How do Monoculars Work?

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Monoculars are the simplest of all the optical devices, as they consist of one lens, a tube, and an eyepiece. In fact, it is a specific kind of telescope, which is relatively smaller in size than its other variants. It comes with a converging lens, which helps to magnify the objects that cannot be seen clearly by the naked eye.

The best thing about monoculars is their lightweight and compact design. This makes them the preferable option to birdwatchers, golfers, and hunters. If you are wondering how monoculars work, here is a comprehensive explanation.


To put it simply, a monocular makes it possible to view a distant object by magnifying it. When light passes through the lenses of a monocular, it magnifies the image or object. As a result, the image of an object located at a distance appears to be quite clear and closer. 

Magnification is the power of a lens to enlarge an image. Additional magnification power is suitable for a better view, yet it makes the optical instrument hard to use. This happens in most of the lightweight and small devices such as monoculars. 

Usually, 5x or even 6x magnification power is excellent for a small monocular. It is much easier to focus on the object and get a wider field of view. On the other hand, a lens with an 8x magnification power will be a bit harder to control. The image produced is less steady, and the field of view will also be narrower.

Talking about the principle of light refraction, prism lenses act differently when compared to conventional optical lenses. Therefore, these lenses affect your vision and sight differently. In fact, a prism has a pointed top, and its base is similar to a pyramid. 

As the light passes through the prism, it bends towards the base. The object usually shifts to the pointed top. Therefore, the visible object appears to be moving in that particular direction. A similar mechanism applies to the working of a variety of telescopes. 

When used in various orientations and with different magnification powers, a prism lens affects the direction of our view. This is the reason we see a single image rather than two.

How do Monoculars Work

Lens Size 

A monocular is relatively a lightweight optical device when compared to binoculars. Although the materials used may be similar, there is a noticeable difference concerning the weight of both these devices. 

So what makes monoculars lightweight? The answer relates to the number of lenses used. Binoculars use double the number of lenses than monoculars. Additionally, the lens size is different, which adds more weight to the binoculars. 

Lens size also affects the field of view. It is an overall area, which you see through an optical device. For instance, if you are looking at ten birds sitting on a branch, the limited field of view will allow you to see only a few of them when viewing through a monocular. 

The field of view becomes shorter as we use lenses with more substantial magnification power. Moreover, the objective size relates to the size of the front lens, which affects the optical performance of a monocular. The bigger the objective lens, the more focused and clear the image you get. 

Usually, monoculars come with a lens size that starts from 20mm and goes up to 42mm. Different size lenses offer variable magnification power. If you don’t have any issue with the weight of a monocular, it would be better to go for the large lenses because it will help you to overcome the issue of limited view. 

A monocular with a 30mm to 42mm lens would serve its purpose well in most cases. On the other hand, if you are one of the weight-conscious backpackers who have concerns over the slightest increase in the luggage weight, a monocular with a small lens is a good option. However, with this type of monocular, you may have to compromise the overall image quality and field of view.

Usability Factor 

Speaking of the usability of a monocular, this type of device proves to be handy in various circumstances. For instance, you can use it for sightseeing or locating a target. Hunters use monoculars with either their rifle or with other hunting equipment. Besides, these devices work perfectly well while using them single-handedly.

A monocular captures the distant image and magnifies it. You can use it in various circumstances such as military activities, sightseeing, hunting, birdwatching, golfing, and mountaineering. When you want to explore the outdoors, you require a monocular with higher magnification and better resolution.


No doubt, monoculars are perfectly designed and thoughtfully engineered devices. They work well in different situations, where others fail to perform. Although each of these optical devices has its own benefits and disadvantages, using them with reference to a particular situation can offer a much better outcome. Now that you know how monoculars work, you can make a decision on what size will work best for you.

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