BreakThrough X4 Circular Polarizer Filter - 77mm

The Breakthrough Photography 77mm X4 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. 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 a 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 addition of this quarter wave plane is to circularly polarize the 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, autofocus and exposure accuracy become skewed during use. When the light becomes circularly polarized, it permits the use of these functions.

To prevent internal ghosting and reflections while providing 99.7% polarizing efficiency and 47% light transmission, each glass surface includes four layers of anti-reflection coating. This Multi-Resistant Coating (MRC) also offers greater protection to the filter substrate and helps it to stay clean for longer than with uncoated filters. The Nano coating associated with X2 circular polarizing filters provides an additional fifth layer over each MRC, resulting in an improved beading effect when in contact with water for greater cleaning efficiency.

This Breakthrough Photography circular polarizer filter is constructed from Asahi glass for increased optical clarity as well as color fidelity and features thin, aluminum-alloy filter rings to minimize the potential for vignetting.