ABSTRACT
The notions of a thin lens and of combinations of thin lenses are essential in setting out optical systems on the basis of their Gaussian properties, conjugate positions, pupil positions, magnification, relative aperture, and so on. Equally the thin lens concept is useful in the early stages of aberrational design that is where the approximate powers, bendings and positions of lens elements are being determined for the required aberration correction. The thin lens aberration formulae also lead to several useful general rules about the kinds of correction possible in certain cases. Many different sets of variables for thin lens theory have been used, some unsymmetrical and others symmetrical and more or less resembling the original Coddington variables. Thin lens aberration formulae for a remote pupil are, of course, essential for design work involving off-axis aberrations. The chapter shows how thin lens theory can be used by means of a number of examples.
