THE KORONA STEREO
Gundlach-Manhattan Optical Company, Rochester, New York 1903
Introduced by the Gundlach Optical Company in 1900 as the Korona Stereoscopic, and later manufactured by Gundlach-Manhattan Optical Company, the 5x7 Korona Stereo would be offered for at least twenty-one years from 1900-1920.
In 1900, it was only equipped with the Korona D Stereo Shutter, and several lens options were offered. But by 1903, it could be had with no less than four stereo shutter options. Available were the Korona Junior Stereo, Korona Winner Stereo, Korona Automatic Stereo and the Korona D Stereo as shown on this example. In 1912, four stereo models were available: the higher-end Stereo Korona Series III, IV or V, and the Series VII Stereo Korona, an economy version. By 1915, only the Series VII Stereo Korona remained, being built through at least 1920. I haven't determined whether production continued beyond then, but by 1922, Gundlach-Manhattan no longer offered stereo cameras or stereo shutters. By this time, stereo photography's popularity was well past its prime and wouldn't experience a resurgence until the 1950's.
This example dates to approximately 1903, based upon the camera's construction, the Korona D Stereo Shutter's known production run, and the style of the retardant valve's lower end which is now reflected as being flat instead of nipple-shaped in the factory catalogue engraving. These Korona D Shutters (mono versions of the Korona D Stereo Shutter) illustrate this difference:
Korona D Shutter with nipple end Korona D Shutter with flat end
Korona Stereo cameras are not encountered very often, and this is the only example I've ever seen equipped with the Korona D Stereo Shutter. It's also the only example of a Korona D Stereo Shutter that I'm aware of. As stereo shutters go, it can be considered very rare.