binoculars
Binoculars field glasses or binocular telescopes are a pair of identical or mirror-symmetrical telescopes mounted side-by-side and aligned to point accurately in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. binoculars give users a three-dimensional image: for nearer objects the two views, presented to each of the viewer's eyes from slightly different viewpoints, produce a merged view with an impression of depth.
Types
Galilean binoculars
Opera glasses, also known as theater binoculars, are compact, low-power optical magnification devices, usually used at performance events, whose name is derived from traditional use at opera performances. Magnification power below 5× is usually desired in these circumstances in order to minimize image shake and maintain a large enough field of view. A magnification of 3× is normally recommended. The design of many modern opera glasses of the ornamental variety is based on the popular lorgnettes of the 19th century.
Prism binoculars use image-erecting prisms to provide correctly oriented images. Without prisms, the image would always appear upside down and reversed.
Porro Prism Binoculars
Porro prism models will deliver good optics for the dollar, but lack the durability and compact styling of roof prism models. In addition, many Porros are not waterproof.
Reverse Porro Prism Binoculars
This design allows for a compact binocular that easily fits in your hand.
Roof Prism Binoculars
In recent years, the popularity of the roof prism design has increased dramatically. These binoculars are rugged and durable, and you no longer have to spend more money to get good optical quality in this design.
Types
Galilean binoculars
Opera glasses, also known as theater binoculars, are compact, low-power optical magnification devices, usually used at performance events, whose name is derived from traditional use at opera performances. Magnification power below 5× is usually desired in these circumstances in order to minimize image shake and maintain a large enough field of view. A magnification of 3× is normally recommended. The design of many modern opera glasses of the ornamental variety is based on the popular lorgnettes of the 19th century.
Prism binoculars use image-erecting prisms to provide correctly oriented images. Without prisms, the image would always appear upside down and reversed.
Porro Prism Binoculars
Porro prism models will deliver good optics for the dollar, but lack the durability and compact styling of roof prism models. In addition, many Porros are not waterproof.
Reverse Porro Prism Binoculars
This design allows for a compact binocular that easily fits in your hand.
Roof Prism Binoculars
In recent years, the popularity of the roof prism design has increased dramatically. These binoculars are rugged and durable, and you no longer have to spend more money to get good optical quality in this design.