LEMO

Technical Details

LEMO connectors use precision-machined gold-plated contact pins for optimal signal transmission. Standard sizes range from 00 (2.5mm outer diameter) to 3 (26mm), with size 1 (9mm) being primarily used in film technology. The connectors achieve IP68 protection class and transmit frequencies up to 3 GHz at impedances of 50Ω or 75Ω. LEMO 1B.302 (2-pin) and 1B.303 (3-pin) are the most common variants for HD-SDI and timecode transmission.

History & Development

Léon Mouttet founded LEMO SA in Switzerland in 1946 and developed the first self-latching circular connectors for the watch industry. In 1972, LEMO introduced the push-pull locking mechanism, which became an industry standard. From the 1980s onwards, LEMO connectors established themselves in professional broadcast technology, initially with Arri and later with RED, ALEXA, and other camera systems as the standard for auxiliary connections.

Practical Use in Film

ALEXA cameras use LEMO sockets for timecode synchronization, while RED systems employ LEMO connectors for monitor outputs. In "Blade Runner 2049" (2017), LEMO timecode connections enabled precise synchronization between 15 ALEXA cameras for the complex hologram sequences. Wireless follow focus systems like Preston MDR use LEMO connectors for run/stop signals. The self-latching mechanism prevents accidental disconnection during shooting, which often causes signal loss with standard BNC connectors.

Comparison & Alternatives

Unlike BNC connectors (bayonet lock), LEMOs offer higher packing density and better EMC shielding. Fischer connectors achieve similar robustness but are larger and more expensive. USB-C is increasingly displacing LEMO in consumer cameras but cannot provide the mechanical reliability for 16-hour shooting days. For critical applications, LEMO connectors remain indispensable: timecode sync requires the absolute reliability that only mechanical locking can guarantee.