The Pentax 40.5mm 100 PL Polarizing Filterhelps 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 measures 40.5mm in diameter and is specifically designed for use with the Pentax Q-mount standard prime and standard zoom lenses.

Circular Polarizing Filter    Helps to Eliminate Reflections and Glare    Reduces Haze and Blue Cast in Landscapes    Greater Color and Tonal Saturation    Designed for Pentax Q Standard Lenses

Helps to reduce reflections and glare by filtering out light that has become polarized due to reflection off of 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° 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.

Related Questions and Answers

Q: 1. Will the PL-C52(WIII) or the PL-C52(WII) work/fit in the 200mm f/2L IS USM lens? Some responses from Staff state the (WII) will.

A: The W2 version is compatible with the 200mm f2 lens: https://bhpho.to/3Drway9

Q: 2. I have the Canon 300mm f2.8L IS II and the Canon 400mm f2.8L IS II lenses. Is this the correct drop-in polarizer for those *Version Two* lenses?

A: That is correct. The PL-C 52WII is the correct drop in filter for both the 300mm f/2.8 L II and the 400mm f/2.8 L Il.

Q: 3. The RF adapter with polarizing filter is $299. The polarizing filter by itself is $274 ? That's insane.

A: Yes, doesn't make sense, i'm not sure what Canon was thinking. They have their reasons for certain price points but this escapes me.

Q: 4. does the filter come with a carrying case or it just a filter in a box?

A: Yes, it comes in a case.

Q: 5. what filters fits my Pentax K-50 camera?

A: That would depend on the filter thread of the lens you are using on the K-50. Typically, you can find this on the underside of the lens cap, along the lens barrel, or inside edge of the front of the lens. It will be the number after the symbol of a circle with a line through it. If you are having troubles finding this, you could send us an email letting us know what lens you are using, and we would be able to check on this for you. a href= http://Askphoto@bhphotovideo.com target= _blank Askphoto@bhphotovideo.com/a

Q: 6. Does Canon offer a blank cover if you elect not to use the CP of ND filter?

A: Yes this is the blank drop in filter compatible with the Canon drop in EF RF adapter. https://www.bhphotovideo.com/c/product/1434115-REG/canon_3444c001_drop_in_clear_filter_a.html

Q: 7. will this filter work with the canon 6d with a 24-105L lens?

A: Yes it will. It is 100% compatible.

Q: 8. Can this filter be used with Canon RF 600mm F4?

A: Yes, the Canon Drop-In Circular Polarizing Filter PL-C 52 (WIII) is compatible with the Canon RF 600mm f/4.

Q: 9. Can this filter be used with the Canon 500mm F4 IS II?

A: The Canon Drop-In Circular Polarizing Filter PL-C 52 (WIII) is compatible only with the RF400mm F2.8 L IS USM EF 400mm f/2.8L IS III USM EF 600mm f/4L IS III USM The Canon Drop-In Circular Polarizing Filter PL-C 52 (WII) is compatible with the 500mm f/4 lens.

Q: 10. What is the difference between this (WIII) and the WII?

A: The Canon Drop-In Circular Polarizing Filter PL-C 52 (WIII) is only compatible with two lenses: EF 400mm f/2.8L IS III USM and EF 600mm f/4L IS III USM; the Canon PL-C 52WII 52mm Drop-In Circular Polarizing Filter is compatible with: EF 300mm f/2.8L IS II USM EF 400mm f/2.8L IS II USM EF 400mm f/4 DO IS II USM EF 500mm f/4L IS II USM EF 600mm f/4L IS II USM