In that era, we mostly used 16mm Arris or Bolex cameras in custom housings. Beyond 300 feet, we had to re-pressurize the housings underwater with a connector like an inflator. Then release the added pressure before ascending again… a bit complicated but pretty functional. We used lenses behind dome ports that gave us as much as 145 degree fields of coverage. In the clear water at depth, sometimes 150 feet horizontal, this allowed us to capture nearly half of the fast attack sub’s profile as they zoomed past. Our primary subject matter was anything that gave off a wake vortex (props, struts, diving planes, rudder, etc.) and so we concentrated on that stuff. Very exciting.