This Tiffen 138mm Circular Polariser Filter is designed for use within the Tiffen Multi Rota Tray. It helps to reduce reflections and glare by filtering out light that has become polarised due to reflection from a non-metallic surface. The light from the sun naturally becomes partially polarised due to reflecting off electrons in air molecules, causing the light to scatter into what appears as haze. A polarising filter arranges and filters this directionally polarised 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 polariser only differs from a linear polariser in that it contains a quarter wave plane in addition to the linear polarising filter. The addition of this quarter wave plane is to circularly polarise the linearly polarised light for the use of auto focus and exposure functions. Due to how the light is broken down and filtered with a linear polariser, auto focus and exposure accuracy become skewed during use. When the light becomes circularly polarised, it permits the use of these functions.

This filter is non-coated and is constructed from Water White glass for clarity as well as colour fidelity, and features an aluminium-alloy filter ring for durability while remaining lightweight. To adjust the intensity of the polarisation effect when used with the Tiffen Multi Rota Tray, an external dial on the tray allows for the independent rotation of this circular polariser.