Looks great Robbie it takes a bit to get use to but you can manually shoot on the fly if you use a high FSTOP. I am using the Mark II but the same rules apply.
Here is a handheld scene where I shoot the video at f11-f14 which makes is easier to focus while moving around. You also want to use a wide prime for getting stable shots handheld. The longer the focal length the harder it is to keep the shot steady.
http://nubiles.net/nina_james.html
Here is some video shot with 2.8 aperature for a more short depth of field. The camera is on a monopod and there are some slider shots. Short depth a field it not easy to shoot when moving around. This is why when you shoot sex scenes you need 2-3 cameras to get all the action. One camera should be dedicated for closeups and the other footage stationary angles so you always have good shots to cut to. These shots are from a Canon 70-200 2.8 L
http://www.jayrockcontent.com/blog/?p=281