ARRI WCU-4: wireless remote control unit with 7-inch touchscreen for lens control (focus, iris, zoom) up to 300 meters range.
Technical Details
The system is based on a 7-inch touchscreen with a 1920×1200 pixel resolution and offers three mechanical encoder wheels with 0.1° resolution accuracy. Battery life is up to 10 hours of continuous operation with the integrated 98 Wh lithium-ion battery. The WCU-4 communicates via the cforce protocol with compatible motors such as the cforce mini RF or cforce plus. The unit stores up to 100 lens files and supports Lens Data Archive (LDA) for automatic calibration of various lenses.
History & Development
ARRI first introduced the WCU-4 at NAB in 2016 as the successor to the WCU-3. Development aimed to integrate the proven Hi-5 Hand Unit technology into a more compact, touchscreen-based device. In 2018, ARRI expanded its functionality to include Live View streaming via Wi-Fi 6. The current software update 7.1 from 2023 integrates full ALEXA 35 support and enhanced metadata transmission.
Practical Use in Film
In "1917" (2019), the WCU-4 enabled the focus puller to make precise focus adjustments during complex Steadicam sequences over distances of up to 300 meters. The Live View function proved valuable in "The Batman" (2022) for remote monitoring in confined vehicle shots. Typical workflows include saving focus marks for dialogue scenes and synchronizing multiple WCU-4 units in multi-camera setups. The disadvantage lies in the latency of 40-60ms at maximum transmission distance.
Comparison & Alternatives
The WCU-4 directly competes with the Preston Light Ranger 2 and the Tilta Nucleus-M. Compared to the wired ARRI LCS, wireless transmission remains susceptible to interference in electromagnetically charged environments. As a successor, ARRI plans integration into the TRINITY Stabilizer System. The choice between the WCU-4 and Hi-5 depends on the complexity of the setup: WCU-4 for standardized workflows, Hi-5 for advanced programming and multichannel control.