The Speed Booster ULTRA 0.71x Adapter for Nikon F Lens to BMPCC 4K Camera from Metabones allows full-frame Nikon F-mount and G series lenses to be mounted onto a Blackmagic Design Pocket Cinema Camera 4K MFT-mount camera. While doing so, the adapter's optics help to maximize the connected lens's apparent angle of view while providing a 1-stop increase for the camera over the lens's aperture range. The adapter provides manual aperture control.

If a lens intended for 35mm film or similarly-sized full-frame camera sensors is connected to a camera with a Micro Four Thirds sized sensor, it would project an image larger than the Micro Four Thirds sensor was built to accept. Able to capture only the centre portion of the projected image, the effective angle of view of the lens would be narrowed, creating an in-camera crop factor. The Speed Booster 0.71x adapter condenses the light from a lens designed for 35mm film or "full-frame" camera sensors and projects it onto a Micro Four Thirds sensor. This allows the Blackmagic Pocket Cinema Camera 4K with a Micro Four Thirds sensor to utilize more of the light gathered by a connected lens, which effectively reduces the crop factor while making available to the sensor an additional 1-stop of light for each of the lens's f-stop settings.

This adapter is constructed from aluminium for durability while minimizing weight, and its mounting rings are made with brass to further prevent wear and tear. The internal lens elements are designed to provide optical clarity as well as colour fidelity, and a detachable tripod foot is included and features 1/4"-20 threads as well as compatibility with Arca-Swiss tripod heads.