The Dictionary Of Photography

A True Historic Record Of The Art & Practice Of Photography 100 Years Ago.

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instrument possesses a wide angle, giving splendid definition In all doublets the diaphragm being placed between the combina-tions, the distortion of the one is cured by the distortion of the other. In i860 Harrison of New York introduced his globe
Fig. 85.                                                  Fig. 86.
lens (fig. 83), which had an extremely wide angle, but which, from too close an adherence to the globe form, gave a flare. Busch improved upon this with the pantoscope (fig. 84), and Dallmeyer introduced his wide-angle rectilinear (fig. 85). Steinheil intro-
Fig. 87.
duced what he called his periscopic lens (fig. 86), which consists of two uncorrected meniscus lenses of crown glass ; and chro-matic aberration not being eliminated, the focussing screen had to be brought nearer to the lens after focussing and before exposing, by -& of the focal length of lens. Mr. Sutton's panora-
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