Imaging by a High Aperture Optical System

Abstract

Three-dimensional imaging in telecentric systems of non-unity magnification is considered using a scalar approximation. It is found that the imaging performance can be very different according to whether the image is formed directly in the image space or by scanning in the object space. It is shown that this result does not violate the principle of reciprocity. The point spread function is investigated for systems obeying, amongst others, either the sine or Herschel conditions. The results have great importance for scanning systems, in particular confocal microscopes, and explain some anomalies in the literature. A clarification of the principle of equivalence is given.