The FotodioX WonderPana 145 Core Unit Sigma 20mm Art Lensis compatible with the FotodioX WonderPana 145, FreeArc, and Absolute filter holder systems. It helps to reduce reflections as well as 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.

The FotodioX 145mm Circular Polarizer Filter is constructed from optical glass for clarity as well as color fidelity and features lightweight, aluminum-alloy filter rings. A rear filter ring connects to a compatible filter holder while four brass knobs along the side of the front filter ring allow the filter glass to be easily rotated. This provides the ability to achieve the desired degree of polarization even if another filter is placed in front of the FotodioX 145mm Circular Polarizer Filter.

For Sigma 20mm f/1.4 DG HSM Art    WonderPana 145 Core Unit    145mm Circular Polarizer Filter    1.25 to 8x Filter Factor, +0.3 to 3 Stop    Helps to Eliminate Reflections and Glare    145mm Center-Pinch Snap-On Lens Cap

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.

1.25 to 8x filter factor reduces exposure by 0.3 to 3 stops.

Constructed from optical glass for clarity.

Lightweight, aluminum-alloy filter rings along with four brass side knobs allow the filter glass to be easily rotated. The desired effect can be easily achieved even if another filter is placed directly in front.

Filter pouch included for storage and transport.

Related Questions and Answers

Q: 1. can we use LEE filter for this lens?

A: I have heard of NO firm making any add on filters for this item. Realize, it has a 94.5 degree field of view and is 85 mm! Unless you wish to make some kind of slip on thing there is nothing yet. Still, this is one of the best lenses I have gotten and I have most of the Nikon and Sigma catalogs!

Q: 2. Do I need to update this lens to work with Canon eos R5?

A: No update is needed in order to use the Sigma 20mm f1.4 lens on the Canon EF to RF adapter and the Canon R5 camera.

Q: 3. Will this work with a Nikon d800

A: Yes, the Sigma 20mm f/1.4 DG HSM Art Lens for Nikon F (B&H# SI2014N) is fully compatible with the Nikon D800 Digital SLR Camera (Body Only) (B&H# NID800).

Q: 4. Will the Nikon F version of this lens work on a Z6 with the ZTF adapter?

A: Yes, the Sigma 20mm f/1.4 DG HSM Art Lens for Nikon, would be compatible with a Nikon Z6 Camera and a Nikon FTZ II Mount Adapter.

Q: 5. will it work on a canon 50D?

A: Thank you for your interest in Sigma products. The 20mm f/1.4 DG HSM Art Lens for Canon EF is compatible with the Canon 50D.

Q: 6. Will this lense work on an SL1?

A: Yes, this lens is compatible with the Rebel SL1.

Q: 7. Will this work with live view on Sony A7R2?

A: this will work for all Sony E mount cameras, so yes the a7R II will work.

Q: 8. Are there any circumstances when removing the hood for this lens is warranted when shooting? Thanks in advance.

A: When using your camera internal pop-up flash light, the hood may black part of the flash light. Thus, it cast a black shadow on your image. If you use an external flash light, since it sit a bit higher, you may not have that issue.

Q: 9. Can this lens be fitted with circular filters or does the front element protrude too far?

A: You will want a filter holder like this one to use filters with the Sigma 20mm Art. https://bhpho.to/2Xf5Jrw

Q: 10. Is this a native L-Mount lens or does it have a built-in adapter?

A: The Sigma 20mm f/1.4 DG HSM Art Lens for Leica L, B&H # SI2014L, is designed for direct usage on the Leica L-mount lens mount. As such, no adapter is needed to connect the lens onto a camera which uses the Leica L-mount lens mount.