The Schneider Optics 68-013127 Circular True-Pol Rotating Filter (5"/127 mm) is designed for cameras which use polarizing elements in the beam-splitters of the viewing system, such as ARRI 435 and the Movie-Cam compact lenses. This filter can also be used on certain high-definition video cameras with complex optical blocks such as the Sony PMW-EX1, PMW-EX3, and PDW-700 cameras which polarize the red and blue channels more than other cameras and therefore require a circular polarizer to prevent cross polarization and associated color shift in the image.
The filter has beam splitters that send light in 2 directions one to an eye-piece and other to a video tap. The light in a camera’s viewing system can become polarized, and when a standard (linear) polarizing filter is attached to the lens, the light becomes cross polarized. This hinders visibility and may create total black-out of the viewing image and/or the video tap.
The filter has a circular polarizer that features a 2-layer design to prevent this blackout. The first layer is made up of the same polarizing material used in all true-pol filters, and the second layer is a 1/4-wave retarder plate, which effectively prevents cross-polarization.
