The techniques involved in using photographic equipment underwater. Underwater photography is used to document subjects in fresh-water lakes and quarries, in temperate seas, beneath the polar ice pack, and in the deep sea, but by far the greatest percentage of underwater photography is done within sport-diving limits in the tropical oceans. The color and variety of marine life in the Caribbean Sea, Red Sea, or Indo-Pacific Ocean are diverse and compelling, creating an ever-changing portfolio of subjects to photograph.