How to select the right magnification for your binoculars

Hunting for the perfect pair of binoculars for birdwatching, stargazing, or any other outdoor activity? You’re in luck!

In this guide, we’ll show you exactly how to select the right magnification for your binoculars. We’ll also explain why this is important and provide tips to ensure you make the best choice.

So if you’re ready to take your outdoor experience to the next level, let’s get started!


Firstly, you need to decide your primary use of the binoculars. This will help determine which optical features and performance levels you will require. A clear distinction must also be made between binoculaurs that are suited for daytime, astronomy and general/military use.

Since binoculars do not have a single, standardized magnification level (like microscopes) it is important to understand how magnification works in order to make an informed selection when purchasing a pair of binoculars. To get a better understanding of the various magnifications offered by different binomarl models and their applicability to different fields of view and requirements, we have put together this complete guide on how to select the right magnification for your purposes.

Importance of binoculars in birdwatching

Binoculars are essential tools for birdwatchers, nature lovers and adventurers alike. They enable you to get closer to the action – providing you with a better view of the animals in their natural habitat and better appreciation of the terrain around you. However, choosing the right binoculars can be tricky as there are many factors to consider such as type of magnification, type of lens, field-of-view and size.

When selecting your binoculars it is important to consider how they will be used. Birds are generally active during daylight hours so it is important to invest in binoculars that provide good clarity during low light conditions. High quality optics help boost clarity and brightness which may help you spot birds which may otherwise remain unseen in shadows or foliage cover.

The most important thing to consider when buying binoculars is the magnification levels because this affects both image resolution and field-of-view size. Generally speaking, higher magnification means larger field-of-view sizes however this comes at the cost of reduced brightness due to less light passing through the lenses. It is therefore generally recommended that birdwatching binoculars should have a magnification of between 7x and 10x with an objective lens size range between 42mm and 52mm for maximum performance.

Overall, when selecting binoculars for birdwatching it is important to consider inherent properties such as image resolution, field-of-view size, optical construction quality and build quality – all of which will help determine how successful your adventures will be when searching for birds in their natural habitat!

Overview of the guide

This guide will provide an overview of the different types of binoculars available on today’s market and explain some of the key factors which should be taken into account when choosing the right binoculars. We’ll look at the many variables that have a bearing on which magnification you should select, before summing things up by walking you through the individual steps needed to select the right set of binoculars for your specific needs.

It’s essential to have a basic knowledge of binocular magnification before selecting a particular model or type as this is one of the most important factors influencing your choice. Knowing how magnification affects image quality, including brightness and clarity, will help you to decide what level is most suitable for you. Magnification, also known as ‘power’, is represented in two numbers: for example, 7×35 or 10×50 are common magnifications used in bins manufactured today – 7X being seven times magnified more than through an unaided eye and 50 (or 35) being their objective lens diameter measurement in millimeters). The higher values indicate increased magnifying powers creating greater clarity and detail in your view. It’s worth noting that an increase in power comes with a smaller field-of-view [FOV] – i.e., with higher magnification the objects within that view become bigger but fewer appear within it; conversely lower power gives wider FOV but makes details appear smaller.

Understanding binocular specifications

Binocular ratings and specifications can be confusing. When you’re trying to decide which binoculars to buy, it’s helpful to understand the different ratings and how they affect the performance of your optics.

Magnification – Binoculars are rated for their magnification power, or “X-power”—this means that whatever object you’re looking at will appear a certain number of times larger than it would with the naked eye. For example, a set of 10x binoculars will make an object look 10 times bigger than it would without them. Magnification is important if you plan on looking at faraway subjects; higher magnification allows for more detail but also makes image stabilization more difficult.

Objective Diameter (Lens) – This specification tells you the size of lenses in millimeters. The lenses collect light and increase the brightness of images seen through the binoculars — making them good for viewing objects in low-light situations like dawn or dusk. A larger lens also increases depth of field, meaning there’s more to focus on at once; however, binoculars with large objective lenses tend to be bulkier and heavier.

Exit Pupil -This number is calculated by dividing the objective (lens) diameter by the magnifying power — so if your 10x40mm binoculars have an exit pupil of 4mm this means that when held 12 inches away from your face, a circle 4mm wide will still be illuminated from your subjects through both lenses simultaneously!

Field of View – This describes how large an area one could view through a pair of binoculars at 1,000 yards away; typically this is represented as feet per 1,000 yards or degrees per 1,000 yards (degrees are unitless). Generally speaking, lower magnifications have wider fields-of-view so they can take in more scenery versus higher magnifications that bring distant objects closer but may still require panning around in order to see all parts of a scene out doors!

Magnification power

The first and most obvious factor to consider when selecting a pair of binoculars is the magnification power. Magnification is typically expressed in a two-number ratio– for example, 8×42. The first number indicates the magnification power of the binoculars — how much bigger it makes the distant object appear versus how you can see it with your naked eye. Higher magnification power will allow you to observe extremely distant objects as if they were much closer; however, magnifications over 10x can be difficult to use and often result in shaky images due to hand movements or windy conditions.

For applications such as bird watching or ocean views, lower magnifications (between 7x and 8x) are recommended to achieve a better field of view with increased stability throughout the viewing session.

Objective lens size

The size of the objective lenses depicted in binoculars is measured in millimeters (mm). This refers to the diameter of each external lens, at the furthest point from the user, and ultimately determines how much light can enter through the lenses.

When choosing magnification strength and optical quality, bear in mind that bigger isn’t always better —at least not when it comes to binoculars! Smaller lens sizes offer excellent optical performance for hunting or birdwatching and are lighter than larger lenses. Larger objective lenses will result in a heavier product but may increase light transmission, allowing you to pick up more details without needing bulky magnifications.

In order to find a balance between image quality and lightweight products that you can comfortably carry around with you for extended periods of time, aim for an objective lens size between 25-42 mm.

Field of view

Field of view (FOV) is the width of space you can see at a given distance. It’s expressed in linear or angular measurement. Angular measurement looks like this: A binocular with a field of view marked 8° means that if you look through the lenses, whatever you’re looking at appears 8° wide. Linear measurements tell you how wide an area 1000 meters away will appear; using the same pair of binoculars, 8m translates to a viewing width of about 8 meters per 1000 meters out.

Don’t leave the store without ensuring your chosen pair offers an adequate field of view for your needs — wider is always better. Wider fields are especially helpful for tracking things like birds and animals in motion, or sweeping landscapes like when searching for distant landmarks. Magnification has the greatest influence on FOV — higher magnification means narrower FOV and lower magnification gives broader FOV — so be sure to look at both when making your selection.

Exit pupil

Exit pupil is the size of the light beam produced by the binoculars that actually enters the individual’s eyes through the eyepiece lenses. Exit pupil size is determined by dividing the diameter of an objective lens with that of an eyepiece lens. The ideal exit pupil size should be two millimeters in diameter and can range anywhere from 0.5 to 7mm.

It is important to choose a binocular with an appropriate, matching exit pupil size based upon one’s age and lighting conditions; this ensures the maximum resolution (i.e., image clarity). For example, younger individuals tend to need binoculars with a larger exit pupil than older users since younger people have naturally dilated pupils that can absorb more light from a larger exit aperture (2-7mm). Older individuals typically require smaller exit pupils due to their reduced ability to absorb light due to smaller pupil sizes (0.5-4mm).

Furthermore, for lower light situations such as dawn or dusk activities, larger pupils are beneficial in order for more light to reach your eye receiving improved image resolution and brightness compared to smaller exits pupils in brighter daytime conditions.

Prism type

The two main types of prism used in binoculars are Rectangular (Roof) prisms, and Porro prisms. Porro prisms align the optical path in a slightly zigzag pattern, which gives the binoculars their distinctive external shape.

Compared to roof-prism designs, Porro-prism binoculars typically have a wider field of view due to the large distance between objective lenses. Roof prism binoculars have sharply rectilinear external form and offer increased durability over porro prism models as well as better ergonomics.

Although recent advancements in material and design technology can often reduce the difference in quality between porro and roof-prism binoculars, some people still prefer one type over the other – it largely comes down to personal preference. Roof-prism models may cost slightly more than porro prism designs, however this is not always the case depending on what type of optics you require for your needs.

III. Binocular designs

When reviewing the different types of binoculars available, it’s important to consider the characteristics of each type and what is most suitable for your intended activity. Binoculars come in a wide range of designs and sizes, from small opera binoculars, through medium sized general purpose glasses, to large astronomical telescopes. Each design has its advantages and disadvantages; when selecting a pair it is essential that you find the type which best suits your purposes.

Below are descriptions of some common binocular designs along with their benefits.

Roof prism binoculars: These have straight barrels where the objective lenses (the furthest from your eyes) are aligned with the eyepieces (closest to your eyes). Roof prism design minimizes optical reflections resulting in clearer images than Porro prism models while being more compact and lightweight.

Porro prism binoculars: These feature angled prisms inside that create an offset between objectives and eyepieces resulting in non-parallel tube alignment. Porro binoculars tend to be larger than roof prism models but offer a wider field of view due to their greater depth.

Compact pocket models: Binoculars designed specifically for pocket sized portability feature smaller lenses usually not exceeding 15mm in diameter along with shorter tubes making them easier to carry or transport on a belt etc. Due to their small size they typically have poorer image quality compared to full-sized models but are ideal for casual viewing or surveillance purposes where mobility is important.

Roof prism binoculars

Roof prism binoculars are named for their shape and design. They are easily distinguished by their straight sides and the sharp right angle where the objectives join the eyepiece lenses. The structural design of the roof prism binoculars is efficient and the light that is captured through the objective lens travels in a straight line. This means that there will be less image distortion, allowing for clearer views at higher magnifications.

The ideal magnification of a roof-prism binocular depends on what you plan to use it for. Magnification isn’t necessarily an indication of overall performance or quality — it’s simply a measure of how large an object will appear when it is viewed through a set of binoculars. For general use, 8x or 10x magnification should suffice, while for long-distance viewing or bird watching, higher magnifications can be used such as 12x or 15x. Generally speaking, bigger bins provide exactly that – bigger images – with clearer details when zoomed in on distant subjects!

Porro prism binoculars

Porro prism binoculars feature offset lenses and prisms, which gives them their characteristic Z-shaped design. These binoculars offer an excellent depth of field with greater clarity in low light. They can also be less expensive than roof prism binoculars and are perfect for extended viewing.

When choosing a magnification for Porro prism binoculars, consider the environment in which you plan to use them. Lower magnifications of 7x or 8x are perfect for close-up or general area viewing in open spaces, while higher magnifications of 10x to 12x work best on targets far away or in heavily wooded areas. As a rule of thumb, 10x magnifications are ideal for hunters who often hunt over uneven terrain and have difficulty locking onto small game at great distances. Probable users should always choose the lowest magnification possible to minimize optical distortions and maximize the field of view needed for tracking wildlife on the move.


The type of binoculars you need depends on your preferences and the purpose of your purchase. Hopefully, this guide has provided you with the knowledge you need to make an informed decision about which type of binocular to purchase. In general, any product in the 8x up to 10x range is suitable for most outdoor activities, although more specialized binoculars may be required for birdwatching or observing astronomy.

Additionally, it’s important to understand the features associated with each magnification level so that you can buy a pair that best suits your needs. Finally, never forget comfort and quality when purchasing binoculars—ensure that your optics have an ergonomic design that won’t cause hand strain after prolonged use and always choose a high-quality brand or manufacturer for the best result possible.

With this guide in hand, you should now be ready to select the perfect Magnification level for your binoculars!

Recap of important factors

Choosing binoculars is a subjective decision, and there are many factors to consider such as eye relief, construction quality, field of view, weight and ergonomics. To help you make an informed choice, here we will recap the important factors when deciding on the right magnification for your binoculars.

Eye Relief: Eye relief determines how easily your eyes can access the full field of view when using the binoculars. Generally, lenses with higher magnifications will have shorter eye relief.

Construction Quality: Lenses with higher magnifications come at a cost – both financially and in terms of durability; high power lenses are more prone to moisture damage and other problems due to their delicate construction. As such it’s important to ensure you buy from a reliable supplier who can guarantee quality products.

Field of View: Binoculars with higher magnifications offer a narrower field of view compared to those with lower magnifications making it more difficult to take in all the details at once. The wider the field of view means that it’ll be easier for you to identify objects that are far away or close by providing greater detail than one with a smaller field of vision would allow.

Weight: Weight is also an important factor when considering what magnification you need as heavier optics can cause strain on your neck if used over an extended period of time and may also affect image clarity in low light conditions as even slight movement can be enough to blur details due to its increased sensitivity.

Ergonomics: Furthermore, depending on how comfortable or uncomfortable you find handling heavier optics this too can influence what magnification is suitable for you; if hand-held observation is difficult then it’ll be best not try too high in terms of magnification as this’ll only further hinder your viewing experience due its heavier weight and reduced stability from tripod use or other mounting equipment.

Final recommendations for choosing the best binoculars

When it comes to choosing the right binoculars, there is no one-size-fits-all solution. The right binoculars for you depend on your budget and activities, as well as considerations such as your eyesight, environment and age. As a general rule, the higher the quality of construction and the higher the magnification, the better. It’s best to start with a pair of quality binoculars that will last a long time without deteriorating in performance over time.

After selecting quality binoculars that fit your needs, you should determine what magnification level is ideal for you. Ideally, you want a magnification level that will provide maximum detail while still allowing you to track an object in motion like birds or animals. For wildlife and birding observation 7x or 8x is ideal since this offers good detail with sufficient field of view and depth of field making it easier to locate animals quickly when they move from one position to another in distance. If you observe ocean life or astronomy events like star gazing, then about 10x would be ideal for viewing maximum details with wide field of view with minimum shakiness even though this comes at cost of portability due its larger size than usual binoculars but more enjoyable experience without compromising clarity unlike lower powered ones while observing far away objects such as stars or solar system bodies.

For sporting events such as golf tournaments or hiking journeys where one may need wider field view than eagle eye clarity in target details then 6×35 is most preferably suited choice lenses which can bring closest focus on items: greater than 17ft away while providing crisp clear picture even up to 47ft away which makes it perfect choice over other magnifications available on market today!

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