1. A solid state image pickup device comprising: a semiconductor substrate; a number of pixels disposed on one surface of said semiconductor substrate along rows and columns in a matrix shape, each pixel including a photoelectric conversion element for accumulating electric charges and a color filter disposed above the photoelectric conversion element for transmitting at least one of red, green and blue light fluxes of incidence light, including pixels of a same color including two types of pixels having different spectral sensitivities; and an output signal generator for generating an output signal in accordance with charges accumulated in said number of pixels.