Chromatic correction of a Fresnel lens is effected by collecting data at multiple detectors arrayed along the optical axis of the lens and then digitally processing data from each detector to obtain multiple sets of image data corresponding to selected tuned wavelengths associated with the multiple detectors, or to obtain composite multi-color image data. Digital processing includes deconvolving data from each detector with a point spread function (PSF) associated with the tuned wavelength of the detector, and thereby enhancing the image derived from the detector. Two possible techniques are also disclosed for deriving sub-band signal data having a wavelength that falls between the tuned wavelengths of adjacent detectors.