Comments about Sea and Sea Sea & Sea YS-17 TTL Slave Strobe:

I am using this with a Sony Cybershot DSC-W300 with Marine Pack. Above water I shoot with a Nikon D200, but the housing plus lens ports would cost about $3000. So for $700-$800 for camera, housing, strobe, and arm I can't complain. Sad to say you are still going to have trouble getting good color if there is good sunlight getting through. I found that under the overhang of coral you will get great images. Night Dives with this were incredible. TTL stands for Thru The Lens. The built-in flash from your camera is sent to the strobe via fiber optic cable, which signals the strobe to fire. I don't quite understand how this could be considered TTL.There is also the ability to switch between 1/2 power and full power. I did find this to be useful.