FAQ's - Frequently Asked Questions Binoculars
1. What can I use my binoculars for?
2. What do the numbers mean that appear on most binoculars – for example, 10x42?
3. How can I keep my binoculars clean?
4. What are the best binocular brands?
5. How big should my binoculars' field of view be, and is this something which varies considerably?
6. What does phase coating mean?
7. What's the difference between porro prism binoculars and roof pentaprism binoculars?
8. Is it really worth spending a lot of money, or is it possible to find a pair of cheaper, good quality binoculars?
9. How can you test the quality of a pair of binoculars?
10. Isn't it true that the larger the magnification, the better the binoculars?
11. You sell zoom binoculars as well. Am I right in thinking that these are better than a pair of binoculars with just one specific magnification?
14. Are there binoculars that are designed for both day and night observations?
15. I'm looking for a pair of binoculars for birdwatching. What would you recommend?
16. Is it worth getting a pair of binoculars with image stabilisation?
17. I want to mount my binoculars on a tripod. What sort should I go for?
19. What binoculars would you recommend for glasses wearers?
20. Which eye cups are the best?
21. What should I look for in particular when it comes to buying binoculars?
22. What do all the initials in your binocular descriptions stand for?
1. What can I use my binoculars for?
Binoculars are the perfect piece of equipment for seeing far-off objects larger and in more detail. Some typical uses are for astronomy, birdwatching, nature and animal watching (for example, on safari), hunting and sailing. But really, their uses are limitless – you could use them when travelling, when out walking in the mountains, at sports events, concerts, theatres, operas and for all sorts of every day uses.
2. What do the numbers mean that appear on most binoculars – for example, 10x42?
You'll find these sorts of numbers on every pair of binoculars that we have on our site, and they're to do with magnification and lens diameter. The first number always stands for the binoculars' magnification, so in the above example, the magnification would be 10 times. The second number always stands for the lens aperture (always in millimetres), and so 10x42 binoculars have an aperture of 42mm.
3. How can I keep my binoculars clean?
Remember that binoculars are an everyday item which should be used and enjoyed, not locked away in a glass cabinet. So of course, at some point they'll become a little dirty. The casing can be easily wiped using a cloth, but you'll need to take a little more care when cleaning the lenses. There is a sensitive coating on the lenses that can be damaged if you're too rough when cleaning. The golden rule when it comes to cleaning is to do it as seldom as possible.
It's perfectly fine to gently go over the lenses with a soft cleaning brush if you're trying to remove a speck of dust, and you can do this as and when you need to. But if there's slightly heavier dirt on the lenses, then this isn't the case, and you should remember that a thorough cleaning should not be carried out on a regular basis. It's best to use a microfibre cloth or another kind of very soft cloth. Be careful that there are no large specks already on it, and then gently wipe the lenses in soft, circular movements. These gentle movements might not be enough to remove the dirt, and in that case you can buy a special cleaning fluid from us so that you can clean them properly. Remember that it's always best to put the caps back on the lenses after you've used your binoculars.
4. What are the best binocular brands?
The high-end, top quality brands are Leica and ZEISS. Very good quality brands include Steiner, Minox and Nikon. Brands of a good quality are Eschenbach, Bushnell and Bresser. Some other brands, however, have particular binoculars which are excellent and might be better for certain uses.
5. How big should my binoculars' field of view be, and is this something which varies considerably?
It's always good if binoculars have a large field of view. Between both eyes, a human's field of view is usually 180° - with binoculars, this is of course not realistic. However, it's best to look for the biggest field of view possible, and along with the magnification and the eyepieces, it's an important factor when choosing your binoculars. Generally, the smaller the magnification, the larger the field of view, but you can also get special wide-angled eyepieces which offer a larger field of view along with a higher magnification. You'll have to weigh up whether this is worth it or not though, as when many of the cheaper manufacturers offer binoculars with a bigger field of view, often you'll find that about a third of the image isn't so sharp around the edges. Good binoculars should always provide a high-quality, sharp image right up to the edge.
If you're looking at the field of view in figures, it's always given out of 1000m – for example, 56m/1000m. This means that in a thousand metres' distance, your field of view will be 56 metres. This is also sometimes given as an angular degree, and you can then work out how many metres this is yourself by using the equation below. 1° is equal to 17.5 metres of field of vision, so:
Field of vision in 1000m = degree (real number) x 17.5=
Degree (real number) = field of vision in 1000m / 17.5=
6. What does phase coating mean?
Some high quality field glasses are marked as being “phase coated”. This means that there is a special coating on the roof pentaprism, more often known as the P-coating. When a ray of light hits the roof pentaprism, it's reflected multiple times in the form of a “roof” angle. As it's reflected, the ray is divided into two. This process creates a shift in the phases of the light waves, and instead of them all being equal, they're staggered. This results in the resolution and the contrast being reduced, but the application of special layers can prevent this from happening.
7. What's the difference between porro prism binoculars and roof pentaprism binoculars?
The differences between porro prism binoculars and roof pentaprism binoculars are mainly to do with the different systems of prisms that are used to turn the imagethe right way round again. The two systems of prisms are, as the names suggest, porro prisms and roof pentaprisms. To put it simply, with the porro prism the path of the rays goes in a right angled shape, where as with the roof pentaprism the path of the rays travels in a nose angle shape, like the roof of a house. Roof pentaprism binoculars have generally become more popular than porro prism binoculars. The way the two of them look is also quite different. The lenses of porro prism binoculars are set somewhat further apart, where as roof pentaprism binoculars are more compact and slimline. The reason for this is that the prisms are built differently. But despite their relatively chunky form, the advantage of porro prism binoculars is that they provide a very vivid picture. Their focusser is on the outside, where as roof pentaprism binoculars have a screw focusser in the tube. This is often why people prefer the porro prism binoculars, because they are often more sturdy and better protected from coming into contact with water and damp. It's impossible to say which design is better, because with both types there are the good and the not so good pairs – however, it's a lot more expensive to produce a good pair of roof pentaprism binoculars, and therefore the budget-conscious should bear this in mind and seek advice before purchase.
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8. Is it really worth spending a lot of money, or is it possible to find a pair of cheaper, good quality binoculars?
Like with many things, the more money you spend, the better quality you'll get. If you don't want to spend too much, it is possible to get a fairly decent quality pair. But if you're not willing to make much of a compromise when it comes to colour aberration, contrast, sharpness, transmission and an accurate picture, more expensive binoculars are a must. With more expensive binoculars, more money is spent on ensuring good optical and mechanical performance so that the aberration is kept under control as much as possible. You want the mechanical focusser to be of high quality, as when this part doesn't work properly – for example, it's loose or sticky – observing won't be much fun. You also shouldn't be willing to make too much of a compromise when it comes to the eye cups, as they can really make observing more comfortable. There are different types with different functions - for example firm, twist up eyepieces.
9. How can you test the quality of a pair of binoculars?
It's not easy to determine the quality straight away, and if you're looking through them in nice weather in the countryside, you'll often not even spot the differences that can actually occur between the many different binoculars around. Other than the optics, you'll of course also be looking for the focussing mechanics and the optical tube.
First of all, you can hold the binoculars under white neon lamps and check the coating. You'll immediately see whether the lenses have reflex colouration or not (mostly green or violet). If the reflexes are white, it means the binoculars have no coating and this means that valuable light will be lost before it reaches your eyes. Check exactly the same thing when it comes to the eyepieces – some cheaper producers don't use any coating at all. Apart from the loss of light, uncoated binoculars can mean higher reflexes, which you certainly want to avoid.
Next, hold the binoculars at some distance from a bright light, and you should see two white slivers in the eyepieces. These are the exit pupils, and they should be round and not too angular. If they are too angular, this means the prisms are not able to reflect enough light. This is a huge design flaw which can severely compromise the image.
Next, have a look through them against the light. With lower quality binoculars, it's quite possible that on the horizon, reflexes will occur which can enormously reduce the contrast in the image. Inside the binoculars it should be black matt.
You should also look for good, clear quality of colour. To check this you should point the binoculars towards a sunlit wall at home, and this way you might also be able to tell if there are colour fringes. If these are too strong then the image will be compromised, so colour free lenses are always better. Various manufacturers offer binoculars with ED or fluoride lenses, and these binoculars have barely any colour aberration (the higher the magnification, the more important this is).
It's good to test binoculars under the night sky as well, as then you'll be able to notice the aberration more easily. Focus on a bright star, a bright planet or even the moon, trying to make the object in the centre of the picture really sharp. Then move the object round to the edge of the field of view. This way you'll be able to see if there's any aberration – for example, if the star looks blurred around the edges. You'll also be able to establish if the edges aren't sharp enough and if the field of view curves at all. The bigger the lenses are, the more you'll be able to notice the aberration.
10. Isn't it true that the larger the magnification, the better the binoculars?
It's a widespread belief that the larger the strength of the magnification, the better the binoculars – but this is not the case. In actual fact, you'll also need to take into account the materials used, the prisms, the coating and the mechanics. Therefore the magnification should be appropriate for what you intend to use them for.
For most observations, a 8 or 10 times magnification should be quite enough. Up to this kind of magnification, you should be able to hold the binoculars quite still in your hands. With a higher magnification (over 12 times) that won't really be possible any more. The picture will move about and become less sharp, and so you'll probably then want to set the binoculars up on a tripod. Binoculars generally come in magnifications of up to 20 times. If you prefer to have a higher magnification but you don't want to use a tripod, there is the possibility of buying binoculars with image stabilisation.
If you like an even higher magnification, a spotting scope would be the best. Spotting scopes usually offer magnifications of between 20 to 60 times and can be set up to use a zoom lens. Of course, if you're using a spotting scope, a tripod will be necessary. With most spotting scopes, a table tripod is also included.
- Recommended binoculars 10 times magnification
- Recommended binoculars with 12-times magnification
- Spotting scopes with table tripod
11. You sell zoom binoculars as well. Am I right in thinking that these are better than a pair of binoculars with just one specific magnification?
Zoom binoculars are very practical. They allow you to set the magnification to suit, so they're good if you plan on carrying out a different sorts of observations. However, you'll be making a compromise with this type of binocular. The additional lenses that make the zoom function work are of a lesser quality than the lenses on a pair of fixed magnification binoculars. If it's sunny and daylight, this isn't something you're likely to notice, but you will when you want to define contrasts or it's dawn or nighttime. Most zoom binoculars have a tunnel effect, which generally worsens as the magnification increases. This gives the effect of looking through a long black tunnel, and only zoom function field glasses won't have this flaw.
12. I'm looking for a pair of binoculars which are appropriate for water activities. What would you recommend?
For practising watersports, you should go for a robust pair of binoculars that have good quality lenses and a stable construction. They should have a complete rubber covering, as this means that they won't slip so easily in your hands. It's also good if they're water pressure-tight, lots of binoculars offer this up to a depth of 5 metres. They should be nitrogen filled, as this avoids them steaming up if moisture gets inside, and an additional Neoprene strap will ensure that they stay afloat if they fall into water.
13. I'm looking for some binoculars which I can use when I go walking in the mountains. What would you recommend?
For walking, we recommend you avoid anything too heavy as you'll probably already be carrying a lot. The highest you should be looking at are 10x42 universal binoculars. They weigh around 700 grams and so are easy to carry, and they're also good for observing at dawn. If you're looking for something even lighter, you might want to try something like a 10x25 pair. They're so compact, that they'll even fit in your pocket and they only weigh about 300 grams. The downside is that they can really only be used during the daytime when there's a lot of light (AP 2.5mm). Apart from the aperture and lenses, other important factors you should be looking at include the coating on the lenses, prisms and the materials used – here is where you'll be able to tell the differences in quality.
14. Are there binoculars that are designed for both day and night observations?
There are “universal” binoculars that can be used in all lights. Universal binoculars can be 10x42 or 8x42 – a 42mm lens aperture and an 8 or 10 times magnification. The important thing is how much light is allowed to enter the eye. With 8x42 binoculars, a light beam enters the eye with a diameter of 5.25mm. This means that even at dawn you'll get a bright image with sufficient light on the retina. These binoculars can also be used during the night, and in fact, this is arguably when they're at their best. Look for the highest quality lenses possible, as the type of glass is used, the coating they have and how they reflect are all important features.
15. I'm looking for a pair of binoculars for birdwatching. What would you recommend?
Accuracy of colour is a very important factor if you're birdwatching, as you'll be wanting to recognise the different colours of the birds' feathers. For this, you'll probably not be looking at the cheapest binoculars, instead you'll want ones with a good quality coating. If you're looking at roof pentaprisms, the prisms shouldn't have simple coating, but instead a variety of dialectric coatings. Apart from that, the prisms should have a P-coating. This ensures that no phase shifting of the light sources takes placein the prism. If you're after pocket binoculars and wear glasses, you should ensure that the eyepieces are suitable. If you take all these factors into consideration, you should get a pair of binoculars which offer a great brightness, contrast and colour accuracy.
16. Is it worth getting a pair of binoculars with image stabilisation?
It's always worth getting a pair of binoculars with image stabilisation if you're looking for a high magnification but you don't want to use a tripod. It's also good for people who don't have a steady hand. It uses electronic sensors to balance out movements so that even a pair of binoculars with 15 times magnification can be held steady. Optically, the image appears very sharp because any movement is cancelled out.
17. I want to mount my binoculars on a tripod. What sort should I go for?
Most binoculars offer the possibility of mounting them on a tripod. On the bridge there's usually a cap that you can unscrew hiding a ¼'' thread. You can then secure a pair of binoculars onto a tripod with a tripod adapter. When it comes to choosing the right tripod, you'll need to think about what's right for you. It of course doesn't make sense to mount heavy, 1000g binoculars on small, lightweight tripods. The binoculars would be too heavy for the tripod, the tripod would wobble and you wouldn't be able to observe properly.
Tripods are mostly made out of aluminium, wood or carbon. Aluminium is very light, so the materials and construction should be strong enough to ensure the whole thing doesn't wobble. Wooden tripods are mostly made out of ash, and these will barely wobble at all. For good stability, it's not only the materials that are important, but also the weight of the tripod itself. With some good tripods you'll be advised of a maximum load limit, and you should abide by this recommendation.
18. What does coating mean?
Coating is when thin layers of metal are deposited on optical lenses in a high vacuum. They minimise reflections on the lenses and this in turn maximises the amount of light that's allowed through. Often these layers are made of of magnesium fluoride. Layer thickness and refractive index are vital qualities which affect how much reflexes are reduced and how much interfering light is cancelled out.
Usually there'll be not one, but several layers (up to seven or even more), and this ensures good reflex reduction throughout the spectrum. You'll easily be able to recognise the coating by its colour, which is normally purple or green.Be sure that your chosen binoculars are labelled as “multicoated”.
19. What binoculars would you recommend for glasses wearers?
If you want to be able to look through your binoculars with your glasses on, then it's important that you have suitable binoculars. Some binoculars are not designed for glasses wearers and they'll offer only a very small and limited field of view.
To get the optimal view, it's important that the exit pupils are further out and at around 20mm away from the eyepieces. The eye cups must not cause you any nuisance, and they are actually adjustable on lots of binoculars. Some are made out of duroplastic plastics, others are are softer and detachable. Although the latter can be soft and comfortable on the eye, bear in mind that they can also become brittle over time.
20. Which eye cups are the best?
Eye cups are important to avoid the interference from outside light. There are soft, rubber eye cups or eye cups which are made of duroplastic plastics. The advantage of the harder, twist up eye cups is that they last for a long time and often have several different variable shutting functions.
Rubber eyepieces are softer and can be detached if desired. However, bear in mind that over a long period of time they can become brittle.
21. What should I look for in particular when it comes to buying binoculars?
Glasses wearers must absolutely make sure they buy a pair which have a large enough eye base. A distance of around 20mm is important so that the whole field of view can be seen without any shadowing towards the edges.
People with light ametropia should watch out for the position of the eyepiece. It's important to find out up to which dioptre is suited to the field of view and eyepiece, and also whether or not the eyepiece has a detent to counter any accidental movements.
You can check one important quality after purchase by pointing the binoculars towards a white area from about 30cm away. Through the binoculars you should be able to see a round, white area which doesn't get darker toward the edge. This means that the light is coming through the eyepiece and reaching your eye properly.
Certain things can only be noticed once you've been using the binoculars for some time. With most low quality binoculars, you'll notice that the prisms aren't aligned properly. This can give you a headache if you use them for a long period of time, and you might get double images.
Something very important in a pair of binoculars is the coating of the lenses and prisms. Normal optical lenses reflect some of the light which falls on them, and this leads to a loss of light and a weakening of contrasts. By coating the lenses (the deposit of a metal layer to prevent reflection), reflections will be greatly reduced and more light will be allowed through.
22. What do all the initials in your binocular descriptions stand for?
WP - waterproof. Special watertight rings are used, the pores are also made thoroughly waterproof and the vacuum behind the glass is filled with nitrogen. They are particularly well-designed for all activities which involve venturing out in changing weather conditions, for example, walking in the mountains or sailing.
B - this means that they are suitable for glasses wearers. These binoculars have a large eye base which allows glasses wearers to see everything in the field of view without any shadowing
G, GA oder RA - this stands for rubber armed These binoculars are well protected against knocks and scrapes, they are also water resistant.
CF - this sometimes stands for central focus, but also for close focus. In porro prism binoculars, eyepieces are connected over the bridge and can be adjusted by moving the focussing wheel (the central focusser) back and forth.
"Close focus" means that the binoculars have a very small nearest point of focus, usually between 2 and 4 metres, where as “normal” binoculars usually only provide a sharp image from around 5 metres onwards. If you like to observe smaller, closer objects, for example butterflies or birds, you should go for these.
W, WF, WW oder Wide - these all stand for wide angle – binoculars with a very large field of view.
MC - stands for multicoated. But this might not necessarily be noted, as all high quality binoculars will have several layers of coating anyway.
UC - ultra compact – small and lightweight binoculars (most will be made out of aluminium, or sometimes titanium).
HP - high eye point – these binoculars have a large exit pupil aperture.
D - stands for roof prism
IS - stands for image stabiliser. Binoculars with an image stabiliser are particularly popular with bird and nature watchers.