. This 5-element viewfinder covers a maximum viewing angle of 105 degree. Optional interchangeable finder masks match it to different focal length lenses. This is the Horseman 21511 Optical Viewfinder ONLY for SW-612 Cameras. Masks not included. Horseman SW612D accepts a bright viewfinder that allows easier framing. Also it becomes compatible with all lenses by simply changing viewfinder masks. There is a circular 'peephole' through which the distance scale on the lens barrel (except for the 35mm lens) and the horizontal spirit level are visible. This lets you keep your eye pressed to the viewfinder while maintaining proper level and distance setting.