This Haida Drop-In Circular Polarizer Filter helps to reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface. Mounted within a geared filter ring assembly, it is made specifically to fit between a separately available Haida M10 Filter Holder and an adapter ring for the filter holder. The geared filter ring assembly's external dial allows for the independent rotation of the circular polarizer filter in order to adjust the intensity of its effect.

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 function 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.

This filter is constructed from optical glass for clarity and color fidelity. To prevent internal ghosting and reflections, each glass surface includes 10 layers of anti-reflection coatings, which also offer greater protection to the filter substrate and help keep it clean for a longer period of time. The Nano coating associated with this Haida Drop-in Circular Polarizer Filter provides an additional layer that results in an improved beading effect when the surface comes in contact with water or oil, allowing for more efficient cleaning.