A compact flat panel color calibration system includes a lens prism optic able to pass a narrow, perpendicular, and uniform cone angle of incoming light to a spectrally non-selective photodetector. The calibration system also includes a microprocessor operable to determine the luminance of the display based upon the information gathered by the photodetector. A software module included in the calibration system is then operable to process the luminance information in order to adjust the flat panel display.