How to Buy a Monocular

A monocular is a single-eye version of binoculars. The reduction of half of the structure of a binocular makes the monocular lighter and smaller than its double lensed counterpart. The monocular has many uses, from hunting and bird watching to surveillance and law enforcement purposes.

Instructions

Difficulty: Moderately Easy

1. Think about why you want a monocular. Like a free standing scope, the monocular is significantly smaller and lighter than binoculars. This means that most people who buy a monocular have size and weight in mind. Think about in what kind of environment you'll be using your monocular and what level of sophistication and clarity the instrument needs to have.
2. Consider the magnification. Magnification is one of the two or three most important optical properties of a monocular. The magnification of a monocular is indicated by the first number of the optical specification of the instrument, as in the 5 in "5 x 10." The magnification number indicates how many times larger an object appears with the monocular than with the naked eye.
3. Choose objective size. The objective size of the monocular is given by the second number in the optical specification. For example, the objective size of a monocular that is listed as "5 x 10" is 10. Objective size is the size of the front lens, given in millimeters. While increased objective size yields better optics it also makes the monocular heavier, moving it closer to binocular weight and size and away from that of a scope.
4. Test for eye relief. Eye relief is one of the most important factors to take into account when buying a monocular, especially for people who wear glasses. Eye relief is the distance from your eye that you can hold the monocular. For people in operationally sensitive situations, such as law enforcement, using a monocular that can quickly be held up a few centimeters from the eye is essential. So, find out a monocular's eye relief before you buy one.