A monocular is a type of telescope — an optical device that magnifies distance objects using curved lenses or mirrors that gathers and focuses light or other forms of infrared radiation (in the case of digital, night vision and thermal devices) and to produce an image. Monoculars only have one eyepiece for viewing with one eye. Monoculars are more compact, lighter weight and more cost-effective than binoculars.
A (Very) Brief History of Telescoping Optics
A German-born optician named Hans Lippershey is credited with the invention of the first telescoping device. His first experiment was very simple—two lenses held together to magnify objects further away. He called it a “looker.”
In 1608, he filed a patent for his magnifier with the Dutch government but was rejected because the design of the device was too simple. His patent was published which led to many developments in the world of magnified optics.
In 1609, Galileo Galilei used Lippershey’s patent to create a high magnification telescope to view space. His had a magnification range of 3-10x. Though telescopes are mostly used for astronomy, the earliest magnified optics designed throughout the 1700s were primarily for nautical and military uses.
What Do the Numbers on a Monocular Mean?
The most important numbers in the specifications of a monocular are the magnification range and the objective lens—which are displayed like this: 8x32mm. The magnification can be either single or in a range, displayed as such: 4-16x.
The magnification (x) is the measurement of how much larger the object appears than what you see with your naked eye. As in the example above, the object is magnified 8 times. Though larger magnifications allow you to see objects much further away, it will decrease your field of view and requires a bigger optic.
The objective lens is the eyepiece located furthest away from your eye. Its diameter is measured in millimeters. The larger the objective lens, the better it gathers light, providing a brighter image. However, the quality of the lens of the monocular matters more in the clarity of the picture. Also, the larger the objective lens, the bulkier the monocular.
A larger monocular will be harder to hold steady for longer periods and more difficult to keep in focus—essentially defeating the purpose of a monocular.
Uses for Monocular
One of the greatest benefits of a monocular is the size. Monoculars are compact and lightweight. Some are even the size of a writing pen! Many monoculars will fit in your pocket and though there are compact, pocket-size binoculars, quality is (usually) significantly comprised.
Monoculars are perfect for short term scanning, scouting and viewing while:
Specialized monoculars like night vision, thermal and digital are used in law enforcement and military applications, especially when doing surveillance or searching for suspects in the dark.
There are many benefits to using a monocular vs. binoculars:
There are only a few reasons why you should pick binoculars over a monocular when it comes to your outdoor adventures — hunters and bird or wildlife watchers who must scout for long periods will feel more comfortable using binoculars.