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Monoculars | Uses, Comparison With Binoculars & Reasons To Get One

Last Updated: 12.08.22

Monoculars are becoming more and more popular nowadays among wildlife enthusiasts, birdwatchers, hunters, sports fans, and other people who want to benefit from a small optical device that can bring objects in close view. These little devices are versatile and can offer great viewing experiences in a variety of conditions.

There are also lots of shapes, sizes, and optical configurations to choose from so you can definitely get a model that perfectly suits your needs as well as budget.

Enrich your outdoor adventures

Whether you’re a hardcore hiker or just like to go out and camp somewhere in the middle of the wilderness from time to time, getting a quality monocular can help you see more of your surroundings.

These small devices come in various optical configurations so that you can pick a model with high magnification powers for a closer look at wildlife species, or a monocular with a wider field of view to see mountains in all their splendor. You can also use one of these to orient yourself depending on natural landmarks and check what lies ahead of you on the nature trail.


Study your favorite bird species

While many birdwatchers use binoculars to spot and study birds, monoculars are quite a good choice as well. These are lighter than their double counterparts and are easier to use. You can keep a monocular in your shirt pocket and use it as soon as you see some movement. You don’t need to have both hands free, which is a pretty good advantage for spontaneous observations.

You can choose a model with a moderate magnification of 8x for normal study, or use a magnification of 10x or higher to see birds in finer details. Just make sure that you also get a tripod if you intend to use a more powerful monocular.


Never miss the action

One great way to enjoy your favorite ballgame is to take a monocular with you at the stadium. Even if you didn’t have enough money to buy one of the better seats that are closer to the action, you could still watch everything in high detail from afar.

You can watch your favorite football players as they try to score a touchdown, or take the monocular to a sailing competition and admire the view.


Spot wildlife during the night

Whether you prefer hunting under the cover of the night or just enjoy nocturnal animal observations, then a good night vision monocular can help you spot wildlife without having to use a flashlight and give away your position. This device can help you see bright images even in low-lit environments where the only source of light is the moon or the stars.

Some models come with infrared illuminators while others have integrated photo or video cameras that can help you record the action without having to bring a separate recording device with you.


Experience the world in complete darkness

For nighttime activities where there’s little to no light available, you can also go for a new thermal monocular. This device doesn’t need any light, as is the case with night vision models. It detects small differences in radiations so that you get to see objects, particularly humans and animals, very well.

With a thermal device, you can see animals such as deer and hogs which are usually more active at night when there is little light. You can also use it for surveillance purposes, or even to detect heat that’s leaking from your home through various parts, such as the windows, the attic, or a poorly insulated wall.

Many thermal monoculars are small and lightweight so that they can be used for long periods of time without tiring your hands, and they also have a long battery life for extended operations.


Get a portable device to see the stars

While not exactly the best devices for stargazing, monoculars can successfully be used to admire the night sky. Telescopes would surely be a better candidate for this, but would you really be able to carry a 20 or 30-pound telescope everywhere you go? A monocular is lightweight and can fit into a pocket so you can take it with you anywhere.

You could carry a monocular with you and make sure that you have it ready when asteroids and comets show up in the night sky so you can get a much better view, or show your friends how the Moon looks like under a clear sky away from the city lights.


A rugged monocular can work in the harshest environments

There are many optical devices out there that are fragile and can get damaged easily. Fortunately, monoculars are not among them. These rugged devices are usually made from hard plastics or even magnesium alloys and feature rubber armors on the exterior which not only provide a good grip but also protect against mechanical damage.

Some models also feature anti-fogging technologies so that you won’t get a blurred view due to moisture condensing on the front glass element. Many others are waterproof so you can use them in wet environments or even when it rains without fearing damage.

Admire your favorite artists up-close

If you prefer to go to the local theater and opera or attend concerts from time to time, then a monocular can help you get a much better view of the event as well as the artists. You can watch your favorite play and actually get to see the faces of the characters, enjoying an enhanced experience where you can watch every display of emotion.

At concerts, you can admire the lead guitarist’s solo or check the latest equipment of your favorite band. With a variable zoom monocular, you get a lot of flexibility without much effort, especially since you won’t be watching any high-speed action at a musical venue.


Enjoy a device that’s small and compact

So if you want to make sure that you are ready for any sort of activity, whether it’s hiking in the mountains, exploring nature during the night, or heading over to see your favorite singer, getting a small and lightweight monocular is the best way to ensure that you get to see everything in high resolution while also benefiting from an affordable device.




How to understand the difference between binoculars and monoculars?


Judging by looks alone, a monocular appears as something in between a binocular and a spotting scope. It has a similar objective diameter to a binocular, and it is usually used without a tripod, but it only allows for magnification for one eye, like the much larger scope. The relevant specifications are also fairly comparable to those of binoculars, as well as features such as the prism design or the lens coating used. It won’t be entirely off to basically call a monocular “half a binocular,” which the name itself suggests.

In fact, the main differences between the two can be boiled down to size. A monocular will always be smaller, lighter and easier to carry than a comparable binocular. Less than half of that, in fact, since the ridge holding the two barrels together won’t be present. A single cylinder will also be a lot easier to fit in a pocket, or in a bag with the rest of your belongings, compared to a relatively wide frame.

So if storage space is a major issue, then the monocular will be the favored option, especially as they can get pretty small in length as well. There are some excellent monoculars for sale that are about the size of a human thumb, and no wider than a hefty pen. These are great for casually carrying them around inside your pocket or purse, to be popped out whenever something requires a closer look, like the firm on a far away store or the license plates on a car. In other words, smaller monoculars can act as objects to be worn on a regular basis, instead of situationally.

Now, they *can* offer similar functionality to binoculars for outdoor use, since many of them come in the appropriate aperture size. For example, a 10×50 monocular will potentially make the image appear as close, as wide and of a similar quality to what an equivalent binocular might provide, with the obvious difference of only allowing you to follow it with one eye.

This can offer some benefits in certain conditions, but is considered a downside. First, looking through the monocular for long will prove to be much more of a strain compared to a double piece. Our eyes aren’t designed to work independently from one another, and concentrating on the image coming from either one will make you fatigue very fast.

All else being equal, the number of vision tubes used on a magnifying device shouldn’t seriously impact the maximum field of view allowed (which is how much of the background fits in the image), since this is factored by objective size, magnification, and ultimately lens shape. So on paper, it should be as easy to follow moving objects with a monocular as with a binocular.

But confronted with reality, this will usually not be the case, since both the formerly mentioned eye fatigue and your attention being constantly drawn to what the naked eye is seeing will make it hard to concentrate and keep track of what the monocular is trained on.

This can be somewhat circumvented with proper training, and it might prove less troublesome for army sharpshooters or hunters that are already familiar with using a scope, but for your regular Tom, Dick, and Harry, the binocular will always be a better option when scouring the horizon for any amount of time. That’s why mono eyepieces aren’t recommended for activities like stargazing, bird watching or hunting, but will surely prove useful for getting your bearings during a nature outing!

Another thing that might worth bearing in mind when choosing between a binocular and monocular is that proportional to their size and weight, the single barrel variety will always be more powerful, assuming all else to be equal. This might tip the scales if you want maximum magnifying power and an acceptable field of view from a unit you aren’t expecting to contemplate the scenery with. If the eyepiece is only used for taking a snap at a far away peak, for example, then there’s no reason to have a second tube to take up space.

Monoculars intended for outdoor use have the same functionality as their doubled cousins. They have relatively large objectives, commonly sized between 35 and 50 mm, to allow for a lot of light in, coupled with a high magnification power (8x, 10x, etc.) and special reflective coating on their lens and prisms to give them the best brightness possible.

Sturdy frames are used, generally coated in rubber to resist accidental impacts with rocks or tree branches, and a level of fog and water protection is added, so that the inside of the lens doesn’t condense. Some of them are even safe to be submerged and can float.   

However, smaller units are usually found to be preferable for the convenience they offer, and maximum magnification tends to be traded for ease of handling and eye comfort. Since it’s considered particularly hard to keep a powerful monocular trained on a target without a tripod, a magnification of 6x is found to be ideal by most users to give you a steady image that’s easy to follow.

These smaller units can also effectively double as magnifying glasses to a far greater extent than binoculars. First, monoculars allow for a smaller minimum focus, in the range of inches instead of feet. Second, most models can be simply turned around, and the near objects on the other side will appear clear.  

A final thing that might recommend a monocular is your own vision’s peculiarities. This might seem obvious, but people that suffer from poor or no vision in one eye might not need two oculars.  




How to understand monocular numbers and other daunting features


Buying a monocular can be pretty intimidating with all the technical manufacturers give for their product, and some research is required to ensure that you get the right one for the task you have in mind. As we’ll see, simply going for the biggest numbers just won’t do in the case of optics, and selecting them based on cool-sounding features that you won’t use will just needlessly empty your wallet. To get you properly informed, we’ve explained some of the most important specs and features to look for when choosing a monocular.

Colloquially referred to as the “power” of the monocular, the two numbers that are most commonly associated with this particular instrument refer to the magnifying power and the size of the objective — which is the front lens of the piece. The magnification factor will appear with an x after it, followed by the number for the objective diameter, expressed in millimeters.

Deciding on the right magnification is the first choice you will have to make. Naturally, a higher magnifying factor will let you clearly see things further away, but it will also decrease your field of view and make the piece hard to steady. It’s quite a challenge to keep the image from shaking with 8x monoculars, and most people can only effectively use a 10x piece attached to a tripod. If you’re looking for a new monocular for hiking, then a 6x factor will usually do quite well. You can get away with even less than that if your intended purpose is casual use, around parks and urban areas.

The objective lens diameter determines brightness and is correlated with the magnification factor, as powerful monoculars need a lot of light to enter the aperture for a clear, bright image to be formed. You should look for big lenses if you intend to use the monocular at night, but be warned that this comes at the detriment of portability, since a wider objective means a more sizeable, heavier frame.

The field of view refers to the portion of the horizon you’ll be able to see through the monocular. It is either expressed in units of size, at a set distance of 1000 yards or at an angle. This further breaks into the apparent angle, which denotes how wide your vision cone will be if hypothetically sitting in a spot as close to the image as the monocular makes it appear; and actual angle, which is self-explanatory, and expectedly much smaller. Most manufacturers use units of size and sometimes the apparent angle to denote the field of view, while the actual angle is almost never specified.

Field of view is particularly important if you need to keep track of fast moving objects, such as birds, but seeing more of the background will increase your situational awareness in any circumstance.

Besides the shape of the lens and magnification factor, the field of view is further determined by the type of prism the monocular uses. There are two common designs, the Porro, which has been around for a couple of hundred years, and the slightly newer roof prism. Out of the two, the Porro naturally offers a clearer, crisper image and a wider field of view. Where it fails, however, is convenience and portability. Porros are regarded as frailer, and they make for a bulkier design as the objective and the exit lens are not in line. The roof system allows for a streamlined design, with a little protuberance on one side to fit the prism.

The glass used for the prism also plays a role in the quality of the image you’ll be getting. If you want the best clarity and brightness available, then you should go for BAK-4, that has nearly no internal reflection. Today, this glass is cheap enough to be used even on affordable models, but if you’re really stingy with your wallet than the less performing BK-7 will have to do.

Glass is naturally reflective (around 4% of the light received), which can negatively affect clarity, but also brightness since less light will end up hitting the retina of your eye. A magnesium fluoride coating is used to combat this problem, applied to either one or more of the surfaces light will be hitting. If a manufacturer specifies a monocular or binocular as “coated,” this means that not all the optics inside have received this treatment.

When all the potentially reflective surfaces have been coated, then the piece will be deemed “fully coated.” Sometimes multiple layers are applied on one or more surfaces, which will rate the monocular as “multi-coated.” If all glass bits have been multi-coated, the instrument will be deemed “fully-multicoated”.

The “exit pupil” refers to the “rod” of light that will be hitting your eye after passing through the optic device. Its diameter should be at least as large as that of your pupil at the time. Otherwise, you’ll be seeing a dark border around the image. The exit pupil is sometimes specified but can also be easily determined by dividing the diameter of the objective by the magnification. For example, an 8×42 piece will have an exit pupil of 5.25 mm. You generally won’t need more than that, since a human pupil will only grow to about 7 mm in near pitch black conditions.

Eye relief will be important for glass wearers, as it denotes the furthest point from the exit lens at which the image will appear in focus. Most regular framed glasses sit at around 14 mm from your eyes, so check that the monocular allows for at least that.




Ioana Moldovan

Ioana’s professional experience in the optics field has helped her understand the value of passing her knowledge forward. Her curious personality helps her gather useful information for her readers and her goal is to make technical information fun and accessible to everyone.

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