Optical Low Pass Filter (OLPF) for Blackmagic URSA Mini Pro 4.6K
Aliasing and moiré are common issues with digital imaging. To prevent it from occurring most digital cinema camera’s (including the Arri Alexa) have a built in Optical Low Pass Filter (OLPF).
The original IR absorption filter of the URSA Mini Pro 4.6K does not have an OLPF.
Blackmagic made it easy to replace it’s IR-absorption filter for an Optical Low Pass Filter (OLPF). The filter is held in place by three screws. After removing it these same screws can be used for installing the precisely fitting Rawlite OLPF.
The Rawlite UM Pro 4.6K OLPF is specifically designed for the URSA Mini Pro 4.6K, preventing moiré while preserving detail.
A hot mirror coating is added to cut Infra Red. An anti reflective coating prevents unwanted reflections.
The Rawlite UM Pro 4.6K OLPF works flawlessly together with the internal ND’s.
No more moiré, no more IR contamination.
The Rawlite OLPF is thicker than the original filter. Consequently a shim is needed to correct back focus. The shim is included in the kit, as well as tools needed for installation.
Comparison: original filter vs Rawlite OLPF URSA Mini Pro 4.6K (courtesy of Bradley J. Conomy)
Installing instructions
Instructional video – Installing replacement OLPF + IR-cut for Blackmagic URSA Mini Pro 4.6K
Instructional video – Installing the spacer underneath the contacts of the EF Mount for the URSA Mini Pro 4.6K