An image sensor including a planar sensor array, a lens configured to form an optical image on the planar sensor array and characterized by a locus of focal points on a curved surface, and a cover glass with multiple thickness levels or multiple cover glasses of different sizes. The one or more cover glasses are configured to shift the locus of focal points for large field angles, such that there are multiple intersections between the planar sensor array and the locus of focal points for a large FOV, and thus multiple zones with best focus on the planar sensor array.