50-250 IR objective lens


The 50-250 athermalised IR objective lens can be switched between 50 mm and 250 mm focal lengths giving 17.5 degree and 3.5 degree fields of view. Designed for use with a range of cooled cameras including BAE Systems’ SiGMA thermal imaging camera, the lens meets military environmental spacifications. It can be used in military, paramilitary and civilian markets for surveillance and tracking applications by day and night and in poor visibility. Applications include border and perimeter fence surveillance, or mobile surveillance, mounted on tanks, remotely-controlled vehicles or in airborne and waterborne systems.

The lens has a refractive-diffractive design and operates in the 3 – 5 micron waveband with a focal ratio of F/4.0. Active athermalisation over the full operating temperature range is implemented using temperature sensors. Focus, athermalisation and field of view changes are controlled via a micro D interface link with the overall system operating from a +24V input supply. The lens is supplied with a servo-driven focus mechanism and s is housed in a rugged assembly.