The Marshall V-ZPL-1050 is a CS-mount pinhole lens manual zooming function for changing conditions or locations. With a 1/3" CCD camera the lens will display a 28° horizontal angle-of-view. At the other end of the spectrum, 50 mm will show a narrow 5.5° horizontal angle. Aperture changes with focal length. At the maximum 50 mm the lens has a f/31 aperture (f-stop=focal length/1.6) so this is not a low-light lens at zoom range. But the lens is made for tough industrial environments. A push-on front cap has two functions. It has a clear tip to protect the lens' front element. The cap also integrates a mounting support.