I was able to try out some underwater photography during a few snorkeling stops in the Caribbean this year. The above image is of a sea turtle during a stop in Barbados.
I used a DiaPack Underwater Case to protect my camera when shooting. I also used my old Rebel XTI just in case there was an issue. I used the case on four different spots, all with great success. I would defiantly recommend using this waterproof bag. The only draw back is that you pretty much have to set your camera to no flash auto and take what you get. You can use the view finder to frame your shots though, but that is about it.
Sometimes when shooting I didn’t bother to try and frame anything, I just pointed the camera in the direction of something that looked cool, and fired away. This approached seemed to work well for my first time trying this type of photography.
It was very fun to shoot underwater. Not sure when I will have the opportunity to do it again.