The Sigma 95mm WR (Water Repellent) 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 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 auto focus and exposure functions. Due to how the light is broken down and filtered with a linear polarizer, auto focus and exposure accuracy become skewed during use. When the light becomes circularly polarized, it permits the use of these functions.

This filter is multi-coated to eliminate internal ghosting and reflections. An anti-static coating serves to limit the accumulation of static electricity, making dust particles easier to remove or preventing them from adhering to the filter. Additionally, a water-repellent coating results in an improved beading effect when in contact with water, as well as oil, for greater cleaning efficiency while enhancing scratch resistance.
Sigma WR Circular Polarizer filters are constructed from optical glass with a black rim. Set within an aluminum-alloy filter ring that can be rotated in order to adjust the intensity of the polarization effect, the glass provides increased clarity as well as color fidelity while the black rim further ensures that reflections do not occur along the filter's edge.

1.25 to 1.4x Filter Factor    +0.3 to 0.5 Stops    Helps to Eliminate Reflections and Glare    Reduces Haze in Landscapes    Greater Color and Tonal Saturation    Black-Rimmed Optical Glass, Multi-Coated    Water, Oil, Static, Scratch Resistant    Aluminum-Alloy Filter Ring    95mm Front Filter Threads    Knurled Front Edge, Plastic Case

Helps to reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface.

Polarizing filters arrange, and filter, directionally polarized light perpendicularly to the reflected light, allowing for the absorption of much of the light.

Clears up haze in distant landscapes and provides more saturated, vivid colors.

Strongest effect when used at a 90° angle from the sun.

Circular polarizers are ideal for use with digital cameras and autofocus lenses where a linear polarizer will often disrupt auto exposure and focus features.

Multi-coated to help eliminate internal ghosting and reflections.

Anti-static coating serves to limit the accumulation of static electricity, making dust particles easier to remove or preventing them from adhering to the filter.

Water repellent coating results in an improved beading effect when in contact with water, as well as oil, for greater cleaning efficiency while enhancing scratch resistance.

1.25 to 1.4x filter factor reduces exposure by 0.3 to 0.5 stops.

Constructed from clear, optical glass with a black rim which further ensures that reflections do not occur along the filter's edge.

Aluminum-alloy filter ring is durable while remaining lightweight.

Filter ring can be rotated to adjust the intensity of the polarization effect.

Knurled front edges provide a more textured grip when mounting or removing it from a lens.

95mm front filter threads allow for use with other filters.

Plastic filter case for storage and transport.

Related Questions and Answers

Q: 1. Is this compatible with the NiSi 46mm Natural Night Filter?

A: Yes, the Sigma Filter Holder with WR Circular Polarizer RCP-11 Drop-In Filter would be compatible with the NiSi 46mm Natural Night Filter.

Q: 2. Will this work with a Lee Foundation Holder or a Cokin Z-Pro holder?

A: Unfortunately no, this filter will not work. Those filter systems require square or rectangular filters.

Q: 3. why am I having problems with scratches on the glasswhy am i getting scratches on the glass?

A: A filter like a lens is still glass and is sensitive to scratches like any other lens.Some filters are better than others. But a lens cap still needs to be used when using filter to protect it when you put it in a camera bag.

Q: 4. Is the front threaded? For protective Cap Storage?

A: Yes, it has a 95mm front thread.

Q: 5. i have bought a sigma 77 mm polarized circular filter . I returned the first one after 3 days as I found small scratches on the glass and have now found considerable more scratches on the second after only three months prompting me to think that the quality of the glass or polarizing finish is not up to par . I am finicky about how and what I clean my filter with , and how I store my camera , so I know that what ever has caused the scratches can not be that significant , but maybe the glass is not as hard / strong as it should be. Can,t seem to find any specs on the grade or hardness of the glass used for these filters. Any body have any ideas ?

A: It is best if the filter comes with scratches to contact B&H customer service.Customer Service, can emailed at ord-status@a href= http://bhphotovideo.com, target= _blank bhphotovideo.com,/a or call them after 9am EST at: 800.221.5743 or 212.239.7765. Or you can talk to them in Chat.

Q: 6. how important is it for a cir polarizer filter to be multicoated?Will there be ghosting without multi coating?

A: Multi-coatings on a circular polarizer will greatly reduce the amount of ghosting and flare in a given image, however, a non-coated polarizer will not necessarily have ghosting.

Q: 7. Is there any quality degradation on 150-600mm lens, at focal lenghts beyond 200mm?

A: The Sigma 95mm WR (Water Repellent) Circular Polarizer Filter would have the same effect on the lens at all focal lengths. While adding any optic in front of the optical formula of your lens will have some amount of effect to your lens' image quality, the Sigma 95mm WR (Water Repellent) Circular Polarizer Filter is a high-quality filter, and the benefit of its circular polarizing performance in reducing glare/flare from non-metallic items, increasing contrast/saturation, and deepening the blue hue in the sky (depending on your orientation to the sun) would mitigate any minor negative degradation you would obtain from using the filter on your lens.

Q: 8. Can the included 46mm filter (glass only) in this Sigma Circular Polarizer Holder BH #SIAP2900 - MFR #AP2900 be replaced with another 46mm curcular glass polarizer?

A: No, the Sigma filter is specific to the holder.

Q: 9. Will this fit the sigma 150-600 lens?

A: Yes, it will.

Q: 10. What is the widest focal length (in full frame) without vignetting?

A: The Tilta 95mm Circular Polarizer for Mirage Matte Box can support 24mm without vignetting on full frame.