No sooner was the telescope invented in than the early 1600s than did astronomers get the idea of mounting two of them together, effectively inventing the first binoculars. Galileo (who is often falsely credited with having invented binoculars) adapted an earlier design, using optics that combined convex and concave lenses to create a magnifying effect just like that used today in the cheapest nonprismatic glasses marketed for sports or theater viewing, or for use by children.
In the mid-1850s, Ignazio Porro of Italy patented a design using two prisms constructed in a Z shape to present the viewer with an image that not only is better magnified, but has depth. The Porro prism design was followed a few decades later by the roof prism, in which the prisms are constructed in one unit.
Soon, binoculars were adapted for military use, and were employed during the Civil War.
Quality made a big jump around the turn of the 19th century, and continued to be refined in the early 1900s.
With the advent of World War II, more manufacturers entered the binoculars market, including, in the United States, Bausch & Lomb. Germany continued with its production of highly regarded binoculars, with a few changes. For example, Zeiss, one of the top names in binoculars, experienced a confusing shift, with a new factory established in East Germany under Russian control with the Zeiss name while another factory named Zeiss was began exporting from West Germany, according to a history in the 1961 book Binoculars and Scopes and Their Uses in Photography, by Robert J. and Elsa Reichert.
Japan exports binoculars via various manufacturers, and some U.S. companies import Japanese-made binoculars but sell them under the U.S. company name.
