The Heliopan 40.5mm 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. This results in a noticeable increase in the saturation of skies and foliage, as well as clearer imagery when photographing in hazy conditions. A linear polarizer differs from a circular polarizer in that it does not supports use of a camera's autofocus or auto exposure functions; it is 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 front and rear surfaces of the filter both feature a single anti-reflection coating. Each coating helps to increase light transmission by reducing reflections, scattered light, and ghosting. Additionally, they offer protection to the filter substrate while helping to keep the glass clean for longer than uncoated glass.
This Heliopan filter is constructed from Schott glass for increased optical clarity and color fidelity. It features a brass filter ring for durability as well as jamming prevention.