ESTIMATING SECONDARY COLOR

Image quality of a refracting lens system often will be limited by res idual secondary color. Information in this paper permits rapid determi nation of blur spot size, and resulting image quality degradation, due to secondary color for a refracting lens system that has been designe d with normal optical glasses and is free of primary color (achromatic ). Included here is a brief description of the basic theory involved a nd an example of how the plotted data are used.