On our recent Galapagos trip, we took underwater photos using a point-and-shoot Sony 5mp camera in a underwater case that is just a fancy ziplock bag ($25.00). I did not know what to expect, but was pleasently surprised by the results. These large turtles were common and it was a treat to swim alongside them. Yes, the water really was this blue. Taken just after noon on Jan. 31, 2009 off Genovesa Island.
Sony DSC-W5, ISO 100, f/2.8, 1/250, 50% crop.
I think the zop lock worked great here. Just the colors as you see them under there, great defintion, as mentioned, more room to the right, especially if you are going to print!