If you shoot primarily with wide-angle and ultra wide-angle lenses, you know how difficult it is to add filters. A lot of wide-angle lenses feature deep petal-style lenshoods and lack normal filter threads, making it impossible to add standard threaded filters. The FotodioX WonderPana uses a threaded ring and mount system which enables the attachment of 145mm round filters and square drop-in filters to several ultra wide-angle optics. Read our review
News: Digital Photography Review (dpreview.com)