The Heliopan Bay 70 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 only differs from a circular polarizer in that it does not contain a quarter wave plane that enables use of auto focus and exposure features. Linear polarizers are best suited for use with manual cameras, such as view cameras, that are not dependent on internal mechanisms to determine focus or metering settings. The filter ring is constructed out of matte black brass, which provides durability and further prevention from glare. They also feature high quality Schott glass for greater optical clarity and color fidelity. The Bay 70 mount is compatible with the Hasselblad-specific bayonet lens mount.