A method and apparatus involve using optics to direct radiation from a scene along an optical axis, the optics having a chromatic dispersion that is a function of a characteristic spectral signature for the scene so as to produce a chromatic blur that, for an extended depth-of-field region, is substantially spatially constant along the optical axis. A different method involves: identifying for a characteristic scene a spectral response curve; determining a plurality of different wavelength nodes dividing the area under the spectral response curve into a plurality of substantially equal segments; generating a mapping relationship that maps each of the wavelength nodes to a respective one of a plurality of focal points spaced substantially equally along the optical axis; and configuring the optical system as a function of the mapping relationship.