How the refocusing of an image affects the structure of an axial pencil of rays

摘要

An invariable condition for the correction of aberrations of a wide pencil of rays is that the Sine condition must be obeyed, and this in general contradicts the condition that the image of an axial point of the object must remain stigmatic when the point is displaced along the optical axis from the calculated position. Expressions are obtained that determine the spherical aberration that appears in this case. (c) 2009 Optical Society of America.