This is the optional manual zoom control for Th16x5.5BRMU/Th13x3.5BRMU lens for GY-HD100 series. This unit can be attached onto the handle of GY-HD100 and connected to the zoom connector on the above lens. Zoom speed can be switched two steps by the degree of strength of pressing the control lever with slight adjustment mechanism.
Slow or fast zooming can be selected by the depth of the lever pressed manually. (Deep: Fast/Shallow: Slow) The speed of the slow zooming is preset (internal adjustment.)