The SW150 Mark II fits via a lens adapter ring that has been specifically designed for that particular lens.
Each adapter consists of a front ring, a compression ring and a locking ring. When fitted, these form a collar that remains on the lens at all times.
Due to the physical size of this lens, and the extremely wide angle of view, the SW150 filter holder will vignette at the widest angles. To avoid this we recommend using a minimum focal length of 13.5mm when using the filter holder with two filter slots and 12.5mm when using the holder with one filter slot.