The RX100 does extremely well in low light. Most of the time you will probably be shooting at the wide angle end of the zoom range where the aperture is f/1.8, so there should be no need at all for flash at snorkeling depths. I have used several small Canon cameras in UW housings with very good results. I have tried the on camera flash on a few occasions, but it did not help much.
I have the RX100 now and hope to get a housing when the prices come down.
|Hot Air Balloons Over Bagan by User9320321874|
|Yellow Warbler by LeeS|
from A Big Year - birds
|Waiting for the Parade by tcoker1103|
from - La Vida Loca - (Black and White Street Photography+ A Border)