Opera Binoculars, with a single lens, were first invented in 1730 and used in Theatre’s to allow audience members to see the performance in more detail. However, these were not like the ones we know these days. It was not until 1823 in Vienna, that the first twin lens binocular opera glasses were invented and put into use.
As a close cousin to a pair of regular binoculars, opera glasses are likewise a magnification tool to bring the faraway nearer and so, typically, opera binoculars, also sometimes referred to as opera or theater glasses, regularly provide a magnification factor around 3 times, very occasionally creeping up to 4 times magnification. however that is usually adequate to see the action on a stage whilst retaining a bright enough image and a wide field of view.
Opera Binoculars are built of two cylinders connected with a bridge piece. Each eye-tube extended independently for focusing. Pierre Lemiere (from Paris) improved on these, and created the center focus wheel, which allowed the focusing of both eyes together. The making of fine opera glasses required knowledge not only in optics. Each glass was worked on by painters, goldsmiths and other artists. By the second half of the 19th century they had become essential fashion accessories for theatre- goers. Many opera glasses were given as gifts and tributes, as can be seen by the inscriptions found on many of them.
While the original Opera Binoculars/glasses were made of metal and glass twentieth century theatre glasses were usually of cheap plastic. Whilst playgoers could buy their own it was more usual to hire them from a dispensing unit on the back of the seat in front.