Arri 16ST Film gate
In Arri 16ST, the film advance pin (left) is engaged from the back of the film. There are two pins that are involved: One pin advances the film while the shutter swings closed , and the other engages with the film perforation while the shutter swings open to prevent film from moving during each exposure. The Film advance mechanism in Arri 16ST, and SRII are made with extreme precision to insure film steadiness during each exposure. Arri claims it could keep the film as steady as 1/400 of the film aperture's height.
Holding the 16 ST you are actually holding the housing for its disc shutter. It's a very unique design.
Requires Timing Alignment