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 200
PHOTOGRAPHY 170 Some good modern doublets are the Zeiss ^ ^'Tes- sar/’ Goerz ® ''Dagor/’ Cooke ® Anastigmat, Voightlander ‘‘Heliar/’ Harris ® ''Euryplan/' 108. Telephoto Lens. — There is yet one lens which requires some mention. It is the telephoto combination. The purpose is to enlarge the size of… … by simply increasing the focal length of the lens, which moreover leads to clumsy apparatus and requires a very steady support. The idea of the telephoto lens will be best obtained from the dia- gram, Fig. 45. It consists of the usual high class lens of the converging type, and at some distance…
Photography
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