Latham Loop

The Latham Loop is one of the most elegant solutions to a fundamental problem in film cameras: how to continuously move 35mm or 16mm film through the gate without damaging the perforations. Without this loop, catastrophic tears in the film teeth occur at higher frame rates — production stops, material is wasted. The loop creates an elastic buffer between the intermittent movement of the shutter and the continuous transport below.

Mechanically, it works like this: A deliberately formed, loose loop of film material is created before the gate. This loop is formed by two precisely positioned guide pins (Latham arms). While the shutter is closed — meaning it's stationary during exposure — these pins tension and hold the film steady. As soon as the shutter opens and the film transport sprockets become active, the pins relax again, giving the film slack. This rhythmic micro-movement reduces the immediate mechanical load on each individual perforation many times over. You can shoot at 180 fps and higher without constantly buying new film — an economic factor that was never underestimated in studios.

In practice, you work with this loop without consciously seeing it. It's adjusted before you do the initial setup. Important: The Latham Loop only functions reliably if the camera is precisely maintained. Worn sprockets or deformed arms lead to uneven tension — then material still tears. In older cameras (Arri 35 IIC, Panavision PSR), the loop is a proven design; you no longer need it for digital high-speed recording, but it still shapes the understanding of film transport mechanics to this day.

Especially when shooting with long lenses at extreme speeds — action scenes, crash shots, macro effects — you notice the difference: with a functioning Latham Loop, the film runs smoothly, the image is precisely framed, no flicker from perforation slip. This is craftsmanship solidity that you recognize again at the editing table.