Abstract: In embodiments of optical systems with at least one metalens containing at least one metasurface, the addition of the at least one metalens element is used to modify by at least ±5% either the f*tan(?) distortion, the f*? distortion or the resolution of the designed optical system compared to a reference optical system without the metalens. The method presented using at least one metalens can be used as well for monochromatic as for polychromatic optical systems. The at least one metalens element can also be used, in addition to modifying the distortion or the resolution of the optical system, to modify at the same time other optical properties like the image quality. The metalens has at least one metasurface made of nano structure elements and their shape, size, position and orientation depend on the required optical properties of the metalens.