The Horseman 90mm f/5.6 Super-Angulon XL Lens is a Schneider 90mm f/5.6 Super-Symmar XL with a standard Copal #0 shutter, but built into a Horseman-specific helical focusing mount and barrel assembly made to fit upon their SW617 Professional medium format panoramic camera. It provides an extremely wide angle perspective on the 617 Professional that's roughly equivalent to the view of a 22mm lens in 35mm terms. A built-in lens guard helps protect the sensitive optics. For critical work with transparencies, the optional Horseman #28998 center filter (B&H code "HOCF90") is highly recommended.