When I was in Oahu a few weeks ago I was shooting a bit of photography like this. Super close to the water as it splashes up against the sand or surrounding rocks. It's actually not the smartest thing to do with an expensive Sony A7r and after a few very close encounters I decided it was enough. But not before I got a few cool shots!
I did actually ended up with a grain of sand in one of the little wheels that took me a few days to finally grind out.
I've been seriously considering getting one of the Nauticam under water housings for my camera for this type of stuff and more snorkeling and underwater stuff.
What would really be cool is you could use a Sony A7, A7r and A7s all in the same case. So with one case you could have an awesome low light camera or a great landscape camera. . . if you can afford it.
Splash – Oahu Wave Photo
To get a shot like this you really have to get right up close to the water, just a few inches from the incoming splash. The faster the shutter the better. I've done this stype of photography a lot in Southern California but everything just turns out better in Hawaii for obvious reason. It's risky if you have valuable gear, but fun.