This website is reader-supported. When you buy through links on our site, we may earn a small affiliate commission.

How Do Binoculars Magnify?

Last Updated: 06.12.21


Binoculars make distant things look bigger yet the way the image of an object that is far away is rendered is possible thanks to the various parts these optical instruments feature. Whether you use kids binos or models for adults, these pieces of optical equipment work the same. Find out more about the anatomy of binoculars and the way they work in today’s post. 

Engaging in various outdoor activities such as nature-observing, birdwatching, or stargazing wouldn’t be complete without some quality optical devices such as telescopes and binoculars. Thanks to the latest technological achievements, it is now possible to enhance the image of distant objects or wildlife and do so with minimal effort. 

Binoculars are now part of almost any nature-explorer’s kit. They are a must when it comes to other activities such as hunting or the study of bird plumage. By making distant objects and animals look bigger, they will help you observe wildlife carrying out various rituals or daily activities, learn more about the anatomy of different birds, gaze at planets and stars, or get a better view of your prey. 

However, buying the right binoculars for your needs may not be an easy process since it is not enough to pick a model that is lightweight or looks cool. The quality of the image rendered is the one that counts. The magnification power ensured by a certain model weighs heavily when it comes to certain outdoor activities. 

If you’re interested in learning more about how binoculars magnify and what magnification power is ideal for various activities, this post might be of help. 



How do binoculars work? 

The binoculars we use today have a long history behind. It took hundreds of years and many inventors and scholars to create the pieces used for these optical instruments and for us to be able to use them as we do these days. 

In order to understand the way binoculars work, it is necessary to know how telescopes work since binoculars are two identical telescopes placed next to each other and what the lenses used do. Binocular lenses come in various sizes and shapes and their role is to focus light rays from a great distance so you can enjoy a clear image of the object of interest.

There are different types of lenses that do different things. A convex or converging lens brings distant light rays into focus and makes them come together whereas a concave or diverging lens makes the light rays diverge. Since converging lenses make things look bigger, they are used in optical instruments designed to magnify. 

In order to enable you to see distant things clearly, a telescope makes use of two convex lenses that are placed one in front of the other. The first lens is known as the objective lens since it is the nearest to the object that’s being observed and it is designed to collect light from the distant object and bring it into focus in the eyepiece lens. 

The second lens is the one that picks up the image and magnifies it to take up a large portion of the retina. The magnification ensured thus depends on the focal length provided by the eyepiece. Binoculars are two telescopes placed next to each other yet they come with extra features when compared to simple telescopes. 

Additional parts are needed because the image rendered by a telescope is upside down. While this might not be a problem when the instrument is employed for astronomical purposes since in space there is no left and right or up and down, it is a major inconvenience when using the optical tool to watch birds or to hunt and locate your prey. 

Here is where binoculars differ from simple telescopes. To rotate the image and thus correct its orientation, binoculars make use of prisms that are placed between the objective lens and the eyepiece lens. 

Prisms are blocks of glass that work as a mirror without having the reflective backing of a mirror, though. There are two main prism models and various types of glass used for their construction. No matter their type, prisms have one role and that is to turn the image right-side up. 



When searching for binoculars, you will see that one thing that differentiates the various models available for sale is a pair of numbers such as 7×50 or 8×30. The first number in this pair stands for the magnification ensured by a certain model, which means it describes the degree to which the targeted object is magnified. 

If you see binoculars featuring 7×50 magnification characteristics, then you will see the object of interest seven times closer than you would when viewing it with the naked eye. The second number refers to the physical diameter of the objective lenses featured. 

This diameter is measured in millimeters and gives you an idea of how much light the objective lens can gather from the object of interest. The bigger the second number, the more light is gathered, which translates into brighter images. However, this means that the objective lenses used are bigger and thus the binoculars heavier. 

There are certain magnification specs that are best for certain activities. Binoculars with lower magnification will make it easier to hold an image steady. Therefore, it is not true to say that the higher the magnification power, the better the binoculars. Using the right magnification power for your activities may not necessarily mean using binoculars that come with high magnifying properties. 

Moreover, it is more difficult to keep the image steady when you use higher magnification and you may get blurry or unclear images when moving your hand because the instrument won’t just magnify the targeted object but also the effects of your hand movements. Plus, a higher magnification means a smaller field of view. 

Still, this problem has been addressed in the latest years and some high-power binoculars feature a technology called image stabilization to auto-correct the blurs that occur because of high magnification power and hand movements.

In some cases, a small field of view will affect the entire experience. Think of astronomical purposes, for example. A model that ensures a larger field of view means that you will get to see more of the sky and stars you’re interested in. Still, a too large field of view may lead to image distortion, especially near its edges. 



Magnification power and purpose of use 

As we’ve said before, your specific purposes will help you choose the right magnification power. The most common magnification specs include the ones in which the first number is 5x, 7x, 8x, 10x, and 12x. Binoculars designed for general purposes are usually marked 8 x 42, 7 x 42, or 7 x 50. 

However, if you’re interested in general hunting, for example, you might want to try 7x to 10x power models. For a distant game, 12x or 16x binoculars are usually preferred. In case you’re looking for binoculars that will help you with various outdoor activities such as hiking, models with a magnifying power ranging from 7×35 to 7×50, 8×42, 10×42, 8×30, and 10×30 are a good option. 

8×42 binoculars are usually preferred for bird watching yet if you want to observe details in smaller pieces at a distance, then you might want to try 10×42, 10×50, or 12×50 models. 

Binoculars are not only used for outdoor activities. Indoor concerts and events sometimes also require the use of these optical instruments. If that’s your case, good options include 5×25 or 8×25 models with an extra wide angle. For enhanced comfort, you can also try compact models such as 4×30, 7×18, and 7×21 binoculars. 

For equine and stadium sports, 4×21, 8×25, and 10×25 models are preferred. Still, you could also try 7×35, 10×50, or 12×50 binoculars. For more comfortable use, a compact model from 7x to 10x should be considered. 

If you intend to use the binoculars you want to buy in low light conditions, you might want to try a 7×50, 8×42, or 10×50 model. The 7×50 option comes with great light-gathering specs; therefore, it is worth trying if you tend to prolong your outdoor sessions even when it gets dark. 

The magnifying power ensured by the binoculars you use is of great importance if you want to see distant objects and wildlife in detail yet this specification is not the only that counts. 

Think of the outdoor activities you need binoculars for, the time of the day planned for your activities, the weather conditions, and all the aspects involved since, for example, you might get the right magnification specs but end up with a foggy view because the model you’ve chosen is not fog proof. 



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.

Notify of
Inline Feedbacks
View all comments Protection Status