iPad camera: how to trig autofocus or define exposure settings

I am trying to build a mini app to show the iPad 4th camera live to his screen (+ other functions).
I am started with the videoGrabberExample.
As I can see, the autofocus and light settings are defined when de App starts or come back to focus.

There’s any way to adjust some parameters from the camera?

Can I trig an autofocus every 5 seconds or something like this?

Maybe should be nice to set some “standard ISO” or exposure settings by code…

PS: Anyone knows what’s the native framerate from the iPad 4th camera?