TABLE OF CONTENTS The lens data tables are quite straightforward, presenting radius, axial thickness, material name, index of refraction, Abbe V-value, and the semi-aperture (sa) for each surface. The sign convention for the radius is: positive if the center of curvature is to the right of the surface, and negative if it is to the left. A blank in the radius column indicates a plane surface (i.e., an infinite radius). The system data given with the lens table is as follows:
| EFL | = Effective focal length |
| BFL | = Back focal length |
| NA | = Numerical aperture ( f-Number) |
| GIH | = Gaussian image height (half field in degrees) |
| PTZ/F | = (Petzval radius)/EFL |
| VL | = Vertex length |
| OD | = Object distance |
The materials have been selected to match as closely as possible the materials given with the original design data. Most glasses are from the Schott catalog; close equivalents are available from other glass manufacturers. However, one should be aware that in recent years many glass types have been dropped by the glass manufacturers in favor of new formulations which are more environmentally acceptable. With a few exceptions, most of the listed glasses have current equivalents which are satisfactory substitutes. [Obviously if one is attempting to reduce or the correct secondary spectrum, one must always look beyond the six-digit (nnnvvv) glass code and check the partial dispersion as given in a "precision" melt sheet.]
