This 4-pin to 12-pin Hirose adaptor cable will power your B4 lenses allowing use of the zoom servo rocker switch.
Designed specifically for the Sony F5 and F55 cameras, this takes power from the cameras output.
Also this enables the start/stop button of the lens to trigger the camera.
Must be used with the Sony F5 or F55, or a compatible 4-pin Hirose power source.