Optical aberration

Summary

An optical aberration is a departure of the rays of a real optical system from the ideal image predicted by the paraxial approximation. With aberrations, the rays from one object point do not meet again in one image point, and the image is blurred or deformed. Aberrations are measured either by the displacement of rays in the image plane or by the deviation of the wavefront from a sphere. Their analysis and correction are the core of lens design in geometrical optics.