Larry
Nice part of video is you don't need light, the camera picks up all the light you need. I only use lights on night dives. Doing swim thru on wrecks or small cave/corral swim thrus the camera pick up great, What I see with my eyes is what comes out on the film. But the monitors or Mirror set ups that you see in the lense looks black. When I can see clearly and the monitor looks black, I thought it doesn't work, but when you play black on a tv or put on your computer you can see in dark areas, just not in total black areas like filming in a hole. Just go out and shoot.
Biggest thing I try and do is hold the camrea still which I'm not good at. I did just start to add a couple pounds of weight to see if that keeps me from moving some. I still experminting with that. I did it on a shark feed to help me stay on the bottom and that seems to worked.
Another thing I do is on every dive trip, My first dive is a dry run on the camera housing without the camera. I like to pressure check it before giving it a big workout.
Like I said this is my first video but I've been shooting it for two years. I just not any good a video editing to put anything together.