The URSA Mini Pro B4 Mount from Blackmagic Design is a replacement mount for use on the URSA Mini Pro.
This adapter allows you to use your URSA Mini Pro with an ENG-style B4 mounted HD lens. The attachment includes corrective optics that allow a lens built for a camera with three sensors and a prism to be used on the URSA Mini Pro, which is a single-sensor camera, without sacrificing image quality.
The lens mount has a locking lever to engage the mount's lock and accommodates lenses with a B4 lens mount. When mounting this mount on your camera, the accompanying shim kit allows for exact flange distance adjustment. The integrated optics enable HD resolution and include spherical-aberration correction, which compensates for the lens being used on a single-sensor camera when the camera is designed for a three-sensor/prism-block camera.