ARRI WCU-4 Lens Control System

The Wireless Compact Unit WCU-4 combines three axes of lens control with a lens data display in a compact and ergonomic housing.

Main Features

  • Compact 3-axis lens and camera controller
  • Comfortable, ergonomic and user-friendly design
  • Integrated Lens Data Display
  • Vibrating focus marks
  • UDM-1 and Cinetape readout
  • Super-smooth, backlit focus knob with adjustable friction
  • Lens mapping to premarked focus rings
  • 3 Motors - focus, iris, zoom


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The Wireless Compact Unit WCU-4 combines three axes of lens control with a lens data display in a compact and ergonomic housing. Weighing around 780 grams including battery, it’s one of the lightest hand units in its class, providing unrivaled comfort during a long working day.

Special Features: Built-in vibration motor for tactile feedback
Focus knob: LED backlit rotary knob with adjustable friction, 3.0” diameter
16 bit native encoder resolution
Iris Slider: Fully sealed, splash- and dust-proof slider mechanism
14 bit native encoder resolution
Zoom Knob: Force sensitive knob
Ergonomic design
Display: Transflective TFT LC-Display (readable in bright sunlight)
3.0 inch diagonal
Housing: Durable and robust housing made of high-strength anodized aluminum
Sealed assembly with backlit display buttons and index marker
Mass: Approx. 780 grams including battery
Power Supply: NP-FM500H battery (Sony) or compatible batteries
BC-QM1 battery charger (Sony) or compatible chargers
Power via LCS cable through ARRI camera (cabled mode)
Operating Temperature: -20°C to +45°C

ARRI’s Wireless System is a sophisticated toolset for wirelessly controlling lens and camera functions on set.

The compact and ergonomic hand unit controls up to three lens axes for focus, iris and zoom. It includes a super-smooth focus knob with adjustable friction and backlit focus rings that are easily readable in the dark.

The WCU-4 is the first wireless control unit to use vibration markers, which provide haptic feedback for focus marks. The unit will vibrate when a focus mark is reached, allowing ACs to keep their eyes on the performers at all times and leading to greater accuracy of focus.

The large transflective display includes:

  • a lens data display (with graphical focus, iris and zoom scales);
  • camera status information;
  • & readouts from ultrasonic measurement devices (i.e. the Cinetape)

A user programmable button underneath the handle also allows rapid access to functions like quick zoom or the setting of digital focus marks.

Getting Started

Setting Up Motor Controller

First, set up the motor controller on the camera. Then power up the hand unit.

Powering Up Hand Unit

Insert a Sony NP-FM 500H Li-Ion battery or connect the hand unit via cable to power up the hand unit.

Press the POWER button momentarily. The WCU-4 screen will light up.

Connecting to motor controller

Press the MENU button and enter the Radio Channel menu. Select the same radio channel as set on the corresponding ARRI motor controller with white-coded radio modem.

Make sure that the radio transmission is switched on (upper center soft button). Return to Home screen by pressing the BACK or HOME button. The selected radio channel will be indicated in the top center area of the HOME screen. A signal strength indicator will be displayed as soon as a connection between WCU-4 and motor controller is established.

Calibrating motors

Calibrate the motor(s) by pressing the CAL soft button on the WCU-4 Home screen or on the motor controller.


Motors must be recalibrated under the following conditions:

  • When a motor is detached from the lens
  • After changing motors
  • After changing lenses
  • After a change in a motor position while powered down

Omitting motor calibration might lead to damage of the lens due to the high level of motor torque!

Using a Pre-Marked Focus Ring

The use of pre-marked focus rings on the WCU-4 hand unit requires lens data from the motor controller or camera. Press the WCU-4 MENU button. Enter the Pre-Marked Focus Rings menu and select a focus ring. Return to Home screen by pressing the BACK or HOME button. The selected focus ring will be indicated next to the numerical focus value in the center of the screen. The digital focus scale on the display will now align with the pre-marked focus ring.