A color image sensor includes a pixel array including a CFA overlaying an array of photo-sensors for acquiring a color image. The CFA includes first color filter elements of a first color overlaying a first group of the photo-sensors, second color filter elements of a second color overlaying a second group of the photo-sensors, and a plurality of filter stacks overlaying a third group of the photo-sensors. The first group generates first color signals of a first color channel and the second group generates second color signals of a second color channel. Each of the filter stacks includes a first stacked filter of the first color and a second stacked filter of the second color. A sensitivity of the filter stacks equals a product of sensitivities of the first and the second stacked filters and the filter stacks generate a third color channel.