An extended depth of field (EDOF) imaging system that has a corresponding extended depth of focus (EDOF′). The imaging system has an optical system consisting of a single lens element and an objectwise aperture stop arrange substantially at a zero-coma axial position. The single lens element is configured so that the optical system has a select amount of spherical aberration (SA) in the range 0.2λ≦SA≦2λ, where λ is an imaging wavelength. The single lens element generates an amount of axial chromatic aberration that increases the EDOF while decreasing the average MTF of the optical system relative to the optical system having no chromatic aberration. The imaging system has an image sensor for forming a digitized raw image of an object.