The ARRI Rota Pola Frame helps to reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface. The light from the sun naturally becomes partially polarized due to reflecting off electrons in air molecules, causing the light to scatter into what appears as haze. A polarizing filter arranges, and filters, this directionally polarized light perpendicularly to the reflected light, allowing for the absorption of much of this light. This results in a noticeable reduction of glare and reflections from non-metallic surfaces and an increase in the saturation of skies and foliage.
A circular polarizer only differs from a linear polarizer in that it contains a quarter wave plane in addition to the linear polarizing filter. The addition of this quarter wave plane is to circularly polarize the linearly polarized light for the use of auto focus and exposure functions. Due to how the light is broken down and filtered with a linear polarizer, auto focus and exposure accuracy become skewed during use. When the light becomes circularly polarized, it permits the use of these functions.
Constructed from Water White glass for increased clarity as well as color fidelity, this filter is mounted within an aluminum-alloy filter tray for use in matte boxes that can accommodate ARRI F4 filter frames. To adjust the intensity of the polarization effect, an external dial on the filter tray allows for the independent rotation of the circular polarizer. Once the desired effect has been achieved, the filter tray's integrated lock can then be used to ensure that the position of the polarizer filter remains unchanged.