Buy the S6 System (150mm) – filters for extreme wide angle
Ultra wide lenses with a bulbous front element and a fixed petal hood simply cannot take a normal filter holder – they need a large format system built around them. This holder mounts to the lens barrel through a lens specific adapter and carries rectangular filters far enough out that the corners of your frame stay clean and free of shading. The integrated polariser still rotates on its own. That means graduated and ND filters finally work on lenses that were otherwise shut out of filtering entirely. Buy the S6 System now.