ARRI B4 mount adapter for large sensor cameras

Compatible with C300 up to RED EPIC, ARRI AMIRA and ARRI Alexa.

Broadcast lenses are available in high zoom ratios with wide apertures in a relatively compact size, making them a desired option for many large-sensor camera users. Designed and built by ARRI, The B4 adapter provides an interface between a B4-mount 2/3” lens and a large sensor camera, expanding the projected light to cover the image area.  Note that there are optics inside this adapter to resize the image and as a consequence there is approximately a 2 stop loss.

The ARRI B4 adapter increase the focal length of the attached video lens so that the expected field-of-view of the lens is maintained on the larger format sensor. The depth of field of the image will be closer to that of the larger format.

The ARRI B4 adapter expands a B4-mount lens image by approximately 2.2 times, covering:

Vision Research Phantom:
Flex, v642, v641, v341 (up to 1920×1080)
Miro LC320S, M320S, M120

Panasonic:
AF100

RED:
Scarlet, Epic, One (up to 3K 16×9)

Blackmagic Design:
Cinema Camera

Effective aperture is lowered by approximately two stops.

VMI has tested the following cameras with the ARRI B4 adapter

ARRI AMIRA