What Do The Numbers On Binoculars Mean 2021

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What Do The Numbers On Binocular MeanBinoculars are the most vital accessory that you can have while going on a trip. If you are someone who loves nature, having a pair of binoculars is going to make it so much better for you.

Yet, choosing the right binoculars is not always an easy job. Especially, people get confused by the numbers a lot. So, what do the numbers on binoculars mean, and how do you know what’s better than the rest?

To help you with that, let’s go over different stuff that you might want to know about it.

Binocular Terms: What You Need to Know

Binocular terms can be pretty confusing if you are new to this. But if you want to get the concept down, you need to know what the terms are and what they mean. Down below, let’s explain all the terms and numbers so that you can get clear on the concept.

Objective Lens Diameter

The objective lens diameter shows how much light the lens will allow passing. That means, the higher the number is, the brighter the image is going to be as well. Also, it’ll give you better contrast and true color in the picture, which is fantastic.

You should go for at least 30mm to 42mm, as it’ll give you a radiant picture in the field. But as you increase the number, the weight of the binocular also rises. So, be mindful of that while you are picking one for yourself.

The first thing you should know about the binoculars is the objective lens diameter. It plays a huge role in telling if the binocular is right for you or not. Better ones will have a higher lens diameter than the other ones. That’s how you can tell how bright an image you are going to see.

What Do The Numbers On Binoculars Mean

You know that contrast and light are very vital for seeing things that you want to see. That’s the reason why you should always go for a pair of binoculars that have a higher objective lens diameter in general.

Most of the premium ones in the market also have a high lens diameter as well. Those are great at transmitting the light and giving you a brighter picture.

But as you can tell, it’s going to be a bit more pricey than the rest. But it’s still worth the money. So, if you can afford it, go for a binocular that has a higher optic diameter.

Magnification power

You’ll see most binoculars use numbers such as 7×30, 8×40, and so on so forth. The first number in this sequence represents the magnification power. For instance, the 7×30, the magnification power is 7.

That means you can zoom 7 times with the binocular. And if you are using a 10x, you’ll be able to see the objects appear 10 times closer to you than the naked eyes.

You need to know this to get a clear concept of binoculars.  You see, the main use of it is to see images of a distance. So, you must know how much distance your binocular can cover. And to know that, you must understand the numbers, which tells you that.

If you are asking how much magnification is better, it depends on your style. Usually, a 7x to 10x is what you’ll need in most cases. But you can go for even greater numbers as well. But that will cost you a bit more money.

That’s why you should be practical while choosing the magnification and think about what do you need. That way, you’ll be able to get the perfect fit with ease. And you see, it’s also not that hard to get down the concept pretty well.

Understanding Angle of View

The angle of view tells how broad of an image your binocular is going to show you. It’s usually measured in degrees in most cases. Also, you should know that the measurement counts as the width of your view at 1000 yards away from you.

For instance, an 8×32 can have a certain angle of view. You should take note that the more powerful the binocular is, the less angle of view you are going to get. It’s like the rule of thumb.

Yet, the narrower angle of view is not so bad, as it’s going to give you more sharpness and precise image. So, if the image quality is your concern, you should choose a binocular that has a more narrow-angle view.


On the other hand, if you choose to get one that has more angle of view, it’s going to compromise the image quality a little bit. That’s because more of the image projects in the binoculars, which makes it hard to get a sharp and precise image.

So, that’s all there is to it. If you want to choose for yourself, you can do it with ease now. You just have to know how to use your pair of binoculars the most. And according to that, you can select the angle of view.

Understanding Field of View

The field of view tells you how much distance your binocular can cover. People measure the field of view in feet, and it’s worldwide as well. Also, it measures the width of your view for 1000 yards of distance.

So, for instance, an 8×32 can have a field of view of 400 feet at 1000 yards of distance. That tells you how much distance the 8×32 can cover for you.

This piece of information is very vital for you to know. As you know, binoculars are for letting you see what’s at a distance. So, you can pick your binocular according to how much far off your object might be.

As you go for the more powerful ones, it’s going to get more costly. Also, you are going to lose some angle of view as well.

Yet, it’s always best to invest in a pair of binoculars that can provide you with a bit more of a field of view that you primarily need. That’s going to make it more flexible to use for you, and you’ll be able to use it in all kinds of places as well.

Try to go for at least 300 to 375 feet at a 1000 yard field of view. That’s a pretty good number for you if you don’t want to sweat it all.

Exit Pupil Number

The exit pupil of your binocular is the diameter of that circle of light that can calculate. It’s very easy to calculate the exit pupil by yourself. You have to divide the magnification of the binocular into the diameter of the objective lens, and that’s how you get the exit pupil number without much effort.

For instance, a 10×42 has an exit pupil of 4.2 mm, which you can calculate by the method. You see how easy it is to calculate the exit pupil.

The exit pupil number plays a vital role if you want to know which binocular is better than the other ones. You can just compare the number and decide for yourself.

The 7 mm considers the best exit pupil number that you can get. You might see it in the most popular 7×50 night glasses or such.

But, you can always choose according to your needs as well. It’s better to get one that’s close to the 7mm, as it will give you the best dilation just like a human eye.

So, you should consider the exit pupil number when you choose a binocular for yourself.

What Are The Numbers On Binoculars

Minimum Focus Distance

The minimum focus distance of your binocular should be 1 to 2 meters at max. You should go for the shorter minimum focus distance as it helps to give you the most detail and sharpness in the picture.

As you can tell, the most premium binoculars in the market have a shorter minimum focus distance. That lets them give the sharpest and detailed image to you.

Yet, those are pretty costly. So, you should consider what you need in terms of quality. If you don’t want to compromise the quality for money, you can go for a shorter distance. It’s going to pay off very well at the end of the day.

But if you can’t afford it, you don’t have to sweat it. Just go for a good product in general. And make sure not to exceed the 1 to 2-meter number by a lot. Try to stick closer to that range as much as you can.

And of course, if you want to invest in a premium one, you must check the minimum focus distance and see what the number is? That’s going to tell you a lot about the binocular.

Eye Relief

If you wear eyeglasses, eye relief is a must-have feature for your binocular. The best distance for eye relief is at least 16 mm. And if the number exceeds that, it’s even better.

In most cases, you’ll find that the binoculars come with a 15mm eye relief or even less at times. This is not the best distance to be at, of course.

You should get binocular that has eye relief in it. It’s going to help you so much if you wear glasses. It helps to put your eyes at a distance that is very comfortable to look at the objects through the eye caps.

You should know that most of the binoculars these days feature eye relief, and it’s very common. So, there is no reason not to get such binoculars as it might come in handy.

Now, you might think that eyecup twist is enough to get the eyeglass wearers closer, but it’s not well enough. You need eye relief on your binoculars to get the best results, whatever you do.

And you should also do some research on wearing eyeglasses while looking at a binocular. You might not need to wear them at all at this time just because it is going to autocorrect your vision in most cases.

Prism Type

You might know that there are two main prisms in binoculars that are roof prism and Porro prism. The Porro prisms will give you a better quality of an image in general.

But the roof prism is also a great option to go for. Those usually have a more complicated structure, which you’ll see as an “H” shape design in most binoculars. Also, you’ll see that in the roof prism, the lenses and the tubes are in a straight line.

If you want a more bright picture and more contrast as well, the Porro prism will be the best option for you. But the roof prism will give you a better optic precision than the Porro prism.

Also, you should know that the roof prism is a bit more pricey than the Porro prism. But in general,  you should invest in a good pair of roof prism binoculars.

You see, it’s not just about what do the numbers on binoculars mean but also about the different features as well.

Chassis Materials

The chassis material plays a vital role in determining how durable the binocular is. Most of the binoculars use magnesium as the chassis material. Also, you’ll find some that use aluminum chassis in the construction too.

Now, to compare these two, the aluminum chassis is a bit better option for you. Just because it’s lighter than the magnesium, which is pretty awesome.

You know the weight is very crucial because you’ll have to carry it around with you all the time. And what can be more annoying than a super heavy binocular on your straps? That’s why most people prefer aluminum chassis better.

So, while you pick yours, you should consider checking the material used as well. It will give you an idea if it’s going to last you better or give you the comfort that you crave.

What is a BAK-4 prism?

BAK-4 prism is a great optic structure that most premium binoculars use. They use superior optic glasses, which gives you the best clear and precise image.

You can also find BAK-7 prism glasses in cheaper binoculars. Those do not have the sharpness, light, and detail if you compare those with the BAK-4 prism.

Also, the BAK-4 has a truer round, which allows it to transmit light better and thus, gives you a radiant image. All the premium binoculars use the BAK-4 in them to provide you with the best contrast and light.

But the only downside with the BAK-4 is that it’s costly. You’ll have to pay extra to get the topnotch quality of these great optics. So, if you don’t like to compromise the quality for the cost, the BAK-4 is perfect for you.


Binoculars use a coating to prevent internal light loss and glare from the view. It’s a great feature to have, and without coating, it’s very hard to get a clear view of the objects.

It promotes light transmission and gives a more bright image. There are two types of coating that you can find in most binoculars. You’ll find fully coated and multi-coated binoculars.

The multi-coated ones are a better option for you as it gives a more clear and precise image. Those have a layer of multiple coating on all the glass surfaces.

You can tell how it helps to transmit light and give a brighter view. And a radiant view is a very important feature to have in a binocular. It helps to give you a better experience while using it.

Also, it helps to reduce the glares, which is very annoying. It destroys the whole thing and ruins your moment. And the coating helps to get rid of it, which is very nice.

Housing Styles

This is similar to the prisms in a sense. But it’s not the same thing, that’s for sure. There are three housing styles that you can find on binoculars.

The first one is, of course, the “H” style. You’ll see that roof prism binoculars use this housing style in them. This is a bit complex in the structure and provides more accuracy and precision of the optics.

The second one is the German style. It’s also known as the Bausch & Lomb style. The Porro prism binoculars use this housing style in those.

The final housing style is the American style. That looks pretty similar to the German housing style. But in reality, it’s quite different in the structure and the context as well.

Now, you have to choose from those styles and go with the one that suits you the most. The best way to go would be the “H” one, which is the roof prism design. It provides you with the most accuracy, that’s the critical thing at the end of the day.

Waterproof and Weather-Resistant Binoculars

The waterproof binoculars are a great pair of binoculars that you can have for yourself. But take note that no binocular can give you the perfect resistance from the water. It’s going to leak water at one point or the other.

Yet, it’s great to have this feature for a lot of reasons. The most critical reason is that you are going to travel a lot with it. So, it might slip out of your hand and fall in the water. That’s why having this feature can benefit you a lot.

And the weather resistance feature is another fantastic thing that you can have as well. It helps you in a lot of scenarios.

It can be fog resistance, which is pretty common these days. Those are very nice for the cold weather. You don’t have to worry about the moisture buildup inside your binocular if you have fog resistance.

You can see how you can benefit from those features in most cases. So, I prefer you to take a look at those extra features before you buy one for yourself.

It’s going to take a bit more money for you to but those with extra features. But it’s a very worthwhile investment at the end of the day.

What Do The Numbers On Binoculars Mean

How do I Know Which Binocular is to Pick?

Now that you have a basic concept of all the numbers and terms, you can pick the right binocular for you with ease. You just have to consider the most vital things before you choose to spend your money on one.

The first thing you should look at is the lens size and the magnification. Those two will set the foundation for the perfect binoculars for you.

After that, you should look at the angle of view and the field of view as well to get the best out of your binocular. You should consider taking a look at what distance you are going to be working on the most. And then, you can pick accordingly.

Check the exit pupil diameter and see if it’s a good fit. And if you wear eyeglasses, you should go for the one that has an eye relief of 16mm or more.

Now, you can also check the prism types and the materials. Try to go for a binocular that uses Aluminum material. And also, look at the coatings and see if it uses a multi-layer coating or not.  And finally, see if the binocular has some extra features that you can use in the field.

But sure, the budget is going to be the biggest issue. Remember, you don’t have to go for the most pricey one in the market to enjoy a great experience. Just pick a good one that doesn’t break the bank for you, and you’ll be good to go.


That was a lot of stuff on what do the numbers on binoculars mean. As you saw, it’s not that hard to get the concept down. You just have to pay attention to it a bit, and it’ll all be clear for you.

Also, now you should be able to pick the best pair of binoculars for yourself. Just make sure to follow what you’ve learned so far, and you’d be good to go.

And remember, you deserve the best experience on your trips, and you should invest in a good pair of binoculars to help you get it easily.


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