The optics of photography and photographic lenses (1904)
Taylor, J. Traill (John Traill), 1827-1895, Everitt, P. F · London ; New York : Whittaker & Co. · leaf 217
AN ASTIGMATIC LENSES. 205 this respect it presents a very marked difference if it be compared with the portrait construction by the same optician. The aperture of this lens is f-6, but another series has been introduced with an aperture of /-77. Messrs. Watson & Sons have also brought out an… … struction appears to be similar FIG. 84. to that of one alternative re- ferred to in the patent granted to Emil von Hoegh in 1892. This lens is called the Holostigmat. It may be pointed out, in conclusion, that the anastigmats of German origin are broadly divisible into two groups. One is…
Photographic optics · Photographic lenses
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