Auto Iris Direct Drive 4mm Lens

An Auto Iris Direct Drive lens. This lens type relies on the camera having a built in electronic amplifier to control the opening and closing of the lens iris. This means that Direct Drive lenses are usually cheaper than Video Drive lens which have this circuit duplicated in the lens. If a camera can use either lens type, Video Drive (VD) or Direct Drive (DD or DC Iris), then it makes sense to use the Direct Drive lens as it saves money and does an equally good job as the Video Drive.