The science and practice of photography : an elementary textbook on the scientific theory and a laboratory manual (1920)
Roebuck, John R. (John Ransom), 1876-1965 · New York ; London : D. Appleton and company · leaf 191
LENSES i6i lens, modifies the distortion greatly. In case the distortion is barrel-shaped, as in Fig. 36 (a), a dia- phragm in front of the lens exaggerates it greatly, while pin cushion distortion, Fig. 36 (b), is exag- gerated by the diaphragm behind the lens. The size as well as the shape of the… … The obvious remedy is to use two lenses placed on opposite sides of the diaphragm so that their dis- tortions will be of opposite kinds, and so neutralize each other. Largely on this account most photo- graphic lenses are of this doublet pattern. The rapid rectilinear is the commonest lens of this…
Photography
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
