This WonderPana FreeArc XL Core Unit from FotodioX is designed to specifically fit the Sigma 12-24mm f/4 DG HSM Art lens, as well as a separately available WonderPana 8.0" Holder Bracket. Those items can be combined to allow for the convenient use of two 2.0mm thick filters measuring 7.9" wide, or one 2.0mm thick filter measuring 7.9" wide, along with one FotodioX 186mm round filter behind it. A compatible 186mm inner-pinch lens cap for 186mm FotodioX round filters is also provided.





The included WonderPana FreeArc XL Core Unit consists of two components, a front filter holder and a rear lens collar. Placement of this FreeArc XL Core Unit onto a Sigma 12-24mm f/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 8.0" Holder Bracket with the FreeArc XL Core Unit for a Sigma 12-24mm f/4 DG HSM Art lens, pre-tapped threaded inserts along the edge of the front filter holder accommodate six of the eight included brass short-screws for correct positioning of the WonderPana 8.0" Holder Bracket's two assembly pieces so that they are placed parallel to each other and can hold a 7.9" 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 12-24mm f/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 12-24mm f/4 DG HSM Art lens, the bearing design of this WonderPana FreeArc XL Core Unit allows a WonderPana 8.0" Holder Bracket to be rotated 360°. This permits the use of graduated neutral density and other filters that are enhanced by varied positioning.





A FotodioX WonderPana 8.0" 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 is secured by integrated guides within each slot. These guides apply pressure along both sides of a filter that is sufficient to hold it in place, but permits movement of that filter. This 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 XL Core Unit includes front filter threads, which allow a FotodioX 186mm round filter to be used along with a WonderPana 8.0" Holder Bracket. If a 186mm round filter is used on the attached WonderPana FreeArc XL Core Unit, the rectangular filter slot closest to the rear of the holder bracket becomes unavailable.





The FotodioX 186mm Center-Pinch Snap-On Lens Cap for Select WonderPana Systems and Filters is a 186mm 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 FreeArc XL filter holder system in order to protect the front element of a lens that any one of those systems is mounted on. Additionally, with the exception of the FotodioX Ultra Slim filters, this lens cap can be used to protect a FotodioX 186mm filter that is mounted on a FotodioX WonderPana FreeArc XL filter holder system.





Lens caps protect your lens or filter from scratches, fingerprints, and the elements when the lens or filter is not in use.This FotodioX Slim ND Filter features 18mm front filter threads and has a 16x filter factor that provides a 4-stop exposure reduction and is compatible with FotodioX WonderPana FreeArc XL filter holder systems. Its 1.2 optical density creates a darkening of the entire image, allowing you to photograph with a wider aperture or slower shutter speed than normally required. By slowing your exposure time or increasing your aperture, you are able to control depth of field and convey movement more easily. Neutral density filters do not affect the coloration of the image and are ideal for pairing with other filters.





This filter is constructed from optical glass for clarity as well as color fidelity and features a lightweight, slim, aluminum-alloy filter ring to minimize the potential for vignetting. A separately-available FotodioX 186mm Center-Pinch Snap-On Lens Cap can be used to protect the front of a FotodioX 186mm Slim ND 1.2 Filter that is placed in front of a lens.This FotodioX Slim ND Filter features 18mm front filter threads and has a 32x filter factor that provides a 5-stop exposure reduction and is compatible with FotodioX WonderPana FreeArc XL filter holder systems. Its 1.5 optical density creates a darkening of the entire image, allowing you to photograph with a wider aperture or slower shutter speed than normally required. By slowing your exposure time or increasing your aperture, you are able to control depth of field and convey movement more easily. Neutral density filters do not affect the coloration of the image and are ideal for pairing with other filters.





This filter is constructed from optical glass for clarity as well as color fidelity and features a lightweight, slim, aluminum-alloy filter ring to minimize the potential for vignetting. A separately-available FotodioX 186mm Center-Pinch Snap-On Lens Cap can be used to protect the front of a FotodioX 186mm Slim ND 1.5 Filter that is placed in front of a lens.The 186mm Center-Pinch Snap-On Lens Cap for Select WonderPana Systems and Filters from FotodioX is a 186mm 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 FreeArc XL 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 186mm filter mounted on a FotodioX WonderPana FreeArc XL filter holder system, with no other filter 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.