What Is A One Eyed Binocular Called? Find Out Here!

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October 6, 2021

Binoculars For One-Eye - Explained

There are many reasons as to why you might take preference to a one-eyed binocular rather than a two eyepieces model, for example, some prefer the lightweight and others may only have sight in one eye.

So you might be wondering, what is a one-eyed binocular called? Well, they are called a monocular which is in other words, half a binocular. 

Monocular models work pretty much the same as standard binoculars with similar features such as objective lens diameter and even focusing wheels.

We have put together a detailed monocular guide below to tell you everything you need to know about these one-eyed binoculars.

What Is a Monocular?

A monocular is a telescopic device which can help you magnify subjects from a distance. These devices use a single tube to operate and are similar to a binocular in design.

These devices are often very compact and offer a more natural way of viewing nature, making them beneficial for people who want a pocket telescope or only have sight within one eye.

How Does a Monocular Work?

A monocular works similar to binoculars and has a few different components and features within the device to help you view images clearly and from a distance.

We have listed out the key components of a monocular below for you to explore.


Just like binoculars, the magnification power of a monocular is stated in two numbers 'x' each other.

This magnification can range anything from 3x to 40x depending on the model you buy. The higher the magnification you choose on your monocular then the less stable the image will be on the other end.

You should use a stand with your monocular if your planning to get one with very high magnification over 10x.

Objective Lens

The second number next to your monocular magnification is the objective lens in mm. The larger your objective lens is in your monocular, then the higher quality image it produces with more light.

It's important to consider a larger objective lens does mean a heavier weight.

FOV (Field Of View)

The field of view on your monocular will determine the range and width of what you can see in your image.

This important for tracking moving objects so as they don't move quickly out of sight. It tends to be measured at feet per 1000 yards.

You should be aware your monocular may have a smaller field of view if you have higher magnification.

Close Focus

Some monocular models may have the option for close focus which can be useful if you are looking to view subjects within a close range with extreme detail. These could be butterflies or insects for example.

This is usually measured in inches on a monocular.

Eye Relief

Your monocular should have any eye relief of at least 15mm and over like binoculars, this allows you to use the monocular if you wear glasses and avoid your eyes getting too tired.

Night Sight

A monocular is great for using at night in comparison to binoculars and allows you to see subjects with detail thanks to their high-quality lens coatings including some features such as infrared light and an illuminator.

What Are The Benefits Of Using a Monocular?

If you are looking for a magnifying device but you are unsure with the variety on the market, there's a large list of benefits associated with using a monocular below which could help make up your mind as to which device is right for you.

  • Portable - Monocular devices are great for travelling thanks to their small size which can be easily stored away in a pocket after use and not become too heavy when carried for long periods.
  • They are affordable - Compared to telescopes and binoculars, monocular devices are very affordable as they are less expensive to build.
  • Great technology - Monocular models come with great technology now such as close focus and night vision which can help you get more out of your magnification.
  • Multi-use - A monocular can be used for a variety of different activities such as landscape detailing, hunting and even birding.
  • Durable - Most monocular devices are waterproof and shock-resistant and tend to have a shock-proof coating which allows you to drop them without the monocular lens breaking during use.
  • Helps with vision - If you have trouble with your vision, a monocular can be a nice compact way of improving it by helping you read signs and other distant objects with ease.

Monocular Vs Binocular - Which Is Right For You?

If you are looking for a portable way to magnify subjects and see further in the distance, but you are stuck between compact binoculars or a monocular?

Well, not to worry, we have got you covered with our detailed comparison between the two types of devices below.


A monocular in comparison to a binocular has many advantages. For example, these devices are very portable and pocket friendly, and they are less expensive too.

These devices additionally perform much better during the night than binoculars due to them being a single tube, as well as them being quicker to adjust into focus.

Drawbacks of a monocular in comparison to a binocular has to be its smaller field of view, the one eye tube is also more likely to have eye strain and fatigue after long periods of use.

One eye observation is also unnatural and maybe less comfortable for some users.


  • Portable.
  • Less expensive.
  • Great for night vision.
  • Quick to adjust.


  • One eye observation may uncomfortable.
  • More chance of eye fatigue.
  • A smaller field of view.


Binoculars compared to a monocular have a much better design in terms of comfort as they allow you to use both eyes for extended periods, making them easier to hold and reducing the chance of eye fatigue.

These devices also have the upper hand in terms of field of view, allowing you to have a wider range vision which is perfect for sports events.

Disadvantages of binoculars have to be there poorer night vision in comparison to a monocular and heavier weight.

The devices are also much more expensive as you are technically paying for two lenses instead of one.


  • Better comfort.
  • Wider field of view.
  • Less chance of eye fatigue.


  • Expensive.
  • Poor night vision.
  • Heavy.

Overall, if you are on a budget and want a compact magnifying device that you can use now and then to help improve your vision or spot distance objects, go for a monocular.

However, if your after the comfort factor and want to use your device for longer periods, a binocular would be a better option.

Frequently Asked Questions About Monoculars

How much does a monocular usually cost?

This depends on the magnification and strength of the model you buy, but a monocular can cost anything from £50 and above.

Higher priced models will include extras such as better night vision or a larger objective lens/higher magnification.

Can I use a monocular for birdwatching?

You can use a monocular for bird watching as it has magnification and lightweight, allowing you to use it for longer periods without getting fatigued.

Are monocular devices as durable as binoculars?

Yes, if not more as a monocular is a single tube, meaning if it gets dropped by accident there is less chance of damage to the lenses in comparison to a two-lens binocular device.

Is there such a thing as thermal monocular?

Yes, some monocular devices have night vision and thermal technology to detect subjects and movements such as animals and humans from a distance.

These monocular models however do tend to be quite expensive.

What's the best size if I'm looking for a portable monocular?

The best size to look for in your model is an objective lens of up to 30mm with a magnification of 8x or 10x, anything larger might not be a great pocket-size but should still be pretty lightweight in comparison to regular binoculars.

Born and raised in the south coast of UK, a small town close to Cornwall, I have adventure in my blood. Ever since a young age, I have always been into the great outdoors and particularly love watching the natural wildlife. Birdwatching is what I enjoy the most, and thus my natural interest in binoculars began. I founded and run Best-Binoculars.UK a site where I talk about various aspects of and review binoculars. Hope you enjoy my ramblings :)

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Born and raised in the south coast of UK, a small town close to Cornwall, I have adventure in my blood. Ever since a young age, I have always been into the great outdoors and particularly love watching the natural wildlife. Birdwatching is what I enjoy the most, and thus my natural interest in binoculars began. I founded and run Best-Binoculars.UK a site where I talk about various aspects of and review binoculars. Hope you enjoy my ramblings :)

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