The Calypso-Phot was the first self-contained 35mm camera designed specifically for underwater use. Conceived by Jacques Cousteau and designed by Belgian engineer Jean de Wouters, it was introduced in 1961 and built to operate at depths of up to 200 feet (60 meters) without an external housing. The camera featured a rugged, watertight body with O-ring seals, a bayonet-mount lens system, and a simple combined wind-on and shutter release lever, making it easy to handle underwater. It supported lenses from manufacturers like SOM Berthiot and Angénieux, including 28mm, 35mm, and 45mm primes.