AUTOMATIC STEREO SHUTTER
Wollensak Optical Company, Rochester, New York 1903-1909
Automatic Stereo Shutter, manufactured by Wollensak Optical Company for the Gundlach-Manhattan Optical Company, Rochester, New York.
Although this shutter can be encountered on any number of stereo cameras from the early 1900's, it will typically be found on Gundlach-Manhattan's stereo cameras from about 1903 to 1909, based upon the shutter's construction. Various models of these cameras were produced under the "Korona Stereo", "Stereo Koronas" and "Series VII Korona Stereo" names to cite a few.
The shutter, a stereo Wollensak Automatic that was badged "Gundlach- Manhattan Optical Co." was the top-of-the-line shutter offered as an option with these cameras. The shutter required only one action on the part of the operator to cock and fire it. The Automatic Stereo Shutter was priced about 22% higher than Wollensak's Regular Shutter, which required the operator to manually cock the shutter before releasing it. The Automatic Stereo Shutter appears to have never been offered as a stand-alone item in the Gundlach-Manhattan catalogues that I've had access to.
By 1903, although Gundlach-Manhattan continued to offer a few of their own shutters, they were also offering Bausch & Lomb's Volute along with the introduction of four shutters manufactured by Wollensak that carried the Gundlach-Manhattan name.
While Wollensak's Stereo Regular is rather scarce, the Automatic Stereo having been their premium and more costly shutter is almost never seen today.