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Making the right choice can be difficult. I hope the following will help.

What is the difference between a binocular and a telescope?

1. Weight . Telescopes tend to be heavier - 1 to 2 kilos

A Compact binocular can be as little as 80 gms or 3 ozs

2. Size . Because telescopes are usually more powerful they need a bigger front lens to collect enough light,

so even though a telescope has a single barrel, it is likely to be bigger than a binocular.

3. Magnification or Power. Binoculars can have as little as 4x or 5x magnification. It is possible to hand hold up to 12x.

Above this, you will need to steady the binocular or telescope on a tripod or a clamp to stop the image dancing around too much.

A very high power zoom model really needs a large front lens but the compact versions can be fun.

A telescope eyepiece is likely to be at least 12x or 15x and popular zoom eyepieces are up to 45x or 60x.

These do need a tripod and will also need to have a front lens of at least 60 mm diameter to get a decent image in poor light.

A 50mm front lens will mean a lighter weight instrument that will be perfectly fine in reasonable light conditions.

4. Close focus. Generally the lower the magnification, the nearer you can focus - perhaps 4 to 5 feet with a binocular

but 15 to 20 feet with a telescope.

5. Depth of Field or range of acceptable focus. Binoculars with their twin eyepieces allow you to retain your normal 3D vision

and objects that are in front of and also behind the actual plane of focus, appear acceptably sharp.

Telescopes need to be more accurately focused because they don't have this 3D effect

and their higher magnification reduces the depth of focus.

6. Field of View. Lower power optics generally cover a wider view from left to right.

Very useful when trying to follow a moving object that is not miles away.

7. Image Quality. Both binoculars and telescopes can be made to a price so you can get low or high quality in either.

But you do not have to pay a King's Ransom for a really decent instrument.

Modern £100 to £200 binoculars are as good as the very expensive binocular of 10 to 15 years ago.

8. Design.   A purely personal decision. Porro prism or Roof prism. Both do much the same job .

Roof prisms are more expensive to produce but can be more rugged and need to have:-

Phase Correction Coatings to give as good an image as Porro prism models.

Porro prism models tend to have a wider distance between their front lenses that will give a greater 3D effect.

Roof prisms cost more to make so Pound for Pound ( or Euro for Euro ) you get more porro prism bino for your money.

9. Outer Covering . Rubber covered binoculars can be nicer to handle and don't get so hot in summer or so cold in winter.

Rubber covers do not mean the instrument is water proof. Many models are not.

Another warning about “waterproof”. There are different degrees of waterproofing.

Binoculars made for the Military have a very high spec including the highest level of sealing against water.

Other models can be claimed to be waterproof but for only 5 minutes and to only 1 meter.

Some are weather-resistant, others are splash-proof.

COMPACT binoculars are small enough to slip into a shirt pocket and normally come with a pouch case that can be worn on your belt.

They are light weight so can be taken with you no matter what the activity.

Magnification is usually 8x or 10x but they can have 4 or 5x and up to 12 or even 16x.

There are zoom models that can change their magnification from 6x to 70x.

The light weight is achieved by having small front lenses usually between 20 and 25 mm in diameter

(a 10 p coin has a 25 mm diameter) but as the size of the front lens determines the light gathering ability,

these small front lenses are fine until the light starts to fade.

That is why the classic yachting binocular is 7x 50 which collects the maximum light

and passes it into your wide open eyes when you are trying to find your way into a harbour late in the evening.

A 7x50 is much heavier but you would not wear it round your neck for hours on end.

Increased magnification does not mean increased weight.

SLIGHTLY larger binoculars will have the same range of magnification as compacts

but the front lenses will be 30 or 32 mm.

The weight will increase a bit but the larger lenses will let in more light.

This principle also applies to the LARGER models such as the popular bird watching binoculars 8x40 or 8x42

and the 10x40 or 10x42. These are still not too heavy nor too bulky.

They are brighter when the light level is low and you may find them easier to hold than a compact, as there is more to get hold of.

They won't bring the objects any closer than a compact as that is caused by the magnification.

As a general-purpose instrument, it is worth considering a zoom model 8-24x50,

which can be altered quickly from 8x all the way through to 24x.

The optical quality can be very good indeed and some very good manufacturers include zoom models

in their range of products. Beware that some people are highly vocal against zoom binoculars.

They are often perversely enthusiastic about zoom eyepieces for telescopes.

We feel that a good zoom binocular can be a delight to use and if the light level is low,

you can leave the zoom setting on 8x and not miss anything but the recent trend towards mega zooms is unfortunate.

Compacts with a zoom up to 70x on a 25 mm front lens are fun but……...

COMFORT. You should pick up a binocular and find it a comfortable fit in your hands.

Even the most expensive model may not fit. If it doesn't, then simply pass it by.

Then there is the distance between the two eyepieces.

Binoculars are two small telescopes joined together and until about 1890

when someone invented a way to hold them together so they could be bent to fit different size faces,

our ancestors had to use just one telescope at a time.

Getting the bend right is important. Get it wrong and you will have shadows each side or in the middle of your view.

Some binoculars do not bend close enough for some people and others don't bend far enough apart.

We recommend you bend the binocular as wide as possible and slowly bring the two eyepieces in towards each other.

When the shadow in the middle disappears, that is the correct distance for you.

Technically it is called the Inter Pupillary Distance or IPD and you should make a note

of your distance in case some one borrows your binocular and sets it differently.

Another important distance is the one called Eye Relief.

This is the distance from the eye lens of the binocular to your eye lens.

Important if you wear spectacles and leave them on when using a binocular.

It is easier to leave your specs on, so a binocular to suit you must have a sufficiently long eye relief

that you do not lose a significant amount of the left to right field of view.

Roll down rubber eyecups or the latest retractable / twist up cups allow most

if not all of the field of view to be retained and help reduce scratches on your spectacles.

CLOSE FOCUS. The general rule is that as you increase the magnification,

the close focus distance moves away from you and the field of view decreases.

For example Bushnell Natureview 8x42 Field of view 114 m @ 1000. Close focus 3m

                    Bushnell Natureview 10x42 Field of view 107 m @ 1000. Close focus 4m

                    Bresser Saturn           15x60 Field of view   76 m @ 1000. Close focus 8m

WATERPROOF. Do you need a waterproof binocular or telescope?

Hunting, Fishing, Sailing, Boating, Deer Stalking - yes you do unless you take really good care

but waterproofing costs more. Rubber armoured binoculars are not necessarily water proof

or even water resistant. Expensive models are often completely sealed so they are waterproof

and dust / sand proof. Less expensive models have gaps so moisture / dust / sand can get in.

You would not believe some of the things that we remove from inside binoculars

including spiders with webs; grass seeds; small beetles and enough sand to build a small castle.


One is the Zeiss or European style. A wide body with the front lens in a cone offset from the eyepiece.

Another is the Bausch & Lomb or American style where the body is one piece

but the front lens is still offset from the eyepiece.

The third is the Roof prism style that looks like two tubes, often slimmer at the eyepiece, getting wider at the front lens.

All three produce the same result. Light enters at the front, bends around / through the prisms

(otherwise you would have a telescope) and leaves by the eyepieces.

The first two styles are less expensive to produce and less expensive to repair

but roof prism models are easier or more comfortable for some people to hold

and they can be made to look more stylish.


Some binoculars have fixed focus.

Fine for youngsters with 20/20 vision and no difference between their left and right eyes.

No good if you are short or long-sighted as the acceptable focus becomes shorter so no infinity

or longer so nothing less than 40 feet is clearish.

Also no good if your eyes are different, as these models don't have an adjustable eyepiece.

Most binoculars have a focus wheel or two, some are bigger than others,

some have a fast action rocker system, some need small movements to alter the focus a lot

and some need a lot of movement.

As a general rule you want to be able to locate and focus on a subject such as a bird,

before it flies away so the focus system should be smooth and responsive,

not tight and jerky but not too quick nor too slow.

Most binoculars are made this way.

Don't be tempted to buy a binocular with individual focusing eyepieces unless you are used to that type of focus or try it first.

With a bit of practice, they are fine. They are also more rugged and easier to waterproof so often found on Military binoculars.


With optical instruments as with many products, you get what you pay for - well, to a certain extent.

The most expensive models offer a superior image to mid priced models

but a £600 binocular is not three times as good as a £200 model.

The difference between £200 and £400 may be noticeable

but you may see only a marginal improvement when comparing a £400 model and an £800 binocular.

Top quality optics are now being made in Portugal and Czechoslovakia as well as Japan;

Germany and Austri,. but do not disregard Chinese models as they can be really good.Top quality Chinese models are now available.

Recent advances in lens design using computers; wide spread use of multi coatings on lens and prism surfaces;

cheaper supplies of top quality BaK-4 glass and factories set up in cheaper labour markets

mean that today's £60 - £100 binoculars are remarkably good.

Double or triple that price and you will see improvements in colour definition;

edge definition; brightness of image and quality of manufacture.

Double that price and the improvements are marginal

but you probably get a nice name badge and a smart carry case.


Traditionally, camera retailers have also sold binoculars and telescopes.

Whilst the sales people are usually camera enthusiasts they often know little about binoculars and telescopes.

Fortunately some dealers recognised this failing and have become optical centres and they do know their trade.

At Action Optics we have always said if you get your binocular home or buy it mail order

and you don't find it as good as expected, then bring or send it back and try something else.

Your binocular has to be a treat to use; it should give that "wow" effect when you look through it

and find the image bright and clear in front of your eyes.

Don't put up with something that is not quite right because you will soon find it relegated

to the bottom of the wardrobe and we don't want that to happen.

If you don't use it, it won't get dirty and need to be cleaned

or it won't go out of alignment and need to be reset.

Cleaning and resetting binoculars and telescopes is how we mostly make our living.