What Do The Numbers On Binocular Mean? 2023 Guide

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Have you ever wondered what those numbers on your binoculars actually mean? Look no further because in this blog we will decode the mystery behind the numbers on binoculars.

Numbers on binoculars refer to the magnification power and objective lens diameter, with the first number indicating magnification and the second number representing the diameter of the objective lens in millimeters.

Let’s take a closer look.

The first number (e.g. 8×42) indicates the binocular’s magnification power. This means that the image you see through binoculars is 8 times larger than it is with the human eye. The second number (e.g. 8×42) refers to the binocular’s “aperture” or “objective lens size.” This is the front lens size of the binoculars, expressed in millimeters. A binocular with a larger aperture will gather more light, making it better for low-light conditions like dawn or dusk.

The final number in the binoculars’ description (e.g. 8×42) is the “exit pupil.” The light beam that leaves the binoculars and enters your eye has a diameter of this size. A brighter image result from a relatively large exit pupil because more light is entering your eye.

So, This article aims to guide beginners about numbers on binoculars. Let’s begin!

What Do Numbers on Binoculars Mean – Infographic

Binocular Anatomy – How to Choose Binoculars

When you pick up a pair of binoculars, you might not think about all the different parts that make them work. However, each component is essential for allowing you to see distant objects clearly. The objectives and oculars are the two main components of binoculars.

The objectives are the lenses in the front of the binoculars that collect light from the object being observed. This image is magnified and projected onto your retina by the oculars, also known as eyepieces.

Between the objectives and the oculars is a series of prisms that reflect and bend light in order to produce an upright image. Without these prisms, the image would appear upside down.

Finally, binoculars also have an adjustable focus knob that allows you to fine-tune the image based on your vision. By understanding the different parts of a pair of binoculars, you can appreciate how they help you to see distant objects more clearly.

Parts of Binoculars

1- Focus Ring:

The focus ring is located near the eyepieces and is used to change the focus of the binoculars. This allows the user to see the target from a long-range or close-up. The focus ring can be turned clockwise or counterclockwise. However, the amount of turn needed depends on the binoculars and the distance of the object.

Once the object is in focus, the binoculars can be moved closer or further away from the eyes to fine-tune the image.

2- Diopter Adjustment:

When looking through a binocular, you may notice that the focus wheel on different models is located in different locations. This is due to the fact that the focus wheel adjusts the diopter, which is a unit of measurement for a lens’s refractive power. You can make the focus smoother on your binoculars using the diopter adjustment.

By turning the focus wheel, you can change the distance at which the binocular is focused. This can be useful when trying to focus on something that is just out of reach.

For example, if you’re looking at a bird in a tree, you would use a higher diopter setting than if you were looking at a mountain in the distance. On most binoculars, the diopter adjustment is located near the right eyepiece.

However, some models place it near the left eyepiece, and some even have separate focus wheels for each eyepiece. It can also be useful for fine-tuning the focus when using a tripod-mounted binoculars.

So, next time you’re using a binocular, take a look at the focus wheel and see how it works!

3- Tripod Adapter Connection

The tripod adapter connection is an important piece of equipment for long-distance binoculars. It allows the binoculars to be mounted on a tripod, which is necessary for stability when viewing distant objects.

Besides that, the tripod adapter provided me with the benefit of protecting my binoculars from damage by preventing them from being accidentally dropped during my previous hunt.

Understanding Numbers on Binoculars

1- Magnification

Binocular magnification indicates how many times the target picture has been magnified to make it clearer. Binocular magnifications serve distinct functions. This number on binoculars is a mixture of two figures, 8×42 and 7×35.

Here, 8x is the magnification power, and 42 is the objective lens diameter. Binoculars with 8x magnification show the image 8 times closer than what our naked eye can see.

The greater the magnification power = The Closer and clearer the object

The numbers help tell the user what binoculars are good at viewing. Thus, some magnification powers of binoculars are below.

Magnification for hunting, we recommend 7x to 10x magnification.
Magnification for bird viewing, We recommend 8×42, 10×42, or 10×50 magnification.
For low light hunting, we recommend 7×50, 8×42, or 10×50 magnification.
For hiking and watching nature, we recommend 7×35, 10×42, and 10×50 magnification.

2- Objective Lens Diameter

The objective lens diameter is measured in mm (millimeters). If a binocular has an objective lens diameter of 8×42, it means it has a magnification of 8 and a lens size of 42mm.

Moreover, it is important to note that when you increase the power of binoculars, the view of the field decreases. The Lens diameter plays a crucial role in image quality.

Larger the lens, the brighter the image. As the diameter increases, the weight of the binoculars increases. We usually recommend 50 mm as it is suitable for the sites where users go for wildlife and bird watching and makes the binoculars easy to carry.

However, Lens diameters are more important for low light and night sky viewing conditions.

3- Field Of View (FOV)

The field of view refers to the area that one gets to see when looking through his binoculars. It is measured either in feet per 1000 yards or in meters per 1000 meters which is more briefly defined as the maximum area you get to see at 1000 yards.

The FOVs in binoculars vary based on their magnification and objective lens. For example, a field of view of 400ft means that if you are looking at something 1000 meters away, the width of field you get to see would be 400ft.

As covered before, the field of view is inversely related to the magnification of a binocular. The smaller the magnification, the wider the field of you and the other way around. It will help if you consider how much magnification and FOV you require. However, the field of view is not expressed in degrees, but the angle can lead us to the field of view.

Suppose the angle of view of a binocular is 7.6 degrees. Now multiply the angle of view, which is 7.6 by 52.5. This gives us a 400ft field of view. Thus, a 7.6-degree angle of view is equal to 400ft FOV. You might be curious why we multiply the angle of view by 52.5. This is because 1 degree is equal to 52.5ft at 1000yards. view.

4- Eye Relief

Binocular eye relief is basically for those who wear glasses. It is the distance from our eyes to the eyecups. Moreover, those who wear glasses can relate that there is a distance between your naked eye and the binocular lens, and if this distance is removed, they can easily miss the target. Thus, glasses wearers should go for binoculars with an eye relief of 15 mm.

Check out our details blog on binoculars eye relief here!

5- Close Focus

The number of close focus on binoculars indicates the distance between the binocular and the closest object on which it can focus. Furthermore, it determines how easily a person can perceive an item with a clear focus.

6- Exit Pupil

The basic calculation for eye pupil number equates it to magnification divided by object lens diameter. It is the size of the dots that appear while focusing on the object.

Through these spots, lights enter your eyes and form a clear image of the object on your retina. In most conditions, the exit pupil number should be greater than 4 mm.

Hopefully, now you know about all the numbers on binoculars.

Numbers on Binoculars – Quick Checklist

Magnification: Magnification power is the number of times the target’s picture has been magnified. Furthermore, the higher the magnification, the more visible the object.
Lens Diameter: It tells how much light enters the lens. Similarly, a larger lens means better image quality.
Field of View: The width of the area you can see with binoculars is known as the field of view. Mostly, high-quality binoculars have a field of view of 300-350 feet.
Eye Relief: In binoculars, eye relief represents the distance from our eyes to the eyecups. Whereas binoculars with longer eye relief, i.e.15mm, are recommended for glasses wearers.
Close Focus: The minimum distance between the binoculars and the nearest object you need to focus on using the binoculars is its close focus. However, it becomes more important when there is a need to magnify very close objects.
Exit Pupil: It is calculated by dividing the magnification by the objective lens diameter and determining the picture’s brightness. For night seeing, for example, an exit pupil of greater than 4mm is advised.

Final Wording

In this article, we have discussed the details of important numbers related to binoculars. If we summarize what these numbers tell, it is how large and clear the image shown with the binoculars will be. Hopefully, this article will help you find the right pair of binoculars, using numbers and features you did not know before. Now it is up to you to pick a binocular that is best for you.

Additional Common Questions

Which is superior, 12×50 or 10×42 binoculars?

The choice between 12×50 and 10×42 binoculars really depends on what you’re looking for from your viewing experience. If a wide field of view is important to you, the 10×42 binoculars could be your preferred option, especially for activities like birdwatching or observing natural scenery, where the ability to take in a larger area can greatly enhance the experience. Meanwhile, if you’re after a brighter image with more intricate detail, the 12×50 binoculars might be the more fitting choice. I recall a time where I sat atop a hill, birdwatching as the sun began setting – the 12×50’s brighter image and detail resolution clearly won out in the lower light conditions. So, it largely depends on the context in which you’ll be using them.

10×50 or 20×50 binoculars – which one stands out?

The 10×50 binoculars are a clear winner here when it comes to usefulness and practicality, outstripping the 20×50 binoculars by a notable margin. The 20×50’s narrow field of view can be quite limiting and, because of their high magnification, they often require a tripod for stable viewing. Should you wish to explore higher magnification options while keeping versatility, a small telescope could be a worthwhile investment. I once had the opportunity to test out a buddy’s 20×50 binoculars, and while they could bring distant objects incredibly close, they left a lot to be desired when it came to a broad, immersive viewing experience. Hence, the 10×50 binoculars are just more practical and reliable for most users.

What is superior between 10×42 or 10×50 binoculars?

The difference between the 10×42 and 10×50 binoculars can be quite discernible, especially when you use them in diverse lighting conditions. The 10×42 binoculars form a solid standard for general usage, providing dependable performance and a balance between portability and viewing quality. However, step up to the 10×50 and you’ll quickly appreciate the noticeably brighter images, particularly as the light begins to fade in the evening or before dawn. I remember a twilight hike I took with my 10×50’s; the improved light collection truly accentuated the creatures that began stirring with the setting sun.

10×42 and 12×42, which is the better pair of binoculars?

When comparing 10×42 and 12×42 binoculars, you’ll find the 10×42’s are more versatile and suitable for a wider range of uses. This is great for novices or those who want a pair of binoculars that will function well in a variety of situations. Meanwhile, the 12×42’s offer greater magnification but require more knowledge and practice to exploit their full potential. Think of a time when you switched from using a smartphone to a professional DSLR; sure, the potential for better results is there, but it also demands a deeper understanding of the tool. Hence, unless you need the extra zoom or have particular expertise, you’ll likely find the 10×42’s more usable and enjoyable overall.