Abstract: An infrared video camera system comprises an uncooled infrared sensor mounted and a thermally conductive thin walled radiation shield for shielding radiation from reaching an active surface of the uncooled infrared sensor. A TEC maintains the sensor active surface and the radiation shield at a substantially constant temperature. The uncooled infrared sensor and radiation shield are further housed in a hollow thermally conductive vacuum cover which is vacuum sealed with a base assembly and includes a vacuum sealed infrared transparent window in an aperture at a top end of the vacuum cover for allowing infrared radiation to reach the active surface and for forming a vacuum chamber enclosing the infrared sensor and radiation shield. A relay optical cell mounted to a camera body comprises at least one optical element for relaying an image formed at its entrance onto the active surface.