How To Choose Binoculars For Long Distance Use (Best UK Guide)
If you’re planning to buy binoculars for long distance use, and are not sure what you need in a pair of long distance viewing binoculars well done. You found this article which means you’re serious about your intentions. We can help you to make the best choices for a really decent pair of long distance use binoculars without falling into any of the advertising and marketing hype that’s intended purpose is to sell you that company’s particular types of binoculars.
Binocular Base is here to sell binoculars, of course we are, but we want you to be 100% happy with the pair of lenses you choose. To that end, we’ve put together a series of buyers guides for binoculars to suit any occasion. To guide you through all of the confusing terminology, various sizes, features and translate scientific optical language into plain English.
So let’s jump straight in with a question, why do you need binoculars for long distance viewing? It might sound like a stupid question, but our needs don’t always meet our intentions.
Table of Contents
Why Buy Binoculars For Long Distance Use?
In an attempt to answer our own question, binoculars for long distance use are pretty specific in their usage. For instance if you’re planning on hiking, backpacking or just a general walk about and would like to get the most from your time outdoors, a pair of binoculars will enhance your pleasure and help you see many objects close up, from a distance. But you wouldn’t necessarily need long distance binoculars which will be larger and heavier than a smaller pair with more applications.
So before we get into the best options for binoculars for long distance use, let’s have a look at what they will be best suited for. Binoculars for long distance use are the best choice for;
- Watching Migratory Birds
- Sports Hunting
- Wildlife Viewing
All done from a pretty much stationary position because a decent pair of binoculars for long distance use will be relatively heavy, with high magnification. Any magnification higher than 10x, will cause the image to appear with a slight blur, because we all shake slightly when holding heavy objects out in front of us for extended periods of time. Now under normal conditions that shaking’s not a problem and probably unnoticeable.
However, through the lens of a 12x binoculars, that shake is magnified 12 times, so a slight shake becomes a huge problem when trying to focus on a single object some distance away. Hand held binoculars are fine up to and including 10x magnification, anything above 10x (12x, 15x, and so on) need to be placed on a tripod to keep the image completely stable. That’s why we question whether you need binoculars for long distance or whether a smaller, lighter pair might suit you better.
But that’s enough questions about your intended usage, let’s get into what you need to look for to get the best binoculars for long distance usage you can at your budget.
What Are The Benefits Of Binoculars For Long Distance?
There are many benefits for buying binoculars for long distance use, as long as you invest wisely. The main benefits include;
- Being Able To see Objects From A Long Distance Clearly
- The Ability To Withstand Dropping From A High Distance
- Often Made From High-Grade Materials As Used By The Military
- Relatively Easy To Use
- The Ability To Withstand Extreme Weather Conditions
- Constructed From Extremely Strong Yet Lightweight Materials
- Great For Many Activities Including Stargazing, Bird Watching, Hunting, And More
Different Types Of Binoculars For Long Distance Use
There are three main types of binoculars made for long distance use. They all offer their own advantages and features and this will be the first choice you’re going to need to make on your quest for long distance bins. They are;
Aluminium binoculars are usually the lightest, and least expensive option for long distance optics. Aluminium binoculars are pretty durable, weather resistant and reliable. Aluminium is a corrosion and rust resistant material and as it’s lightweight the binoculars will be lightweight, and easy to carry, for camping, hiking, or bird watching trips.
Polycarbonate binoculars are slightly more pricey, but they’re also slightly more durable and higher quality than aluminium. Polycarbonate is also resistant to temperature changes and can take extremes of heat and cold. The polycarbonate structure is designed to protect your lenses during these extreme conditions too. If you’re planning on using your long distance binoculars under extreme weather conditions, polycarbonate binoculars will be a good choice.
Magnesium binoculars are the most expensively priced, but they are extremely rugged, and strong, and often used for tactical purposes. If they get accidentally dropped, they’re less likely to get damaged and they can be used underwater (to a certain degree). Magnesium binoculars will cost more than either of the other two, but they’re also lightweight, portable and strong.
Which Design Of Binoculars Are Best For Long Distance Viewing?
There are two main binocular designs and they both have advantages and disadvantages when it comes to long distance use. Let’s have a quick look at both types.
Porro Prism Binoculars
The basic design of Porro prism binoculars has been around for centuries and is probably the image that first comes into your mind when thinking of binoculars. Shaped like a capital M or an inverted W, Porro prisms are narrow at the top, where the eyepieces are. They become far wider and larger in the midsection (due to the offset prism arrangement) and become even larger at the bottom where the objective lens are housed.
Roof Prism Binoculars
Roof prism binoculars are shaped like a capital H – Two straight tubes joined in the middle by the focussing wheel. There are no offset prisms used in these, the prisms are housed in the roof of each lens tube. This arrangement makes them smaller, lighter, easier to carry, easier to waterproof and easier to conceal. But all of the precision components and the processes needed to construct roof prism binoculars does mean they are significantly more expensive than the equivalent Porro prism.
The Pros And Cons Of Porro Prism Binoculars
|Benefits of Porro Prism Binoculars||Disadvantages of Porro Prism Binoculars|
|Wide spaced Objective lens||Big, bulky design|
|Better stereoscopic images||Heavy|
|Cheaper to produce||More internal parts (more likely to go wrong)|
|Harder to waterproof|
The Pros And Cons Of Roof Prism Binoculars
|Benefits of Roof Prism Binoculars||Disadvantages of Roof Prism Binoculars|
|Compact design (smaller, lighter, less bulky)||More precision components=more expense|
|Less internal parts||Some cheaper models are of inferior quality|
|Easier to waterproof and dust proof|
What Do The Numbers On Binoculars Mean?
Stamped on to the body of the binoculars, you will find a series of numbers separated by the letter X. These indicate the level of magnification and the diameter of the objective lens. So 10×50 indicates a magnification of 10 times (the X represents times) which means that everything you see through the binocular lens will be 10 times larger than seen through the naked eye.
The second set of numbers indicate the diameter of the objective lens in millimeters (in this case 50mm). The objective lens diameter is important because it determines how much light can enter the binoculars to illuminate the image you can see through the lens. The objective lens diameter also determines the sizing of the binoculars, there are three sizes for binoculars and they are as follows;
- Compact Binoculars – Objective lens diameter below 30mm
- Mid Size Binoculars – Objective lens diameter between 30 to 40mm
- Full Size Binoculars – Objective lens greater than 40mm
As the objective lens size increases, so does the overall weight of the binoculars. So the larger the objective lens diameter, the brighter the image will appear through the binoculars, and the heavier the binoculars will be too.
The magnification level affects how far you can see, and how much detail you will be able to see. The magnification also affects the field of view.
What Is The Field Of View?
The field of view (FoV) refers to the width you can see through the binocular lens from left to right whilst looking straight ahead. It is usually expressed in one of two ways, either as an angle (angular FoV) or as so many metres per 1,000 metres (linear FoV). The higher the magnification, the narrower the field of view.
To get a wide field of view at a high magnification requires powerful optics which cost far more to produce. So generally the FoV narrows as the magnification increases.
This is the size of the circle of light that hits your eye through the binocular lens. For perfect viewing, the exit pupil should be greater in size than your own pupil. This is because the more light that hits your eyes will create a brighter, clearer image.
You can calculate the exit pupil of binoculars by dividing the objective lens diameter by the magnification. For example our earlier binocular size of 10×50 would have an exit pupil of 5mm because 50÷10=5. The average size of the human pupil is around 7mm at the age of 30 and decreases by one millimeter every decade, so at 40 the pupil will be 6mm and so on, this all settles down at around the age of 80 when the pupil size is around 2.5mm.
So as we age we will need a smaller exit pupil on our binoculars, but too much is always better than not enough when it comes to exit pupil size.
Variable Magnification (Zoom Lens) Binoculars
Variable magnification would appear on the binocular body as something like 20-30×60, which would mean a 20x magnification that can zoom to 30x magnification with an objective lens diameter of 60mm. Zoom lenses appear to be a good idea because you’ll be able to see objects much closer than they appear (up to 30 times closer) but the reality is low image quality and hazy views.
There are not many of the top brands that produce zoom lens binoculars and the ones that do, don’t go above 24x probably because of the poor image quality.
Low Light Binoculars
If you are going to use long distance binoculars you will need the highest light transmission levels possible. This will make your long distance objects appear bright enough to see clearly and appear lifelike as well. This is true unless all you plan to do is stargazing, in which case regular light transmission and magnification size will work just fine.
The Weight Of Long Distance Binoculars
Due to the objective lens diameter and the increased magnification needed for long distance viewing, the binoculars will be quite heavy and often quite large too. Shaky images aside, holding heavy binoculars for extended periods of time can be quite exhausting and take the pleasure out of using binoculars. Most long distance binoculars come with the option of a tripod adapter. This will allow you to look at the subject that interests you for a long period of time without experiencing fatigue or a shaky image.
To compensate for a shaky image at high magnification, some binocular manufacturers have introduced Image Stabilisers to some of their models. The technology comes directly from the camcorder industry and detects any instability in the image and corrects it automatically.
There are a few drawbacks with IS for a start; it adds weight to already heavy binoculars due to the on board batteries, and the batteries will need to be recharged or replaced (depending on the model) at regular intervals.
Binocular Body Armour
To protect your high powered investment, most of the top binocular brands coat their binoculars in a protective rubber or polycarbonate coating. This will stop any bumps or scrapes should you drop your binoculars or collide with concrete fence posts or rock faces. The coating also makes the binoculars easier to grip even in wet conditions.
Waterproof & Fog Proof Binoculars
Whilst on the subject of the weather, living as we do in the UK, it is inevitable that at some point the weather will catch you out. Once rain water gets into your binoculars they will never be the same again. To prevent any weather related damage it’s best practise to be sure your binoculars are waterproof.
There are many levels of waterproofing for binoculars with some unscrupulous traders claiming all sorts of things. So the industry set up its own coding system to remove all of the confusion on waterproofing. Unfortunately that coding can make for confusing reading itself, so just remember that binoculars with a IPX6 or above will be capable of withstanding anything the Great British weather can send your way.
To prevent binoculars from steaming up when changing from hot to cold temperature, the manufacturers remove the air from the lens tubes and replace it with either nitrogen or argon. As these types of gas contain no moisture, they cannot react to sudden temperature fluctuations, and won’t fog up.
Once the gas is sealed into the lens tubes, no gas can escape, and no dust can enter either. This can be very useful because dust is not the only thing kept out. Mould spores cannot enter either which means no nasty internal growth partially blocking your view.
Just like waterproofing, there are many different types of lens coatings, all are anti-reflective but amounts can vary. So if you can, you should go for fully multi-coated lens coatings as these cover the lenses inside and out in multiple coats of anti-reflective coatings. Fully multi-coated lens coatings are able to offer more than 90% light transmission.
All of the glass used to make the prisms and the lenses for binoculars needs to be high on the refractive glass index. This allows better levels of light transmission, which in turn, means clearer brighter images with no haloing.
BAK4 is the best optical glass used in top quality binoculars, closely followed by BK7 which has slightly more imperfections in the glass and is slightly less refractive. Both are top optical types of glass but premium binoculars use BAK4.
Extra low dispersion glass is used on many of the best quality binoculars. This is specially formulated glass that keeps colours bright and clear, and prevents chromatic aberration. Chromatic aberration causes the colours in an image to not combine as they should. ED glass prevents this from happening, giving you the very best image possible.
What Is Eye Relief?
The eye relief is the distance between the eyepiece and your eye where you can still see the full field of view. It will be quoted in the binocular specs in millimeters. Typical eye relief on binoculars is anywhere between 12 and 16mm. If you need to wear glasses, you will need to look for binoculars with what’s called long eye relief, which is anywhere between 16 to 24mm, and allows room for your glasses while still seeing the full field of view.
If you only need glasses to correct your vision for slight long or short sightedness, it will be possible to remove your glasses and adjust the focus on the binoculars to account for your eye condition.
These are usually made from either rubber or soft plastic, and are the part that touches the face around the eye when looking through binoculars. They can be adjusted by either twisting them up/down or folding up/down. Eyecups allow you more space to accommodate your glasses but do not accommodate enough for some glasses wearers and that’s where long eye relief comes in.
Long Distance Binoculars Vs Spotting Scope
If you compare a spotting scope with long distance binoculars, a spotting scope will win every time when it comes to magnification. The zoom on a spotting scope works exceptionally well whereas zoom binoculars as we said earlier often leave plenty to desire. There are compact spotting scopes that will weigh around the same as a pair of high powered binoculars. With the advantage of the extra magnification of a scope.
If you are looking for a higher magnification than 20x then a spotting scope will definitely suit you better. Spotting scopes have far higher magnification and objective lens diameters than binoculars, but you can’t get stereoscopic vision with a spotting scope.
Also binoculars will always have a wider field of view than a spotting scope (due to double the lens capacity). Spotting scopes will almost always need a tripod unless you go for such a low magnification that you’ll be better off with binoculars anyway.
Frequently Asked Questions
This depends on whether you plan to hold the binoculars in your hand or use a tripod. For hand held we would recommend 10×50, for tripod use maybe 20×50 would probably be the best.
You do need a tripod with any binoculars above 10x magnification to reduce the natural shake that we all have, but becomes noticeable above 10x mag.