Immagini

DESCRIPTION

Exhibit 685 is a viewfinder for a photographic camera that permits to define the viewframe. The simplest type of viewfinder consists of a convergent back lens (eyepiece) and by a divergent front lens connected in a small telescope; thus known as a galileian viewfinder. The result is a upright image even though inverted horizontally, generally of the same dimension in which one sees with the naked eye or somewhat smaller.

This sportive view finder is a variant of the galileian viewfinder, invented by Lieuwe Evert Willem van Albada (1868-1955), an dutch officer, optical expert, and collaborator of Zeiss of Jena. The front element is semireflecting while the on the back a frame is traced that indicates the limit of the field framed by the object lens. In use the frame appears clear and superposed on the observed image. It is defined "sportive" because with this viewfinder the photographer can follow objects in movement since the image is not inverted horizontally.

ISCRIZIONI

1. sullo strumento è inciso: 5 u. 8,5
   ZEISS/IKON in un rombo
   433/25

BIBLIOGRAPHY

• [1] @ARTICLE{1924TrOS...25..249A, author = {{van Albada}, L.~E.~W.}, title = "{A wide-angle stereoscope and a wide-angle view-finder}", journal = {Transactions of the Optical Society}, year = 1924, month = may, volume = 25,

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