Lava by Ocean
Without a doubt, one of the highlights of my time on the Big Island was the journey to the active lava flow by boat. Watching the constant battle of lava and ocean was completely awe inspiring.
From a photography perspective, the best time to take the journey is sunrise. The combination of this being the first trip of the day (so a fairly guaranteed departure time) and a predictable sunrise time, make the most optimal combination for lighting. It is 30-60 minute boat ride (depending on conditions) from the dock to the flow.
Photographing this event is a challenge. The water is open ocean, and thus not calm. You are constantly battling waves, ocean spray and toxic gases; and this is during the "calm" part of the ride close to the shore near the flow. Don't even think about pulling the camera out of your waterproof storage during the ride between the dock and the flow; you risk complete salt water annihilation of your gear. Additionally, It is nearly impossible to change a lens while at the lava flow (I foolishly attempted this, but luckily no damage was done). Oh yeah, and that doesn't take in to account that you are photographing a fast moving, bright and glowing subject (the lava), against a black dark backdrop, from a moving vessel, with unpredictable billowing steam and constantly evolving lighting conditions.
That being said, it is possible.
Most of my shots were taken with a 70-200mm f2.8 lens. I hesitated on which lens to choose, but this ended up being the right choice. While the vessel was close enough to the flow to feel the heat, smell the sulfur, and seemingly to dock on the fiery beach; the reach of the 70-200 was the perfect choice.
Enjoy! And if you have any question don't hesitate to shoot me an email.