The underwater cameras are almost similar to the cameras used on land. The only difference is their being waterproof. There are two types of underwater cameras, namely the housing system cameras and the amphibious cameras.
Housing system cameras are considered superior for their accuracy of composition and adaptability in most underwater situations. The features also include the variety and flexibility of the lenses. There is an SLR camera placed in the system for auto-focus and advanced exposure control. Housing systems are preferred for taking macro- shots. There are 35mm land cameras that are provided with an acrylic or aluminum watertight housing. It enables viewing through the lens more accurately and better composition control. It is generally more expensive and heavy to carry along. There are a variety of manufacturers producing underwater housings, mainly Canon and Nikon.
Amphibious Cameras are also designed to be waterproof. They work similar to other cameras. The Nikon is considered for taking wide-angle shots. Amphibious systems are small, compact and easy to transport, in comparison to housing systems. They are also called submersible viewfinder cameras. Photographers need to estimate the focus distance, since it causes difficulty in composing images. They are highly preferred by scientists, in their exploring expeditions. The cameras are designed to photograph and make available the proof and study of marine biology.