Systems and methods include imaging optics having one or more optical elements for modifying a wavefront of electromagnetic energy incident thereon. The wavefront, modified by the optical elements, exhibits a non-monotonic wavefront phase profile. The imaging optics are characterized by a modulation transfer function that is substantially invariant over a range of misfocus. The system optionally includes a detector for receiving the electromagnetic energy from the imaging optics. A method of maintaining modulation transfer invariance over a range of misfocus in an optical imaging system includes modifying a wavefront of electromagnetic energy incident to the optical imaging system such that the wavefront exhibits a non-monotonic wavefront phase profile and a substantially invariant modulation transfer function over the range of misfocus.