How To Choose Binoculars For Glasses Wearers (Best UK Guide)

The most important thing you need to know if you wear glasses and you’re looking for binoculars is eye relief. There is a whole lot more information that’s equally important but eye relief is top of the list for those of us who wear glasses. According to a recent survey^[1], 59% of the population of the UK wear glasses. More than half the population of the United Kingdom wear glasses, so statistically that’s a lot of people who need to learn about eye relief.

So What Is Eye Relief?

In plain English, eye relief is the ideal distance your eye should be from the eyepiece of the binoculars. So it’s obvious that glasses wearers will need a greater eye relief than non glasses wearers. Poor eye relief has been described in the past as “paying for a front row seat but watching the show from a hole in the fence”. Binoculars with long eye relief are perfectly fine for users without glasses because the eye cups can be adjusted to keep the eyes the correct distance from the lens.

So What Is A Good Eye Relief For Glasses Wearers?

An eye relief with a minimum of 16mm is the starting point for those of us that wear glasses, more is better. Exactly how much eye relief you need depends on how large your glasses are, some people might be OK with 15mm but others might need 19 or 20mm. Manufacturers do print the eye relief value on the box but they’re not always 100% accurate as there are a few ways to measure the eye relief so if at all possible try them on in person. With that said, most of the time the eye relief published is close to the true eye relief.

Most Binoculars Will Compensate For Eye Issues So Try Using Binoculars Without Wearing Your Glasses

What Are Eye Cups?

The eye cup is the piece of rubber or plastic that is attached to the eyepiece of the binoculars. There are two types of eye cups, 

• Plastic Twist Up/Down
• Rubber Retractable

These eye cups can be adjusted to obtain the best eye relief for your eyes. If you do need to keep your glasses on to see the image clearly you’ll need to adjust the eye cup to accommodate your glasses. If you can remove your glasses and use the binoculars in the regular way, you will still need to adjust the eye cups until you can see the image clearly and without any black spots.

What Else Do You Need To Know?

Eye relief is not the only consideration when buying binoculars, there are a few more things that should be considered. Read on for all you need to know before buying binoculars.

What’s The Best Magnification For People That Wear Glasses?

Whether you wear glasses or not, there is a general rule when it comes to the maximum magnification for viewing through binoculars comfortably. You see, we all shake our arms slightly when we hold any item up in front of us for any length of time. But that slight, usually unnoticed shake is magnified when looking through the lens of binoculars.

Any magnification above 10x will show shaky images through binoculars. So the best magnification for glasses wearers or non glasses wearers is between 7x and 10x. Any higher magnification (from 12x to 25x and beyond) and you will need to use a tripod to steady your binoculars.

How Do You Find Out The Magnification Of Binoculars?

Actually printed on the body of the binoculars, you will see a series of numbers, something like;

7×25, 8×32 or 10×42. The first number tells us the magnification value and the x indicates times, so for instance 8×32 indicates that looking through the lens of these binoculars we will see things 8 times closer than they actually are. The second set of numbers indicate the diameter of the objective lens.

What Is The Objective Lens?

The objective lens is the larger lens, the ones closest to the object when you look through the binoculars. In general the larger the objective lens is, the brighter the image is because the large lens allows light to enter. So in our earlier example 8×32, we have a magnification of 8 times and an objective lens diameter of 32mm.

So bigger is better when it comes to objective lens, but…there’s always a but, the larger the objective lens, the heavier the binoculars will be. Which will make a huge impact when holding them for some time.

What Is The Field Of View (FoV)

This term relates to the width of view you can see through the binoculars. Having a wide field of view is an advantage as it makes it easier to locate the object you’re trying to see. This is important when trying to watch fast moving objects like birds for example.  There are two ways the FoV is designated on binoculars, it will either be in degrees or in feet per 1000 yards. 

Something along the lines of say, 6 degrees or 315 feet per 1000 yards (these are both the same), and if the information on the pair of binoculars you’re looking at is only in degrees it’s an easy one to calculate. One degree is equal to 52.5 feet so if for argument’s sake the box says 7 degrees the field of view in feet per 1000 yards is 52.5×7 which equals 367.5 feet per 1000 yards.

What Does Exit Pupil Mean On Binoculars?

The exit pupil is the bright disc you can see through the lens of a pair of binoculars when they’re held in front of you at arms length. This should be greater than the size of your own pupils when they’ve settled down in the dark.

 As an average, a 30 year old usually has a pupil size of 7mm in diameter. This decreases every decade by 1mm so at 40 the pupil size will be 6mm in diameter and so on. An exit pupil of 7mm or more is what’s expected in binoculars, and the higher the better.

Do You Need Lens Coatings?

There are many types of lens coatings available on binoculars and it can be a bit confusing. In principle, lens coatings are a good idea, but some are better than others. The one to look out for is a fully multi-coated lens. This means that all of the lenses have been coated numerous times to reduce glare, increase colour, improve light transmission and brightness.

Is Waterproofing A Good Idea?

As we live in the United Kingdom, at some point you will get caught out by the weather. A bright sunny morning can soon deteriorate into a wet afternoon, and that’s during the Summer. So waterproofing is a good idea when it comes to binoculars, but like lens coatings, there is some confusion when it comes to waterproofing.

Some manufacturers claim their binoculars are “weather resistant” or “water resistant” which effectively tells you very little. So the industry came up with its own code which is in itself somewhat confusing. But suffice it to say that as long as you buy binoculars with an IPX code of 6 or above (IPX6) you will be covered from whatever the British weather can throw at you.

What About Fog Proofing?

Fog proofing is achieved by removing all of the air from the tubes that support the lenses and replacing it with an inert gas. Argon or nitrogen contain no moisture so they will not react to sudden temperature changes like leaving a warm house and standing in a cold garden to catch a view of a comet.

As well as keeping the gases in, the seals used on the binoculars also keep out any dust, mould spores or microbial debris. So it’s well worth considering both waterproofing and fog proofing.

What About Image Stabilising?

Image stabilising technology is courtesy of the camcorder development, and has been incorporated into some binoculars. It detects when an image is shaky and somehow changes it to show it to you as a solid image. This is probably necessary if you are considering buying a pair of binoculars with more than 10x magnification or intend using binoculars whilst travelling.

There are a few disadvantages to image stabilising in binoculars, the batteries need regularly changing and it makes the binoculars heavier.

Do You Need A Protective Casing On Your Binoculars?

If you are accident prone, it’s well worth considering a pair of rubber coated binoculars as these will protect your valuable investment from damage. Especially if you intend hill walking or rock climbing. Or even if you just enjoy travelling and want to protect your binoculars from bumps and scrapes.

Which Type Of Binoculars Are Best?

There are two types of binoculars, both with their good and bad points, so let’s explore both so you can make an informed choice on which type suits you best. They are;

Porro Prism Binoculars

Porro prisms take their name from their inventor Ignazzio Porro who developed this type of binoculars back in the 1850s. They are the classic M shape binoculars with their small eye piece leading down to the wide central part where the prism set up is housed. Then on down to the wide objective lens. 

Due to the prism set up, this type of binoculars are damaged fairly easily, but are also relatively cheap compared to roof prism binoculars. Porro prisms have two angled prisms that reflect the image, magnify it and return it to its original way up. This is why they are larger by design and easy to knock out of alignment. 

Roof Prism Binoculars

Roof prism binoculars are compact, lightweight and smaller than Porro prism binoculars. They are shaped much like a H with the two thin tubes separated and joined by the central focusing knob. The prisms are set in the roof to magnify and transmit the image to the eye piece. 

Roof prism binoculars fall into two types, cheap and not very good and exceptionally good but relatively expensive. They do seem to be the more dominant type of binoculars currently. They are discrete and easy to carry as well as being powerful.

To Sum Up The Pros And Cons Of Both Types OF Binoculars

Roof prisms are smaller, lighter, but a decent pair will set you back much more than a comparable Porro prism pair.

Porro prisms are heavier, larger and easier to knock out of alignment which will cause eye strain, headaches and migraines. But they are less pricey than roof prisms.

How Much Will A Pair Of Binoculars Suitable For People That Wear Glasses Cost?

In all honesty you can pick up a pair of binoculars for around £15.00 but they will not be much good. A decent pair will set you back anywhere from £150 to £1000 but anywhere around the £200 to £250 range will be adequate for most activities.

Frequently Asked Questions