Ursa Minor (cave) Ursa Minor (cave) Ursa Minor Cave is part of Sequoia National Park, a naturally formed system of caves in California's Sierra Nevada. The cave was discovered in August 2006 by four cave explorers from the Cave Research Foundation who found a softball-sized hole on a cliff face in the mountains. After widening the hole to allow for human entry, the explorers discovered one of the most spectacular caves in the western United States. The cave has since been named "Ursa Minor," because of the large bear skeleton found in the cave. The cave was featured in the September 2007 issue
Blackmagic URSA as the URSA Mini Pro. The camera features a 4K sensor, 2/3" style B4 lens mount, traditional external controls (like on the Mini Pro), built in optical ND filters, and dual CFast and dual SD card recorders. While the Broadcast ships with a B4 sensor, the camera is compatible with EF, PL and F mounts, sold separately by Blackmagic. The Blackmagic URSA Viewfinder is a viewfinder made by Blackmagic Design. It comprises a 1080p OLED screen and can be focused and adjusted to both the left and right eye and only turns on by a proximity sensor dubbed the "Eye-sensor".