ARRI's new Zoom Main Unit ZMU-4 offers improved connectivity and control

ARRI’s new Zoom Main Unit ZMU-4 is a modern version of the classic and ubiquitous zoom control enabling clutter-free camera builds and faster on-set workflows.

With the launch of the Hi-5 hand unit, ARRI introduced the fifth generation of its Electronic Control System (ECS). Now, the company’s ZMU-4 joins that new ecosystem, sharing the Hi-5’s swappable RF-EMIP, RF-2400, and upcoming RF-900 radio modules, with different frequencies for different territories and shooting situations. Whichever radio module is chosen, it fits neatly into a recessed slot in the ZMU-4 and becomes integral to the slimline form factor. All of which means there are no external radio boxes and no additional cables or setting up — users can just unplug from the camera and go.

It's a handy and flexible unit. In its most basic configuration, the ZMU-4 can control cforce motors via the LBUS connector without any wireless capability. The CAM connector opens the door to run/stop, camera control, and user button activation for ARRI and third-party cameras. Slot a radio module into the ZMU-4 and it becomes a powerful tool for transmitting and receiving radio signals from multiple ECS devices. That means that DPs and camera operators can jump from a dolly or tripod to a remote monitor station and still use the same muscle memory on the same tools.

When used as a radio receiver, the ZMU-4 performs the same role as the Radio Interface Adapter RIA-1, removing the need for an extra box on the camera body. It can enhance the flexibility of existing ECS motor controllers with support for the ultra-long-range RF-900 and RF-2400 radio modules, or it can replace motor controllers entirely. Conveniently located on the pan bar, the ZMU-4 performs these duties and enables multiple camera user button functions for operators, even when not using a zoom lens.

As a motor controller, the ZMU-4 allows any camera and lens from any manufacturer to benefit from the features of the ARRI Hi-5 or WCU-4 hand units, without the need for additional motor controller boxes. Again, this makes for a cleaner camera build.

As well as expanding the wireless functionality on-camera, the ZMU-4 can also be paired with devices such as the ARRI OCU-1 or Master Grips to offer multi-axis control off-camera. The combination of ZMU-4 and OCU-1 could be used as a small, handheld or monitor-mounted zoom and iris control unit for a DP, for instance. The flexibility and strength of the LBUS protocol and ARRI’s user buttons and Lens Data System offer a myriad of possibilities for camera and lens control. In the future, the ZMU-4 will be able to control fourth and fifth-axis motor channels within the Hi-5 ecosystem.

The unit is ergonomically designed for ease of use by both left and right-handed operators. The force-sensitive zoom knob allows precise control, and the display screen shows the exact focal length at any point in the zoom range, as well as the zoom speed. Three user buttons offer customizable shortcuts for the operator and dedicated zoom speed buttons fall neatly under the index finger. In keeping with all ARRI equipment, durability was a design priority, with the result that the ZMU-4 is the most rugged and weather-resistant unit on the market. It provides future-proof connectivity and versatility, while also being backwards-compatible with all existing ARRI ECS equipment.

And like the Hi-5, the ZMU-4 is compatible with industry-standard Sony NP-F550/570 batteries ( though it has been designed and optimized to make use of proprietary ARRI LBP-3500 batteries, which offer more consistent power delivery and an unprecedented run time of at least 15 hours with the RF-EMIP radio module). The ARRI batteries also allow the ZMU-4 to display remaining power as a highly accurate percentage, permitting more efficient battery management than is possible with any other zoom control.

The ARRI ZMU-4 is available to order now. Pricing starts at €3750 for the basic unit and just over €5000 for something with a radio module that is usable out of the box.