Fotodiox Pro WonderPana FreeArc Essential ND1000 0.9HE Kit - Core Filter Holder, Lens Cap, 66 Brackets, 0.9 Hard Edge Grad ND & 145mm ND1000 Filters for Sigma 20mm f/1.4 DG HSM Art Lens (Full Frame 35

The WonderPana FreeArc provides the freedom to use and rotate 6.6" and 145mm 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. Additionally, standard filter sizes are not large enough to adequately cover the lens's wide angle view. The WonderPana FreeArc changes all that by providing a complete kit for mounting our collection of both round and square filters. The all-metal Core attaches directly onto the lens with a secure mounting system. With The Core in place, you can now mount any of Fotodiox's 145mm round filters. For even more filter flexibility, mount the 6.6" Filter Brackets (these mount without tools on either side of The Core). Once attached, you can easily slide in our 6.6" square filters, which are among the largest and most durable in the business. 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.PLEASE NOTE: The WonderPana Freearc you see on this page is custom engineered to fit the Sigma 20mm f/1.4 DG HSM Art Lens . It will not fit other lenses, so it's important that you chose the correct WonderPana Core system for your particular lens model. You will have to remove your lens from the camera in order to mount the filter holder. Kit inlcudes: Dedicated WonderPana FreeArc Core, WondePana 66 6.6" Filter Bracket Upgrade, 6.6"x8.5" Hard Edge Grad ND8 Filter, 145mm ND1000 filter & Heavy Duty 145mm Inner-pinch Lens Cap