I have just bought this waterproof housing and camera (Mark III) and have not yet had the opportunity to use it. However, after a dry run, I have already noticed that the side knob cannot drive the rotating ring around the lens (configurable alternative) and the side button for activating the lens.However, after a dry run, I have already noticed that the side knob does not drive the rotating ring around the lens (configurable alternative) and the side flash button does not work either (may require a small adjustment which I have not yet tried). Otherwise, all the other buttons are usable (top wheels, zoom, power, etc...). Personally, I intend to use it like this and make this purchase worthwhile as the Mark 2 is outdated.
I hope this answers the question.