like the caption where the client is looking at footage in post and simply saying: "Who the &#$% shot this!"
Looks like it might be time for AF to come in from the cold.