Ray had this to say about his equipment and techniques:

I have done 35 mm underwater photography almost since I was certified, but
was never very good at it. When I finally flooded my Nikonos V in the
Cayman Islands I decided to try video. I enjoyed shooting video underwater
a lot more, and have never looked back."

I currently use a Sony TRV900 camcorder housed in a Light and Motion
Bluefin housing. My lights are the Light & Motion Elites, which have halogen bulbs. Though the Bluefin is not without its problems, when it's functioning correctly there isn't a better system to work with; probably the best feature of this model is the optics, which are excellent, particularly the Super Zoom Macro that I used for many of the shots in Down and Dirty. My backup housing is a Gates Diego for the TRV900, which is also excellent and very reliable. After being spoiled by ergonomics of the Bluefin's electronic controls, though, it's hard to go back to using the totally manual Gates. But it's always reassuring to know that the trusty Diego is in the stable.

Having said this, I must admit that I'm now moving to a Sea & Sea VX-2000 Pro housing with a Sony PD150 camcorder. I like having the greater mass of a big, heavy
housing - this makes it easier to get steady shots. When you're shooting video, inertia is your friend. And the PD150, big brother to the VX2000, uses the DVCAM tape format, which has several advantages over MiniDV.

People, even some non-photographers, often ask how I keep the tiniest subjects so steady while shooting. Well, there is no great secret to this - you just have to keep the camera still! In the muck, I usually just jam the housing down into the mud (though this tends to stir up the silt). In trickier situations I use four pounds of lead shot in a bag to rest the housing on, much like a land photographer uses a beanbag. In some situations I use a tripod or even a handy rock pile. Breath holding while shooting doesn't seem to work for me - I find that keeping a loose grip on the handles works better. Ultimately, though, it's concentration that keeps the camera steady. During the critical seconds of a shot, you have to believe that nothing else in the world matters except keeping that camera still! It's amazing how much pain you can put up with when you're getting some unique footage.

Another "secret" has to do with subject matter. These days it's not enough just to have a rare or exotic subject - you also have to catch it doing something interesting.
Often this means spending an entire dive (or more!) on one critter, waiting for the right moment, sometimes with the camera running the whole time. It's much better in the long run, I think, to come back with a few excellent sequences than with a whole pile of mediocre ones, and patience usually pays off in spades.

The TRV900 is an amazing camera in light of its relatively low cost. Its color reproduction is superb, and it generates the sharpest images of just about any camcorder (some say that it is actually TOO sharp). The auto-focus is magical - the 
lens has an almost supernatural ability to discern exactly what is the subject of interest, and to stay in focus even when the subject moves. In low contrast situations I set it to manual focus to avoid hunting. The TRV900's output is considered broadcast quality, and mechanically it is an extremely rugged and reliable piece of gear. Like any CCD device, though, it is easily fooled by the "unnatural" color balance found underwater, so I carry a small white slate and set white balance manually to the slate."