English: The Mast Camera is a two-instrument suite of imaging systems mounted on the MSL rover's Remote Sensing Mast (RSM), with the boresight ~1.97 m above the bottom of the wheels when the rover is on a flat surface. The FFL Mastcams (we use the plural here because the “eyes” of the FFL Mastcam investigation are not identical) as built and delivered consist of two cameras with different focal lengths and different science color filters. The stereo baseline of the pair is ~24.5 cm. One camera, referred to as the Mastcam-34 (M-34), has a ~34 mm focal length, f/8 lens that illuminates a 15° square field-of-view (FOV), 1200 × 1200 pixels on the 1600 × 1200 pixel detector. The other camera, the Mastcam-100 (M-100), has a ~100 mm focal length, f/10 lens that illuminates a 5.1° square, 1200 × 1200 pixel FOV. Both cameras can focus between 2.1 m (nearest view to the surface) and infinity. The M-100 IFOV is 7.4 × 10^-5 radians, yielding 7.4 cm/pixel scale at 1 km distance and ~150 µm/pixel scale at 2 m distance. The M-34 IFOV is 2.2 × 10^-4 radians, which yields a pixel scale of 450 µm at 2 m distance and 22 cm at 1 km. A strict definition of “in focus” is used for these cameras wherein the optical blur circle is equal to or less than one pixel across. Each camera has an 8 gigabyte internal buffer that permits it to store over 5,500 raw frames. Each camera is capable of losslessly compressing the images, or applying lossy JPEG compression, in realtime during acquisition and storage, although it is more likely that images will be acquired raw and compressed just prior to downlink to Earth.