How To Choose Binoculars

How To Choose Binoculars

Once you’re out in the field, your binoculars become the most important piece of kit you own. The first bird you see through your binoculars, with all the details, colours and other parts of an even common garden bird so defined, you’ll understand just why all expert birders won’t go anywhere without their binoculars. You will also understand exactly why it is so important to choose the correct pair of binoculars, first time.

In all honesty, binoculars are not cheap, well some are, but you need to swerve those as fast as you can. We recommend you invest as much as you can afford in a decent pair of binoculars. The set of binoculars you choose to invest your money in, will last you a good long time as long as you treat them right, and they start earning their keep just as soon as you spot your first bird.

Our advice is to do your research, find out as much as you can, listen to your friends and contemporaries and then save up until you can afford the best binoculars you can get your hands on.

With that said, many years of research and development by top manufacturers has resulted in some lower priced models being pretty good. Some lower priced models are almost as good as top brands, they’re not as good, and you really do get what you pay for with binoculars. We have been in this industry for many years and we could just list a few brands that will be the best you can get for the price, but it is always best for you to make the correct choice and buy the pair that fits right with you.  

How To Choose The Best Pair Of Binoculars To Suit You

There are 2 ways to buy binoculars, and we want you to choose right so you will get the best from your choice. Whichever pair you choose, will be yours for years to come so it pays off in the long run to get it right from the start. So what are the 2 ways to buy binoculars?

  1. Just Buy The First Pair You See Without Doing Any Research At All
    This works out for many people who just want another ornament for the shelf.
  2. Buy The Best Pair Of Binoculars You Can AffordAfter Doing Enough Research
    This way you’ll be investing in years of pleasure watching birds with colours and mannerisms you never knew existed. The correct pair of binoculars will not need upgrading every few years as better products become available. They will last for decades and if you buy them right and look after them, they will be as sharp after 10 years as they were when you first bought them.

Purchasing Binoculars Is Like Buying A New Car

Before you go to buy a new car, if you have any sense at all, you’ll do your research. In fact, you should be so knowledgeable about the car, that the salesman will be asking you questions! Let’s face it, you’re going to lay out a lot of cash, so you should do your research. You should know the engine size, brake horsepower, engine size choices, even what wheel trims are available.

It’s exactly the same with binoculars, as we said earlier, they’re going to last you a lifetime and do exactly what you expect them to do. That’s only possible if you are very lucky, or you do your research. So here are a few of the key facts you need to know before you purchase any binoculars.

How To Buy Binoculars

There are a few basic principles you’re going to need to understand before you go near a binocular seller. So here goes:

What Do The Numbers Mean On Binoculars?

Stamped on the front of most binoculars are the first 2 pieces of information you’re going to need to know. Those numbers tell you the strength of the binoculars (magnification) and the size (objective lens). For example, on a pair of 10X 50 binoculars, the 10 is the magnification and the X is times so 10X means that pair of binoculars has a 10 times magnification. 

The 50 is the diameter (in millimetres) this gives you an idea of how big the binoculars are, and how much light they allow into the lens. Once you get an understanding of these 2 numbers, you will have a far better idea which binoculars you need for whatever you are going to use them for.

So let’s expand on that information straight away, because this really is important.


So the first number and the “X” indicate the magnification, in this case 10X this means you can see an object that’s 10 yards away, 10 times closer, so that means an object 10 yards away seen through a 10X magnification will appear to be 1 yard away. 

Some binoculars will have two numbers shown before the “x”, for example 10-22x, this means that the binoculars have a zoom feature that will allow you to see at magnifications between 10 and 22 times.

That’s a pretty straight forward one to get your head around so let’s move on.

Objective Lens Diameter

The objective lens diameter tells us how much light the binoculars can gather, in this case we had a number of 50 which is pretty high, and with objective lens diameter, the bigger the better. The high number indicates the size of the lens, and the larger the lens, the more light, the clearer, crisper and sharper the image. If there are 2 pairs of binoculars that have the exact same specifications, but one has a higher objective lens diameter, that’s the one with the clearer brighter image.

Field Of View

For certain activities a wider field of view is very useful, bird watching for instance. The wider the field of view the easier it is to scan an area for birds. Plus it makes following birds in flight easier too. 

The higher the magnification is, the lower the field of view is. The field of view is measured as an angle which is usually between 6 degrees and 8 degrees or as a linear measurement. It is measured at how many yards are visible across the diameter of the field at 1,000 yards or how many metres are visible across the diameter of the field at 1,000 metres. It can usually be spotted printed somewhere on the binoculars.

HD Or ED Glass

To combat Chromatic Aberration (CA) which causes a bright colour ring around high-contrast objects through the lenses, top quality binoculars have usually added Flourite to the glass. They then market the binoculars as either Extra-low Dispersion (ED) or High Density (HD) to let you know the lens is of a higher quality and less likely to cause CA or glare.

Binocular Sizing Guide

The size of binoculars you choose will often be determined by the activity you are taking part in. They basically come in 3 sizes and are classified as follows:

  • Compact Binoculars
    Compact binoculars are classified as anything under 30mm (8×25, 10×28 etc)
  • Midsize Binoculars
    Midsize binoculars are classified as anything between 30mm and 40mm (8×32, 10×32 etc)
  • Full-Size Binoculars
    Full-size binoculars are classified as any that have an objective lens of over 40mm (8×42, 10×50 etc)

Compact binoculars are usually lightweight and are handy for fitting in a day pack etc. Midsize binoculars are probably the most comfortable to hold, long-term. With full-size binoculars probably giving you the best viewing power but can become heavy to hold in a short time.

Other Jargon It’s Well Worth Getting Your Head Around

There are other terms that you will hear pop up in relation to binoculars so it’s best to get all the bases covered before you make a decision.

What Does Exit Pupil Mean?

In simple terms, the higher the numeric value the brighter the image. High numbers mean better viewing in low-light. Plus the higher the number, the clearer the image even if you shake a bit. To calculate the exit pupil size you simply divide the objective lens diameter by the magnification number so in our earlier scenario that would be 50 divided by 10 which gives an exit pupil value of 5 mm.

50 ÷ 10 = 5

The average pupil size varies from around 2mm in bright lights to 7mm in total blackout darkness. So 5mm is pretty good for dawn, dusk or dense tree coverage. For bright daylight situations the exit pupil size is not so important because pretty much all binoculars have exit pupil values of over 2mm.

What’s Eye Relief?

This is another one of those terms that sounds so much more complicated than it really is. Basically eye relief is the distance between the eyepiece and your eye whilst the complete field of view is visible. This is an important factor if you wear glasses, and if you do, you want to get an eye relief of 11mm or over. 

Usually the eye relief stated will be the maximum, and to adjust the eyepiece to get to that you either roll down the rubber eye cups or twist the collar to shorten the eyepiece.

Optics And Other Binocular Related Terminology

We’ve covered the basic jargon, now it’s time to get into the lenses and other parts that make up the optical array of the binoculars.

What Are The 2 Prism Types?

The prisms are the way light is directed from the image to your eyes. There are 2 types of prisms used in binoculars and which type you have will determine the size and shape of your binoculars.

The Porro Prism

These are the older type of prisms and have been around since being invented by Ignazio Porro in or around 1850. It works by reflecting the image between 2 prisms but is then shown upside down, so to make it work in binoculars 2 sets of prisms are needed to produce an image the same way up as it actually is. This means the Porro prism is used in bigger sized binoculars.

Roof Prisms

Using roof prisms in binoculars allow them to be more compact, so binoculars with roof prisms will be the straight tube types with just the central hinge. As they are much smaller in size you could be forgiven for assuming they will be considerably less expensive but due to the complicated process for making the internal angled prism, they can be more expensive. As we said at the beginning, you get what you pay for and many roof prism, compact binoculars are far superior in quality to their larger Porro prism counterparts.

What About Protection?

There have been many improvements made over the centuries when it comes to protecting binoculars and that’s what we’re going to go through now.

Rubber Coated Binoculars

This is handy to have if you are going hiking, or anywhere over fairly rough terrain. It won’t prevent all damage, but it will stop minor scratches and abrasions.

Weather-Resistant And Waterproof Binoculars

We’ve included both types in the title because there are some, shall we say confused sellers on some of the big e-commerce platforms that think water-resistant and waterproof are the same thing. This is another one of those buyer beware things, however if you think that a pair of binoculars with night vision, that claim to be waterproof with “fully coated lens” and all for less than £14.00 is a good buy, well we think you’ll be saying goodbye to your money and buying a piece of junk, not even fit for an ornament. Sorry for the rant but honestly- back in the real, serious world of how to choose binoculars…

If you’re going to go marine life watching on board a boat, going out into the ocean, or kayaking or even trekking through the great outdoors in the rain (remember this the UK) then you’re probably going to need some sort of weather protection.

So what’s the difference between waterproof and water-resistant?

  • Water-resistant or weather-resistant
    If they say water-resistant (or weather-resistant) they are not waterproof. Light rain will be fine, but not a heavy downpour and definitely not a full on dunk in the river.
  • Waterproof
    Waterproof binoculars usually use O-rings (rubber washers) to keep moisture out. There are different levels of waterproofing, some are completely waterproof whilst others can handle a short drop in the river. In any case it’s not really a good idea to drop them in the river to test them out. There are some of the top makes that give a lifetime guarantee, but even this will be invalidated if you deliberately chuck them in the river.

Fog-Proof Binoculars

If you move from a cold environment to a warm one, binoculars can fog up making it impossible to see through them. This can be annoying and it can damage the binoculars if there’s moisture trapped inside.

To counteract fogging, binocular manufacturers remove the air from inside the lenses and replace it with nitrogen. As nitrogen has no moisture content, there’s nothing to condense – so no fog.  This only works on the inside of the lenses obviously. You’ll still need to wipe the outside.


This is very much worth due consideration as let’s face it, you’re going to be laying out quite a lot of your hard earned cash. Some companies are better at warranties than others, for instance the Helios brand offer a 5 year limited warranty, Opticron’s warranty appears to vary depending on the product,Leica seem to offer a 3 year passport warranty plus a 10 year defect warranty, Celestron appear to offer a 2 year warranty. Whereas others like Hawke offer a lifetime warranty.

The length of the guarantee is quite important on such precision instruments and should be a major consideration before making a purchase.


How Much Will A Decent Pair Of Binoculars Cost?

You don’t have to spend a lot of money on a pair of binoculars, but you will have to keep spending if you buy cheap ones. Why? Because cheap binoculars live up to their name – Cheap (and nasty). You can expect to pay anywhere from £100 to £1,000 for a pair of last a lifetime binoculars. Or you can keep on buying those cheap ones that mist up, leak, give you double-vision images, need we go on? 

Choosing Binoculars For Specific Tasks

There are certain activities that call for specialist equipment, so we have compiled the following to help you decide which binoculars are best suited to the task.

Bird Watching

If size and weight are not a major concern then mid to full size models will be your best bet. The popular sizes for bird watching are 8X32 and 8X42. You could go with a 10X magnification but 8X will give you a wider field of view, which will be helpful in locating the birds. Having a waterproof pair will be handy and you will probably benefit from some anti-fog lenses too.


Weight will probably be one of your deciding factors for hiking, so your best choice will be something compact. We suggest a magnification of 8X or 10X with an objective lens of around 28 (8X28, 10X28 or maybe lower, 8X25 or 10X25). If you do a bit of rock climbing, consider rubber coated models, and waterproof or resistant might be a good idea too.


As you will be subject to the motion of the water, a lower magnification will give you a steadier view. Maybe 8X or even 6X. A popular size for kayaking is 8×32, and we recommend a waterproof pair too.

Whale Watching

We would suggest 10×32, 10×42, 8×32 or 8×42 if you are not going to get too close to the action, maybe go for 10x. If you want a more compact model, choose 32 rather than 42 lens. Water-resistant or waterproof would be a good idea.


This is the time for maximum magnification and as much light as you can, so we suggest 10×42 or 10×50. If you want to go with any higher magnification you’ll need to consider a tripod for stability.

Frequently Asked Questions

What are the best binoculars for long distance viewing?

You will need a pair of binoculars with a zoom lens, these can go to 22 times normal eyesight. With this sort of magnification it is possible to see the rings of Saturn, but you will need a tripod to stop shaking.

How far can binoculars see?

The human eye is supposed to be able to see for 30 miles on a clear day with no obstacles. With 10×50 binoculars allowing you to see 10 times as far, in theory you can see 300 miles with binoculars.

When were binoculars invented?

Binoculars were invented in 1608, but were not really considered any good until 1825 and perfected in 1849.

Where sells binoculars?

There are many online companies that sell binoculars including us here at binocular base.

Can you get binoculars with night vision?

You can get binoculars with night vision, but be warned, night vision can leave you night blind for a short period of time which can make you vulnerable.