Hi - recently got obsessed with snorkelling photography - max only 5 metres - main issue is buoyancy. Even with 7 Kilos on board, stop to focus, feet go first then I'm shooting to the top - attached photo shows the prob - just not sharp despite photo editing. I think for neutral bouyancy at 3 - 5 metres I'd be neg at the top wouldn't I? Any thoughts? Thanks - Errol