The ARRI EF Mount (LBUS) allows the ALEXA Mini LF or ALEXA Mini to accept lenses with an EF mount and it also provides an LBUS connector.

In order to extend the benefits of using EF mount lenses to large-format motion picture productions, ARRI has redesigned its EF mount with 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.

The use of cine-style EF mount lenses on motion picture cameras has been a popular way to make more affordable optics available to budget-conscious productions. Their mechanical focus rings with physical end stops and industry-standard gears allow the use of external lens motors and precise remote control through ARRI ECS hand units like the wireless WCU‑4 and SXU-1 and the wired Operator Control Unit OCU‑1 and Master Grips. Setup of external lens motors is fast and clean with the LBUS connector on the lens mount, which frees up the EXT connector on the Mini LF and Mini. With the use of the ARRI Lens Data Archive, metadata from the external lens motors will be displayed as well as recorded. 

Additionally, the ARRI EF Mount (LBUS) allows filmmakers to utilize the wide variety of still photo EF mount lenses for insert shots, including vintage lenses, extreme wide-angle lenses, fisheye lenses, tilt-shift lenses, extreme telephoto lenses, macro lenses and other specialist EF mount lenses. For specialty shots, the ARRI EF Mount (LBUS) even powers the image stabilization built into some telephoto EF mount lenses. Since most still photo EF mount lenses have internal iris motors, those can be set by the camera and ARRI ECS hand units.  

Built to ARRI’s exceptionally high standards of durability and reliability, the ARRI EF Mount (LBUS) is suitable for hard-wearing use on professional film sets.