Ultimate Guide to Binoculars

Ultimate Guide to Binoculars

Binoculars are great tools that people can use for a variety of purposes. 

Many people use binoculars for hunting, hiking, wildlife viewing, birdwatching, sports, and theatre.

They also come in many different sizes, which make them even more versatile for different events. 

If you don’t know a lot about the popular tools, it may be confusing to use them for the first time.

It will also be hard to choose your first pair since there are so many different kinds of binoculars. 

Fortunately, this guide will explain everything you need to know about binoculars.

By the end of this article, you will know how to choose the perfect pair and how to use them. 

We will cover what binoculars are and how they work.

This guide will also get into the details and explain the different types of binoculars, the meaning of the numbers, and more. 

If you are ready to learn more, keep on reading. 

What Are Binoculars? 

What Are Binoculars? 

Binoculars are optical instruments with two refracting telescopes mounted side by side, allowing the viewer to see distant objects.

The two telescopes are mounted facing the same direction, so users can look with both eyes through the telescope.

Most binoculars will have a thumbwheel that can control the focus of the two lenses for both eyes.

Sometimes users can also adjust each telescope individually. 

Since binoculars allow users to use both eyes, it feels more natural than using a telescope would.

The optical instrument improves visual acuity and allows for accurate depth perception.  

How Do Binoculars Work?

How Do Binoculars Work?  

Now that we know what binoculars are let’s find out how they work. 

The main job of binoculars is to make objects that are far away easier to see. The instrument uses lenses and prisms to do this. 

Lenses and Prisms

Lenses are curved, circular pieces of glass. Prisms are made of glass as well, but they have flat sides instead of curved ones.

When light travels through a pair of binoculars, the lenses and prisms will change the direction of that light and therefore change the image that people see. 

The prisms you find in binoculars are usually called reflective prisms, and each instrument has two.

The reason that binoculars need these prisms is that the initial image that the telescopes pick up is inverted.

The main job of the prisms is to reinvent the image.

These prisms also allow binoculars to have a shorter length than typical telescopes since the prisms provide a folded path for light rays. 

The Exit Pupil

Another important part of binoculars is the exit pupil. The exit pupil refers to the width of the incoming light beam that comes through the eyepiece. 

Larger exit pupils are better since they make the image a lot brighter.

In contrast, small exit pupils are less bright and do not work well in low light conditions. 

The Process

We now know all of the individual parts that make up binoculars.

Let’s see what process occurs when one uses a pair of binoculars. 

  1. Light enters the objective lens. 
  2. The lenses convert the image and flip it upside down. 
  3. Light passes through the glass prisms. 
  4. The prisms take the image and turn it around again, reflecting it towards the eyepiece. 
  5. The light travels through each eyepiece and reaches the eyes. 

Meaning of Numbers of Binoculars

Meaning of Numbers of Binoculars

Even if you know the basics of how binoculars work, it is essential to understand the meaning of numbers. Let’s find out. 

The First Number

Binoculars have two numbers that describe the primary optical characteristics of each pair. The first number is followed by a multiplication sign.

This number represents the magnification level of the binoculars. 

For instance, if the first number of your binoculars reads 10x, it means that it magnifies the image ten times more than your naked eye.

The object will appear to be ten times closer when you look through the lens. 

The Second Number

The second number on binoculars refers to the size of the objective lens. This size is measured in millimeters. 

Say your binoculars have numbers that read 7×43. This means that the objective lens has a diameter of 43 millimeters. 

This measurement refers to how well the binoculars pick up light. The higher the number, the more light the binoculars will pick up.

Smaller sizes such as 30mm will not work well at night, but binoculars with a 150mm objective lens will allow you to see well even in low light. 

Furthermore, as the diameter of the objective lens increases, the sharper and brighter the image will be. 

Types of Binoculars

There are many different kinds of binoculars. Before you buy a pair, you should think about what activity you want to use the binoculars for.

Different types of binoculars are designed for certain things, such as stargazing or birdwatching. Let’s take a look. 

Porro Prism Binoculars

Porro Prism Binoculars

Porro prism binoculars were first developed in the nineteenth century.

When light travels through Porro prism binoculars, it travels through a pair of light-catchers in a horizontal jag motion.

This process is what inverts and amplifies the light, which produces the magnified image. 

The one downside of these binoculars is that they are a bit bulkier than other kinds.

Furthermore, Porro prisms have many moving internal parts, which makes them a bit harder to upkeep and take care of. 

However, many Porro prism binoculars are affordable since they are cheaper to make than roof prism binoculars. 

Roof Prism Binoculars

Roof prism binoculars are one of the two modern styles, the other modern style being Porro prism binoculars. However, this specific style is the newest.

These binoculars are more compact and much slimmer than other styles. Since roof prism binoculars are straight tubed, they are also lightweight and sleek. 

Many people can identify these optical instruments easily since the objective lenses and eyepieces align with each other. 

Roof prisms have fewer internal parts than their counterpart, the Porro prism binoculars, making them easier to take care of. 

Furthermore, these binoculars can produce brighter images and higher magnification power.

This is because the light bounces around a lot more as it travels through the instrument. 

However, these features come at a higher cost. Most roof prism binoculars are in the higher end of the price range. 

Night Vision Binoculars

Night Vision Binoculars

If you want to do some sightseeing at night, such as wildlife viewing, you will need to use night vision binoculars. 

These kinds of binoculars produce high-quality images in low light conditions.

They use electronic optics to amplify all of the available light with photon-enhancing components.

This process then produces an image that is bright and detailed enough to see clearly. 

Night vision binoculars tend to be much more expensive than others and are very fragile.

Many people use these binoculars for various activities such as hunting, surveillance, spelunking, and exploring. 

Astronomy Binoculars

Surprisingly, astronomy binoculars come in a lot of shapes and sizes. Some are small enough to fit in a pocket, while others will need a tripod

These optical instruments will produce a wider field of view compared to telescopes, making them great for stargazing.

The barrels in astronomy binoculars also pick up more light, which increases the clarity of the image. 

Many people prefer astronomy binoculars over telescopes since you can use both eyes.

This will allow your brain to form a more accurate image since you gather more data with both eyes instead of one.

It also feels more natural compared to having to close one eye. 

Marine Binoculars

Marine Binoculars

If you will be near the water while using binoculars, you will want to get a pair of marine binoculars. 

These optical instruments are designed to perform well around water and in humid, wet environments.

Most marine binoculars have wide ocular and objective lenses.

They also tend to have low to medium levels of magnification and a wide field of view. 

These binoculars do not have high magnification power because any sort of movement can potentially blur a magnified image.

While it is relatively easy to keep binoculars still on the ground, it will be next to impossible to prevent movement on a boat. 

Furthermore, marine binoculars are typically waterproof and do not fog easily. 

Opera Glasses

Much like binoculars, opera glasses have been around for centuries. Many people use modern opera glasses for theatre, musical and opera shows.

It is quite difficult to see details of the performance from most seats when attending a theatre show. 

Opera glasses typically only have a max magnification power of 4.

Since users tend to use the glasses for long periods, a high magnification power could cause eye strain.

Four will also be a good enough power for theatre shows. 

Field of View Explained 

Field of View Explained 

All binoculars have a different field of view. Some instruments have a narrow field of view, while others have wide fields of view. 

Field of view refers to how much of the landscape you can see in your lens or how wide an area you can see. 

When you have a wide field of view, you can easily see things without physically moving the binoculars.

However, with a narrow field of view, you will need to move the binoculars more to take in a larger land area. 

Binoculars given field of view is a byproduct of the diameter of the objective lens and the power.

Typically, binoculars with high magnification power will have narrower fields of view.

However, instruments with low power will have a wider field of view. 

If you want a more detailed and clear image, you won’t see as wide of an area in your lens.

On the other hand, if you lower the quality of the image, you can see a larger area of the landscape through your lens at any given time. 

Binocular Lenses 

Binocular Lenses 

There are two types of lenses in each telescope; an objective lens and the ocular lens (also called the eyepiece lens). 

The Objective Lens

The objective lens captures the initial image and takes in light. Furthermore, the objective lens is convex.

This means that the lens is thicker in the middle. This characteristic causes the light to bend and refract, which guides it towards the middle.

What this process does is allows the lenses to focus distant light rays into a smaller image. 

The Ocular Lens

The main job of the ocular lens is to magnify the image. It picks up the image, and just like a magnifying glass, it makes the image bigger and easier to see.

The ocular lens is what allows us to see details on objects that are far away. 

Lens Coating

Something else that is important when it comes to lenses is the lens coating.

Lens coatings greatly reduce the amount of glare you see and will produce a clearer image.

It also allows more light to enter the lens, which increases the amount of detail as well. 

There are four types of coatings: coated, fully coated, multi-coated and fully multi-coated. 

  • Coated: If your binoculars are coated, it means that at least one of the lenses has a single layer of coating on them. 
  • Fully-coated: A fully-coated instrument means that all air-to-glass lenses have a single coating. 
  • Multi-coated: Multi-coated means that at least one lens has multiple layers of coating.
  • Fully multi-coated: If your instrument is fully multi-coated, it means that all air-to-glass lenses have multiple coatings on them. 

Binocular Maintenance 

Binocular Maintenance 

Binoculars are not cheap. If you are thinking of getting a pair, you should know how to take care of them to prevent costly repairs. 

How To Take Care of Binoculars

Keep the Lens Cap on When Not in Use

When you are not using your binoculars, make sure to keep the lens caps on. Doing so will prevent scratches and dust from getting in the lens.

This tip is especially important to remember when you are in harsh conditions such as on the ocean or in a dusty environment. 

Store Your Binoculars in a Protective Case

One of the main things to avoid is storing your binoculars on a shelf somewhere without any protective casing.

It only takes a second for your binoculars to fall and break or experience some damage.

Make sure to keep your optical instrument in a waterproof protective case.

Always Keep Your Binoculars Around Your Neck or in a Harness

Try to always keep your binoculars in a harness or around your neck while on the go.

If you hold it without any straps, you could possibly drop your instrument and damage it.

This tip is especially important when you are hiking or on a boat. 

Don’t Leave Your Binoculars in the Car

It may be tempting to throw your binoculars on the seat while taking a quick stop on the road.

However, leaving them in the hot sun could lead to damage. Furthermore, make sure to keep them in a secure spot while driving to avoid them from flying around. 

Be Careful When Using Your Binoculars in the Rain

Water and binoculars do not mix unless you are using marine binoculars.

When it starts to rain, keep your binoculars covered. You can do this by using an umbrella or simply finding a roof to duck under. 

You should avoid rain (heavy rain, at least) at all costs because water can leak into the main housing of the instrument.

The water can carry dirt with it, which can damage internal parts.

Make sure to place your binoculars in a dry and warm area if they start to steam up and let them dry for a few days.  

How To Clean Binoculars 

Removing Debris

You can use a few tools to remove minor debris from your handy binoculars: an air blower, lens cleaning wipes, lens cleaning brushes, a spray bottle and microfiber cloths. 

To remove small dust particles from the lens, use a lens brush or an air blower. You can also use a spray bottle to rinse off dust and dirt. 

When cleaning your binoculars, never use too much force. Always use light strokes to avoid external damage. 

Removing Grease

When you want to remove grease or fingerprints from your optical instrument, you can use cleaning cloths or microfiber cloths to do the job. 

However, use an air blower or a brush on the lens before coming in with a cloth.

Doing so will avoid dust and dirt particles from scratching the lens.

Binocular Accessories 

In this section, we will take a look at some binocular accessories that may come in handy.

From harnesses to cleaning pens, all of these tools will be useful at one point or another. 



If you are doing something more physically demanding, such as hiking, hunting or climbing, investing in a binocular harness might be a good idea. 

Using a harness will prevent the binoculars from bouncing around too much while you move.

You can tighten the straps according to your comfort and make sure your optical instrument stays put. 


If you will not be climbing over rocks or jumping over small creeks, you probably won’t need a harness.

However, you should still have a way to keep your binoculars safe. 

Binocular straps are very useful and will keep your optical instrument safe around your neck.

With this accessory, you can have access to both hands when you are not using the binoculars. 

Eye Shields

Eye Shields

This accessory is optional. Not everyone will need eye shields for their binoculars. 

The main purpose of eye shields is to prevent you from getting distracted by activities around you.

It will also block sunlight. Ultimately, eye shields will simply improve your experience.

It will help you focus on the image more instead of the environment around it. 

Eye shields will be a good choice for those using binoculars in crowded areas.

However, if you mostly use binoculars for wildlife viewing in natural environments, you will probably be okay without them. 

Cleaning Pens

Cleaning pens are great little tools to bring along in your backpack or fanny pack. One set will typically come with three pens.

You can use the small brushes to remove dust and debris from the lenses. 


Another essential accessory is a binocular case. Binocular cases will keep your instrument safe and secure when you are not using it.

Most cases are padded and will even keep your binoculars safe if you drop them. Investing in a case is essential to prevent costly damage.

Binoculars and Glasses

Binoculars and Glasses

Depending on the model you have, you may experience a bit of trouble using binoculars with glasses; it will all depend on the eye relief. 

Eye relief refers to how close your eyes should be to the eyepiece to experience the best image.

If you wear glasses, you may be too far away from the eyepiece, constricting the image.

So if you wear glasses, you should keep this in mind when buying your first pair of binoculars. 

What Eye Relief Should My Binoculars Have if I Wear Glasses? 

The last thing you will want is a cut-off image when you look through your binoculars.

Fortunately, you can buy certain models that will work well with glasses. Make sure to buy a pair with long eye relief.

The minimum eye relief your optical instrument should have is 16mm. However, anything that is more than 16mm will work better. 


We hope that this ultimate guide to binoculars covered everything that you needed to know. 

Binoculars are optical instruments that have two telescopes mounted side by side.

People use binoculars for various activities such as birdwatching, hunting, and hiking to see far away objects. 

There are a few essential things to know about binoculars. When it comes to the numbers, the first number refers to the magnification level of the binoculars.

The second number represents the size of the objective lens. 

Another thing to keep in mind is the field of view. Each model will have a certain field of view; this factor will affect how the image looks in your lens. 

If your instrument has a narrow field of view, you will need to move your binoculars more to see a wider area.

However, if you have a wide field of view, you will see more land in the lens without moving it. 

After you buy a new pair of binoculars, make sure to take care of them to avoid costly damage.

You can do this by using a case, buying a harness, and protecting them from the rain.