Before going out to sea, aquarium is the best place to do homework - not for taking pictures, but identifying the marine life. The camera used is Canon EOS Rebel SL1 with 18-55mm kit lens, with Ikelite underwater housing. This setup is the lightest and smallest (and cheapest) underwater DSLR configuration. This DSLR housing is good for travel, since it's probably the only one that is small enough to be carried in backpack on the airplane. But after using it a few times, I wish I had purchased the housing for Canon 5D + 24-105mm F/4. The 18-55mm kit lens is just way too limited to handle the low light underwater environment.