An IR camera comprises an IR Focal Plane Array having a number of detector elements as sensor devices, an optical system focusing an object onto the Focal Plane Array, and a signal processing system connected to the Focal Plane Array. The camera also has a modular structure comprising a camera housing provided with the Focal Plane Array and the signal processing system, an absorbent/emitting shielding device connected to the camera housing, and an optical focusing system removably mounted to the shielding device.