1. An optical system for providing an image of a scene, the optical system comprising: (1) a first lens that is operative for imaging the scene at an image field, the first lens comprising; (a) a first lens element that is a sphere having a center at a first position, the first lens element comprising; (i) a first hemisphere having a first surface whose center of curvature is located at the first position; and (ii) a second hemisphere having a second surface whose center of curvature is located at the first position; wherein the first lens element imparts a first aberration with a first magnitude on light that transits the first lens element, the first aberration being one of spherical and chromatic aberration; (b) an entry lens shell having a uniform thickness and a center of curvature at the first position; and (c) an exit lens shell having a uniform thickness and a center of curvature at the first position; wherein the first lens element interposes the entry lens shell and exit lens shell, and wherein the first lens element, the entry lens shell, and the exit lens shell collectively impart the first aberration with a second magnitude on light that propagates through the first lens, and wherein the second magnitude is less than the first magnitude; and (2) a plurality of cameras, each camera comprising a second lens and a sensor array, the second lens being operative for (1) reducing the magnitude of the first aberration and (2) relaying a portion of the image field to form an optical sub-image at the sensor array, and the second lens and sensor array collectively defining a unique optical axis for their respective camera.