In 1952, during the golden era of 3D film, Bolex offered the Bolex Stereo: a 3D stereo kit for their H16 camera and model G projectors. Several technical changes were made to the H cameras in 1954, above all an entirely different claw drive together with a laterally inverted film gate and a 170 degrees opening angle shutter. In 1956, the first H16 reflex viewfinder model was brought out. In reaction to the upcoming use of heavier varifocal or zoom lenses and the bigger synchronous electric motors attached to the body Paillard gave it a big rectangular base, with three tapped bushings replacing the original single-tap “button” base in 1963 and soon afterward a protruding 1-to-1 shaft for the ESM motor. A saddle for a 400-ft. film magazine finally allowed the H 16 to be used like professional synch-sound cameras.