Tack-Sharp Focus Tracking for Dynamic Camera Movements

The ARRI Ultrasonic Distance Measure UDM-1 is an indispensable focus-assist tool designed to take the guesswork out of pulling focus on fast-moving sets. By calculating the exact flight time of bounced ultrasonic pulses, the UDM-1 accurately measures the distance between the camera's sensor plane and the subject. This instant, reliable feedback gives focus pullers and 1st ACs the telemetry they need to confidently keep subjects pin-sharp, even when shooting wide open on long cine prime lenses.

Smart Range Filtering Eliminates False Readings

On complex sets filled with moving props, crew members, and background activity, typical distance measuring devices can easily get confused. The UDM-1 solves this issue with its highly adjustable display interface, which lets the camera assistant establish strict minimum and maximum measuring boundaries. By filtering out foreground clutter or deep background objects, the sensor concentrates solely on the active tracking zone, sending clean, reliable data directly to the camera rig.

Seamless Integration with the ARRI Electronic Control System

The UDM-1 is engineered to link directly into your existing ARRI workflow. When connected to platforms like the ALEXA 35, ALEXA Mini/LF (via an LCUBE CUB-1), or the Radio Interface Adapter RIA-1, the measured distance is transmitted wirelessly to the Hi-5 or WCU-4 hand unit. When paired with active motor controllers or the UMC-4, the system can execute continuous, automatic focus tracking—adjusting the lens motor in real time to match the subject's physical position.

Built for Demanding Production Environments

Designed to withstand the daily wear of high-end feature film and commercial sets, the UDM-1 kit consists of a rugged dual-horn sensor module and a compact display controller. Its bright transflective screen remains perfectly visible under direct summer sunlight, while its standard cabling options make it simple to mount, calibrate, and deploy. Whether you are running a lightweight stabilizer rig or a massive studio build, the UDM-1 provides the ultimate safety net for flawless focus performance.