I got the sony p-8 and the underwater housing for it (mpk-pha) and i was wondering was strobe to get with it. I cant spend a ton of money but the sea and sea ys-30 II TTL looked really good. Questions, comments, confessions?
You will need a "special" strobe designed to work with preflash cameras. In other words, the camera puts out a small flash before the main flash which will "trick" a normal strobe into firing early.
Check out units by Ikelite, Sea and Sea, and Inon.