Lens Mount Standards — A Practical Guide for Cinematographers

A lens mount standard defines the mechanical and electrical interface between a lens and a camera body. It specifies the bayonet or screw thread geometry, the flange focal distance — the distance from the mount face to the film or sensor plane — and, for electronic mounts, the communication protocol for aperture, autofocus, and image stabilisation control.

Flange focal distance is the most critical dimension for correct focus. If an adapter changes the effective flange distance, the lens will not achieve correct infinity focus, or will only focus at close distances. Precision adapters either maintain the correct flange distance mechanically, or include an optical correction element to compensate for the difference.

Cinema mounts such as PL and LPL are designed for manual-focus cinema lenses with external follow-focus gears. Photographic mounts such as EF, E-mount, Nikon F, and MFT are designed for autofocus lenses with electronic communication. Adapting between these categories requires careful attention to flange depth and, where applicable, electronic compatibility. The Cinelux range covers the most common combinations used in professional UK production.