ARRI EF Mount with LBUS

ARRI EF Mount with LBUS for ALEXA Mini and Mini LF

More than 130 million EF lenses are out in the world from Canon, along with countless others from SIGMA, Tokina, Tamron, ZEISS, Fujinon, Samyang and others.

Wouldn’t you want to try some of these on your ARRI ALEXA Mini or ALEXA Mini LF camera?

Now you can, with the new ARRI EF Mount (LBUS) for large-format and Super 35 lenses. Yes, there was an earlier ARRI EF Mount, but it did not have an LBUS electronic connector and it vignetted certain Full Frame lenses.

New ARRI EF Mount (LBUS)

The new ARRI EF Mount (LBUS) has:

  • a wider light baffle that doesn’t vignette,
  • an extra LBUS connector that frees up the EXT connector on the camera,
  • focal length and iris lens metadata that are sent to the camera.

Marc Shipman-Mueller, ARRI Product Manager Camera Systems, explains, “The use of Canon EF mount lenses on motion picture cameras has been a popular way to make a wider range of more affordable high-quality optics available to budget-conscious productions. It also allows filmmakers to use interesting EF mount lenses.

“Since the EF mount was originally designed to cover full-frame 35 mm stills, the lenses are equally useful for large-format and Super 35 cinematography.”

Some of the special EF mounted lenses that Marc mentions are vintage, modern and glass of unusual distinction. They include wide zooms, macros, tilt-shifts, fast long lenses and products with built-in optical image stabilization (IS or OS).

It can be a lot cheaper to use these lenses as-is with their native EF mounts than subject them to a lens conversion.


A partial list of interesting Canon EF lenses might include:

  • EF 100mm f/2.8L Macro IS (Image Stabilized)
  • EF 180mm f/3.5L Macro
  • EF 8-15mm f/4L Fisheye
  • EF 11-24mm f/4L
  • EF 16-35mm f/2.8L III
  • EF 85mm f/1.4L IS (Image Stabilized)
  • EF 70-200mm f/2.8L IS II (Image Stabilized)
  • EF 28-300mm f/3.5-5.6L IS (Image Stabilized)
  • EF 100-400mm f/4.5-5.6L IS II
  • EF 200mm f/2L IS
  • EF 300mm f/2.8L IS II
  • EF 400mm f/2.8L IS III
  • EF 600mm f/4L IS III
  • EF 800mm f/5.6L IS
  • TS-E 17mm f/4L Tilt-Shift
  • TS-E 45mm f/2.8 Tilt Shift
  • TS-E 50mm f/2.8L MACRO Tilt-Shift
  • TS-E 90mm f/2.8L MACRO Tilt-Shift
  • TS-E 135mm f/4L MACRO Tilt-Shift

A few of the more than 40 SIGMA lenses in EF Mount:

  • 14-24mm F2.8 DG HSM | Art
  • 24-70mm F2.8 DG OS HSM | Art, Optical Stabilizer
  • 105mm F2.8 EX DG OS HSM Macro
  • 200-500mm F2.8 APO EX DG
  • 150-600mm F5-6.3 DG OS HSM | S

Marc continues, “In order to extend the benefits of using EF mount lenses for large-format productions, ARRI has redesigned the existing EF Lens Mount. The new one has a wider light baffle, allowing it to cover the large-format sensor of the ALEXA Mini LF, as well as the Super 35 sensor of the ALEXA Mini. In addition, an extra LBUS connector frees up the EXT connector on the camera. The previous ARRI EF Lens Mount will remain available for the ARRI AMIRA camera, which does not support LBUS.

Earlier ARRI EF Mount for ARRI AMIRA (no LBUS connector)

Remote control of EF mount lenses

Marc Shipman-Mueller explains, “As with the old EF Mount (no LBUS), the new EF Mount (LBUS) allows internal motors of EF mount lenses (focus, iris and zoom) to be controlled by the ARRI WCU-4 or SXU-1 wireless hand units, Operator Control Unit OCU-1 and Master Grips.

“Focus pulling will work best with the OCU-1 or Master Grips since their control rings, like most EF mount lens focus rings, do not have fixed end stops. This is also why only focal length and iris metadata (not focus) are available from those lenses; the lens simply does not know its absolute focus setting.

“Also new is the ability to use an external cforce motor without an external radio receiver. With the old EF lens mount, camera assistants had to use the AMC-1 (Active Motor Controller), UMC-4 (Universal Motor Controller) or cforce mini RF motor. Now the LBUS cable of the cforce motor plugs directly into the LBUS connector of the EF Mount (LBUS) and the camera’s radio is used to communicate with the WCU-4 or SXU-1. The advantage of ditching the external receiver is a smaller and simpler set up.

“In addition, lens metadata now goes into the camera, where it can be displayed via SDI outputs and in the viewfinder as well as recorded into the image file.

“To use the cforce mini RF motor, which is the fastest and most responsive motor, switch the motor to “client” mode and connect it with an LBUS cable to the EF Mount (LBUS).

“Note that when the focus of the EF mount lens is switched to AF (Auto Focus) and a cforce motor is connected, the EF lens’s internal focus motor has priority. To give priority to the cforce motor, switch the EF lens to MF (Manual Focus).”

All these remote control options work with ALEXA Mini LF as well as with ALEXA Mini.
The EF Mount (LBUS) joins the list of lens mounts for ALEXA Mini LF and Mini from ARRI and third parties: LPL, PV, PV70, PL-to-LP adapter, Leica M and XLP52. The EF Mount (LBUS) is available in April 2020.


Summary of Lenses and Mounts for Large Format ARRI ALEXA LF and Mini LF




This article first appeared in FDTimes April 2020 Issue 101.

Leave a Comment

Tags: , , , ,