HOYA, the world-renowned optical glass manufacturer, presents an innovative high definition line of filters. The Hoya 77mm Circular Polarising HD 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 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.
This filter is constructed from optical glass for clarity as well as colour fidelity and features a thin, aluminium-alloy filter ring that can be rotated to adjust the intensity of the polarization effect. To prevent internal ghosting and reflections, eight layers of anti-reflection multi-coatings are applied to the filter's glass. These coatings also offer greater protection to the filter substrate and help it to stay clean for longer than with uncoated filters.
The hardened optical glass that has 4 times the breaking strength in ANSI standardized testing (ANSI Z80.3: 2001) where steel balls of varying size and weight were dropped from a height of 50 inches onto the glass.
The polarizing film is the same as that used in the latest high definition LCD TV screens. It has 25% higher light transmission than the standard polarizing film used in current photographic filters.
Specialized coatings that are not just water-proof to repel water spots but also hardened to be scratch and stain-resistant. Of course, these coatings are from HOYA so they greatly reduce reflections off the surface of the glass allowing you to capture more light in your photos.
|Filter Factor||2 (1 Stop)|
|Filter Type||Circular Polarizer|
|Front Thread / Bayonet||77 mm|