NiSi 138mm Mounted Linear Polarizer Filter

The NiSi 138mm Mounted Linear Polarizer Filter 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 linear polarizer differs from a circular polarizer in that it does not contain an additional quarter wave plane. The addition of a quarter wave plane is to circularly polarize linearly polarized light for the use of autofocus and exposure functions. Due to how the light is broken down and filtered with a linear polarizer, in-camera autofocus and exposure accuracy become skewed during use. When the light becomes circularly polarized, it permits the use of these functions.

This filter is recommended when not using in-camera exposure metering or autofocus. It is non-coated, constructed from water white glass for optical clarity as well as color fidelity, is 138mm in diameter, and is mounted for use in third-party or custom filter holders. No front or rear threads are included on this filter's ring or mount.