Optical

Adapter for Canon EF mount lens to Blackmagic Design cameras with M43 mount, specific for BMPCC4K.
Increase maximum aperture by 1 1/3 stop. (with a maximum output aperture of f/0.80).
Makes lens 0.64x wider.
Patented 7-element/4-group optical design by Caldwell Photographic in the USA.

Electronic

Lens iris/aperture is set by the controls on the camera body.
Smooth iris support with the latest Canon (2009+), Tamron (SP series 2013+) and Sigma (2016+) lens models.
Image stabilization (IS) lens support.
Push autofocus if supported by camera.
Powered by camera body. With most lenses, no external power source required.

Mechanical

Patented positive-lock EF lens mount.
Detachable tripod foot compatible with Arca-type ball head, such as Arca Swiss, Markins and Photo Clam or attach to quick release plate by a 1/4" 20 screw.
The tripod foot is tailor-made to match the exact height as the BMPCC4K camera body.
Flocking to reduce internal reflection.
Rubber gasket protects M43 mount connection from dust and moisture.
Aluminum alloy and brass construction with chromium plating.
Satin surface finish.