Lummer, O. (Otto), 1860-1925, Thompson, Silvanus P. (Silvanus Phillips), 1851-1916 · London, New York, Macmillan and Co., 1900 · leaf 79
a large angular width of field. Each member of the anastigmat inr se is only approximately achromatised ; it is a good thing, however, if the combined system is free both from “ chemical focus ” and also from chromatic differences in the size of images. The Anastigmat depicted in Eig. 1 5 is a… … Fig. 15. — Zq\s,5S, Anastigmat, Fig. 16. — Anastigmat, Series IIIg. Series Ila. lens, of course preserving opposite gradation of refractive indices in the two members. The fifth lens only serves to render possible the elimination of spherical aberration of higher orders, while employing a large…
Photographic optics
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