With the introduction of true day/night cameras, CCTV cameras have become more versatile - and now lenses must match the wide range of light conditions covered by those cameras. (Infrared) corrected lenses provide fully adjusted and sharp focused images in daylight and at nigh when used in conjunction with IR illuminators. This makes IR lenses the best choice for high performance true day/night cameras. The IR range includes 1/3" and 1/2" format lenses. The Bosch 1/3" lenses are used exclusively for 1/3" type cameras. The high design standards of the 1/2" lenses make them a perfect match for both 1/3" and 1/2" type cameras. When used with 1/3" type cameras, the 1/2" lenses provide a more "telephoto" effect. For auto iris control, all lenses use the standard four-pin EIAJ connector, which fits directly into the camera's iris output. Varifocal lenses are DC iris direct drives, while zoom lenses have Video-iris drives. For zoom focus and pre-position control, the lenses are fitted with an 8-pin DIN connector. The 18x zoom lens also features manual iris override. Impressive optical quality is a result of ED glass elements, aspherical lenses, and multilayer coatings. These lenses maintain focus to IR wavelengths of 950 nm.