Relative magnification and aspect ratio
It is well-known that the magnification of an imaging lens changes with the object distance (distance from the object to the lens). However it is less known that the magnification changes with the field angle as well (i.e, where in the field the object is placed). Additionally the off-axis magnification can be asymmetric. In other words, the tangential and sagittal magnifications can be different. This causes shape deformation for off-axis objects. For example, a golf…