WonderPana 66 FreeArc Kit - Rotating 145mm Filter System Holder, 16.764 cm (6.6 ") Filter Brackets and Lens Cap for the Sigma 8-16mm f/4.5-5.6 DC HSM Ultra-Wide Zoom Lens
The WonderPana FreeArc provides the freedom to use and rotate 66 and 145 filters on your Wide and Ultra-Wide Angle Lenses. Because of the construction of these lenses, it's normally impossible to install filters as there are no filter threads, in addition standard filter sizes are not large enough to adequately cover the lens's wide angle view. The FreeArc changes all this by providing a complete kit for mounting the Fotodiox collection of both round and rectangle filters. The all-metal Core attaches directly onto the lens with a secure mounting system. The FreeArc system is a perfect fit for panorama, nature, architectural, fashion and event photographers, as well as, analog and digital filmmakers.
For even more filter flexibility, mount the WP66 square filter holders on either side of the core; once attached, 6.6" rectangle or square filters slide in easily. With the FreeArc, the filter stage is rotatable 360 degrees. The Wonderpana FreeArc can accommodate either two square filters, or one round and one square simultaneously.