The Canon HJ40X10B 2/3" EFP Telephoto Lens with Semi Servo Kit is a telephoto lens that is intended for producers and broadcasters engaged in documentary, natural history, and many other challenging location productions that seek high definition image capture over very considerable distances.The HJ40X10B offers an extremely long focal length of up to 800mm with the extender that gives you the ability to shoot from very far distances. And with the Optical Image Stabilization feature, you can capture crisp and clear images at very long distances without concern for an unsteady image. The HJ40X10B offers creative flexibility and mobility in a handheld HDTV camera system with the demanding performance requirements for high-end HDTV image acquisition at long focal lengths.Additionally the HJ40X10B incorporates a dual lens approach to broaden the shooting options, achievement of an adequate sensitivity, maximization of image contrast, and preservation of the highest MTF over the long focal ranges. Also included with the HJ40X10B is the Canon SUP-300, a support bracket for long lenses from Canon. This bracket vertically supports the long lenses for stability and to suppress lens mount damage.