The FotodioX WonderPana FreeArc Kit for Sigma 20mm Art Lensis a two-piece assembly designed to be used in combination with a FotodioX WonderPana FreeArc Core Unit, a WonderPana 145 Core Unit, or a WonderPana FreeArc Aluminum Step-Up Ring. A WonderPana Core Unit or a WonderPana FreeArc Aluminum Step-Up Ring with the WonderPana 6.6" Holder Bracket attached can then allow for the convenient use of two 2.5 to 4.0mm-thick filters measuring 6.6" wide, or one 2.5 to 4.0mm-thick filter measuring 6.6" wide along with one FotodioX 145mm round filter behind it.

Use of this holder bracket is easily accomplished by separately attaching its two assembly pieces to opposite sides of a WonderPana Core Unit or a WonderPana FreeArc Aluminum Step-Up Ring using the six included brass short-screws. Pre-tapped threaded inserts along the edge of a WonderPana Core Unit or FreeArc Aluminum Step-Up Ring accommodate those screws and ensure correct positioning of the two assembly pieces so that they are positioned parallel to each other and can hold a 6.6"-wide filter between them. The combined WonderPana Core Unit, or WonderPana FreeArc Aluminum Step-Up Ring, and WonderPana 6.6" Holder Bracket can then be attached to a compatible lens.

For WonderPana Core Units that consist of a rear lens collar and a front filter holder, pre-tapped threaded inserts along the edge of the front filter holder accommodate the six brass short-screws for correct positioning of the WonderPana 6.6" Holder Bracket's two assembly pieces. Once the holder bracket and a front filter holder are combined, and the separate collar has been slid over the rear of a compatible lens until it has achieved a secure fit, the front filter holder with the attached holder bracket can be screwed onto the front of the installed rear lens collar.

After being fitted onto a compatible lens, the bearing design of the WonderPana FreeArc Core Units and WonderPana FreeArc Aluminum Step-Up Rings allows a WonderPana 6.6" Holder Bracket to be rotated 360°. This permits the use of graduated neutral density and other filters that are enhanced by varied positioning. While a WonderPana 145 Core Unit does not include a 360° rotating mechanism, eight pre-tapped threaded inserts all around its edge allows the WonderPana 6.6" Holder Bracket to be installed in 45° increments so that rectangular filters placed within it can be angled to the best approximate position relative to the subject in front of the camera.

The FotodioX WonderPana 6.6" Holder Bracket provides two pairs of filter slots, a configuration that accommodates two compatible rectangular filters. For each rectangular filter that is placed within one of the holder bracket's slots, its position can be secured using the included brass long-screws. Pre-tapped threaded inserts along the outside of the holder bracket allow the long-screws to each apply pressure to a spring-loaded retainer within each filter slot. When a pair of the long-screws are used, the level of grip upon a rectangular filter can be varied, which can complement the use of graduated filters whose effect can be adjusted to better suit changing lighting conditions or creative demands by sliding them up or down within a filter slot.

Each FotodioX WonderPana Core Unit or WonderPana FreeArc Aluminum Step-Up Ring includes front filter threads, which allow a FotodioX 145mm round filter to be used along with this filter holder. If a 145mm round filter is used on the attached WonderPana Core Unit or WonderPana FreeArc Aluminum Step-Up Ring, the rectangular filter slot closest to the rear of the holder bracket becomes unavailable. The WonderPana 6.6" Holder Bracket features a lightweight, aluminum-alloy construction that has a corrosion-resistant, black anodized finish for durability. A rigid pouch is included for storage and transport.

For Sigma 20mm f/1.4 DG HSM Art    WonderPana FreeArc Core Unit, Lens Cap    WonderPana 6.6" Holder Bracket    6.6 x 8.5" Graduated ND 0.9 Filter    Hard-Edged Line of Transition    Up to 8x Filter Factor, 3-Stop    Reduce Exposure in Selective Areas    145mm Circular Polarizer Filter    1.25 to 8x Filter Factor, +0.3 to 3-Stop    Helps to Eliminate Reflections and Glare

• When used with a FotodioX WonderPana FreeArc Core Unit, a WonderPana 145 Core Unit, or a WonderPana FreeArc Aluminum Step-Up Ring, allows for the convenient use of two filters measuring 6.6" wide, or one filter measuring 6.6" wide along with one FotodioX 145mm round filter installed on a Core Unit or FreeArc Aluminum Step-Up Ring
• Provides two pairs of filter slots, a configuration that accommodates up to two 2.5 to 4.0mm-thick rectangular filters
• Allows up to two compatible rectangular filters to be rotated 360° when used with a FotodioX WonderPana FreeArc Core Unit or WonderPana FreeArc Aluminum Step-Up Ring
• When used with a WonderPana 145 Core Unit, allows up to two compatible rectangular filters to be installed in 45° increments so that a filter placed within it can be angled to the best approximate position relative to the subject in front of the camera
• Ability to vary grip on each installed rectangular filter to complement the use of graduated filters whose effect can be adjusted to better suit changing lighting conditions or creative demands by sliding them up or down within a filter slot
• Lightweight, aluminum-alloy construction with a corrosion-resistant, black anodized finish for durability
• Rigid pouch included for storage and transport

Related Questions and Answers

Q: 1. Can this be used with sony a7r iva directly without an adaptor?

A: Yes, the Sony A7R IVA will accept the Sigma 20mm f/1.4 DG HSM Art Lens for Sony E directly without the need of an adapter.

Q: 2. Since front holder and rear collar when assembled block hood petal cutouts of 11-24mm lens, how bad is the vignetting?

A: The FotodioX WonderPana FreeArc XL Core Unit Kit for Canon 11-24mm Lens with 186mm Slim Circular Polarizer Filter will not vignette when mounted to the Canon 11-24mm Lens.

Q: 3. Will this fit the Sigma 14-24 DG N sony e Mount?

A: Yes, if it is the Sigma DG DN Art lens.

Q: 4. I need to use a clear or haze filter. Is it possible to utilize more than one filter at a time-a polarizer and an ND filter?

A: You cannot stack a uv filter on top of the Slim Circular Polarizer Filter included with the FotodioX WonderPana FreeArc XL Core Unit Kit for Sigma 14-24mm Art Lens with 186mm Slim Circular Polarizer Filter. Fotodiox 186mm filters are not designed with a front threads.

Q: 5. Will this work on the new Sigma 12-24 Art?

A: It works well with the 11-24 canon so I can only assume that it will work with that lens. n Needs to be kept spotlessly clean so as to avoid flare abboration

Q: 6. What ND Filter can be used on this lens? I would be using it on a Sony A7S II.

A: I don't believe you can use an ND filter on this lens, but I don't know for sure.

Q: 7. Any way to block lens flares with some sort of hood?

A: The 186mm Slim Circular Polarizer included with this kit does not have front threads, nor is there a hood to fit.

Q: 8. Can this lensbe made to work Can this lens be made to work with a Canon DSLR? If not, any plans to make one for a Canon DSLR?

A: No, the Sigma 20mm f/1.4 DG DN Art Lens for Sony E will not work on a Canon DSLR. The Sigma 20mm f/1.4 DG HSM Art Lens for Canon EF will work on Canon DSLR cameras. B&H # SI2014C

Q: 9. I am looking close at this lens because of the fast aperture. I shoot exclusively at night and wondering if anyone knows if this lens has coma?

A: Every lens has coma/ comatic aberration.DXOMARK rates it at this link and you can compare it with other lenses. But as lenses go it is a very good lens for low coma compared to other lenses, http://bit.ly/2ay1IWA.

Q: 10. Does it have linear acceleration response MF?

A: Yes, Sigma 20mm f/1.4 DG DN Art Lens for Sony E has the same linear accelatation when the lens is set to manual focus.