Hoya 77mm HRT CIR-PL UV Circular Polarising Lens Filter

The Hoya HRT CIR-PL UV Filter is designed to block ultraviolet light and reduce the bluish cast of daylight while also helping to eliminate reflections and glare by filtering out light that has become polarized due to reflection from non-metallic surfaces.

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 filter with polarizing capability 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.

This filter is non-coated and offers approximately 98% average light transmission due to its high-rate transparency polarizing film. It is constructed from optical glass and a precision milled aluminum frame.

UV Absorbing

The glass of the HOYA HRT filter also has UV absorbing properties making the HRT a combination UV/circular polarizing filter. The most common use for a circular polarizer filter is to darken bright blue skies in outdoor photography, but they also can reduce or eliminate reflections from non-metallic surfaces such as glass and water. By rotating the outer ring of the filter the change of effect can be seen by looking though the filter or through the viewfinder if it is mounted on a camera.

High-Rate Transparency Film

This filter uses a newly developed High-Rate Transparency film that passes more visible light through the filter while still filtering the same amount of polarized light. The HOYA HRT circular polarizer filter transmits as much as 25% more light through the polarizing film giving the photographer about 1/3 stop more light than a standard circular polarizer.