A great camera. Although superseded by later models, it can still take a fine underwater picture. There's no underwater white balance but setting it to cloudy seems to work well. Excellent shots can be had if teamed up with a decent strobe (I use the Inon Z240).
If you shoot in manual exposure mode, your internal strobe can slave trigger an old analog external strobe. There won't be any preflashing coming from the S80 while in manual exp. mode. You can even lower the internal flash output power to min so you can save your battery. I use my camera in a Ikelite housing.