Abstract: An optical apparatus for capturing digital images, and for use, for example, as a video camera includes a lens system for providing at least one derivative of an impinging light signal with respect to at least one predetermined frequency. The lens system samples the light signal as a function of the amplitude of the light signal, and rotates at an angular speed proportional to a predetermined frequency for providing a derivative of the light signal with respect to a predetermined frequency. The lens system includes three lens systems for providing three derivatives of the impinging light signal with respect to three predetermined frequencies corresponding to the three lens systems. Each of the three lens systems samples the light signal as a function of the amplitudes of the light signal relative to its predetermined frequency. In one embodiment, these predetermined frequencies correspond to the red, green and blue colors or color spectra.