"Martha's Vineyard was also chosen because the surrounding ocean had a sandy bottom that never dropped below for out from shore, which allowed the mechanical sharks to operate while also beyond sight of land.As Spielberg wanted to film the aquatic sequences relatively close-up to resemble what people see while swimming, cinematographer Bill Butler devised new equipment to facilitate marine and underwater shooting, including a rig to keep the camera stable regardless of tide and a sealed submersible camera box.