Installed between a lens and a camera, the use of a range extender, will extend the focal length and increase the effective aperture (F/number) of a video lens. For example, using the 2XE range extender will extend the focal length by two times (2X) and double the effective aperture of the following lens:
(2X) 50 mm, F/1.3 lens = 100 mm F/2.6
Navitar also offers an extension tube kit (NMV-EXT), which allows you to turn standard fixed focal length lenses into macro lenses. This kit includes six extender tubes (0.5 mm, 1 mm, 5 mm, 10 mm, 20 mm and 40 mm) for extension from 0.5 mm to 76.5 mm. The tube(s) mount between the camera and the lens, making it possible for you to focus a C-mount lens at a much closer distance than normal.