This WonderPana FreeArc Core Unit from FotodioX is designed to specifically fit the Sigma 20mm f/1.4 DG HSM Art lens, as well as a separately available WonderPana 6.6" Holder Bracket. Those items can be combined to 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. A compatible 145mm circular polarizer filter and a compatible 145mm solid neutral density 3.0 filter are also provided, plus a 145mm inner-pinch lens cap for 145mm FotodioX round filters.
The included WonderPana FreeArc Core Unit consists of two components, a front filter holder and a rear lens collar. Placement of this FreeArc Core Unit onto a Sigma 20mm f/1.4 DG HSM Art lens is easily accomplished by sliding the rear lens collar over the rear of the lens until it has achieved a secure fit. Afterward, the front filter holder can be screwed onto the front of the installed rear lens collar.
To use the WonderPana 6.6" Holder Bracket with the FreeArc Core Unit for a Sigma 20mm f/1.4 DG HSM Art lens, pretapped threaded inserts along the edge of the front filter holder accommodate the six included brass short screws for correct positioning of the WonderPana 6.6" Holder Bracket's two assembly pieces so that they are placed parallel to each other and can hold a 6.6" wide filter between them. Once the holder bracket and the front filter holder are combined, and the separate collar has been slid over the rear of a Sigma 20mm f/1.4 DG HSM Art lens, the front filter holder with the attached holder bracket can be screwed onto the installed rear lens collar.
After being fitted onto a Sigma 20mm f/1.4 DG HSM Art lens, the bearing design of this WonderPana FreeArc Core Unit 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.
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. Pretapped 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 is 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.
This FotodioX WonderPana FreeArc Core Unit includes front filter threads, which allow a FotodioX 145mm round filter to be used along with a WonderPana 6.6" Holder Bracket. If a 145mm round filter is used on the attached WonderPana FreeArc Core Unit, the rectangular filter slot closest to the rear of the holder bracket becomes unavailable.
FotodioX 145mm Circular Polarizer Filter
The FotodioX 145mm Circular Polarizer Filter is 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.
FotodioX Pro 145mm Ultra Slim ND 3.0 Filter (10-Stop)
Offering increased control over exposures, the Pro 145mm Ultra Slim ND 3.0 Filter from Fotodiox is a neutral density filter used to darken the entire image, thereby allowing you to increase exposure times or work with a wider aperture setting than usually required. By slowing your exposure time or increasing your aperture, you are able to control depth of field and convey movement more easily. The ND 3.0 density of this filter requires a 10-stop increase in exposure to achieve a normal exposure.
The filter is made from optical glass, which has been multi-coated to maintain image quality when working in strong lighting conditions. The glass is set in a 3mm-thick anodized aluminum ring that is lightweight, durable, and slim to help prevent vignetting when used with wide-angle lenses.
FotodioX 145mm Center-Pinch Snap-On Lens Cap for Select WonderPana Systems and Filters
The 145mm Center-Pinch Snap-On Lens Cap for Select WonderPana Systems and Filters from FotodioX is a 145mm front lens cap with a squeeze, spring, and snap-on mechanism. It is easy to install as well as remove, and can attach to a WonderPana 145, FreeArc, or Absolute filter holder system in order to protect the front element of a lens that any one of those systems are mounted on. Additionally, this lens cap can be used to protect a non-ultra slim FotodioX WonderPana 145 filter that is mounted on a FotodioX WonderPana 145, FreeArc, or Absolute filter holder system and has no other filters placed in front of it.
Lens caps protect your lens or filter from scratches, fingerprints, and the elements when the lens or filter is not in use. It's always good to have a spare in your camera bag, too.