• Binoculars for fishing, hunting and tourism. The right choice of binoculars for fishing, hunting and tourism

Binoculars are useful, and with its help one can make many interesting observations, in addition, binoculars are an excellent business gift. That is why the purchase must be taken seriously and take into account for what purposes you will use it.

The initial purpose of binoculars is clear to everyone - to consider distant objects. But at the same time, the field of application of binoculars can be very diverse. For professional purposes, binoculars are used by the military of almost all branches of the armed forces and employees of various law enforcement organizations, sailors, fishermen and hunters, search and rescue services, and so on.

A huge number of sports and recreational activities also require the use of binoculars, and often, binoculars can significantly reduce the danger associated with sports and outdoor activities.

In everyday life, binoculars are also useful. Do you like to go to the theatre? How many times did you have to regret that you don’t have normal, albeit pocket-sized, binoculars with you, through which the facial expressions of the actors are really visible, even from the last row of the amphitheater?

Of course, binoculars are an essential travel companion.

And we should not forget about the innate human curiosity: the desire to know the world, or ... to look into the windows of a neighbor. Here, without good binoculars not enough!

The choice of binoculars is not a simple matter, as it seems at first glance. Apart from various areas application, technical parameters, it is good to have an idea about what the quality of binoculars is like as an optical instrument, and what it consists of.
Components of binoculars, its characteristics.

Any binoculars in its composition contains a lens, a turning system and an eyepiece with an eyecup.

The main technical characteristics include the magnification and diameter of the objective lens.

Multiplicity (increase). Magnification refers to the apparent increase in the size of an object when viewed through binoculars. At a magnification of 10, the visible image is magnified 10 times. Some amateur binoculars have variable magnification, such as 8-20x. Thus, the image magnification can be adjusted from 8 to 20 times.

Objective lens diameter. This is a very important parameter of binoculars. It's about about the direct diameter in mm. the outer lens of the binoculars. It is indicated along with the magnification on any binoculars by the second number (7 * 50). Lenses with a larger diameter have a greater luminosity, that is, they let in more light, providing a brighter and more detailed image, and also have a wider angle of view. But the dimensions of the binoculars directly depend on the diameter of the objective lens - the larger the diameter, the greater the weight and dimensions of the binoculars.

These two parameters (multiplicity and lens diameter), as the most significant, are always marked in the name of the binoculars (for example: 8 * 40 binoculars, the magnification is 8 times with a lens diameter of 40 mm.).

Some binoculars have letters in addition to numbers in the marking. Usually they indicate a series or type of binoculars, and refer only to models of a particular manufacturer. They can also indicate the presence of a grid in the lens, water resistance, backlight, but each manufacturer has its own marking.

Depending on the chosen type of binoculars, you can study the proposed the lineup manufacturing firms. Each company produces binoculars of several series, and, accordingly, designed for different applications.

In this section you will find practical information to help you choose binoculars from the variety available on the Russian market. We did not set ourselves the goal of copying Wikipedia and giving general information of an encyclopedic nature, on the contrary, they tried to systematize our experience and those scattered data that can be found on the net.

The main characteristics of binoculars:

Typically, the name of the binoculars contains 2 or 3 numbers indicating the diameter of the lens and the magnification.
For example, Nikon Aculon 10x50 means binoculars with a magnification of 10x and a diameter of 50 mm.
Or Nikon Aculon 8-18x42 - means a variable magnification from 8x to 18x and a lens diameter of 42 mm.

Common mistakes when choosing binoculars

• The higher the multiplier, the better.
  This is far from being the case and depends on how and under what conditions the binoculars will be used, as well as on its aperture (lens diameter).
  If you want to make panoramic observations in the field or from a window, then you should not take binoculars with a magnification of more than 12x. Otherwise, the binoculars will give a small field of view, and they will most likely have to be mounted on a tripod.
  For binoculars with an aperture of less than 40, we recommend choosing a magnification of no more than 10x. Otherwise, the image may appear dark to you.
• Chinese binoculars are all poor quality
  Once upon a time this may have been true, but now such well-known manufacturers as Nikon and Zeiss are moving their production to China. And even lesser-known manufacturers have a line of extra-class binoculars made in China.
• The more expensive the binoculars, the better they are
  To simplify too much, it is. The expensive Zeiss is much better than the cheap Veber. But if we compare models different manufacturers, but of the same class (by type of optical glass, enlightenment, moisture protection), you can see that prices can differ significantly. Often it's all about marketing, or brand awareness. For example, Levenhuk (a relatively expensive brand) gives a lifetime warranty on its binoculars, but this does not mean that these binoculars are better than other Chinese counterparts.

FAQ

• I want to buy binoculars. What do you recommend?
  Depends on the budget of the purchase and the purpose of use. Of course, budget models are less preferred in terms of quality and functionality, but you can find suitable binoculars in every price segment. There are no universal binoculars for all occasions, and you will need to decide on your goals before buying.
• What manufacturer would you recommend?
  We recommend Nikon - these binoculars combine and high quality quite comparable to the price. However, in our assortment, not only this brand is worthy of attention, but also other manufacturers represented by us.
Are zoom binoculars perfect?
The idea to buy a device with a variable magnification (zoom binoculars), of course, is obvious. But we must remember that due to the design, the device is not hermetic (it can fog up or “catch” water), and in terms of quality, such an object will show a picture of worse quality than binoculars with a fixed magnification.
• What does the name binoculars mean? For the convenience of the buyer, the binocular manufacturer, the name of the line (budget, hunting, theatrical, etc.) and the magnification of the binoculars and its aperture (lens diameter) are included in the name.
  The magnification and aperture indicators are what determine the image in binoculars, its distinguishability and quality. The first digit in the binocular model is the magnification, the value of the magnification of the desired object. The second number is aperture.
  The higher the magnification, the larger the object, but the field of view decreases accordingly, and the image becomes darker. The larger the aperture, the more light will enter the telescope, the image will be brighter, but a larger aperture will increase the size of the binoculars.
  There are binoculars with variable magnification, it is usually indicated in the name by numbers through a hyphen.
• Why do binoculars have different shapes?
  It depends on the type of prisms used. Some (porro prisms) are machined from a single piece of optical glass, and the contours of the binoculars follow the complex shape of the prism, so some binoculars have a “step” between the lens and the eyepiece. Others use a roof prism, which is more compact.
  When it comes to image quality, different types prisms, then porro prisms are considered the best, although in modern roof prisms there is practically no loss of quality due to special processing.
• What is the best binocular magnification?
  The magnification of binoculars is always associated with expediency and range of applications.
  It is possible to create theater binoculars with exclusively high magnification- up to 20 times, but this will automatically give a small field of view and the ability to consider costumes of performers that are insignificant from the point of view of the plot.
  Usually, manufacturers themselves calculate the parameters necessary for various needs, among which you can already choose the desired range of multiplicity. But not only the multiplicity should be paid attention to - the aperture is very important, on which the illumination of the image depends.
• How to choose binoculars?
  Decide on the budget and purpose of use, the manufacturer continue to consider acceptable magnification (preferably in comparison) and illumination, paying attention to the necessary parameters - moisture protection (for use in bad weather), gas filling (lenses will not fog up), tightness (moisture or dust will not get into ), dimensions (they are affected by the type of prism).
• Nikon Action EX 10x50 CF and Nikon Aculon A211 10x50. What is the difference?
  The magnification and aperture of these binoculars are identical, and the dimensions differ very slightly. It can be seen that one model is twice as expensive as the other.
  In more expensive binoculars, there is also a gas filling of the pipes - this prevents the lenses from fogging.
  Also, in more expensive binoculars, the field of view is somewhat larger, and rubber as the material of the eyecups is more convenient if you look into the device for a long time.
• Which binoculars "give" a brighter picture?
  If you are guided primarily by the ability of the device to collect light, you need to pay attention to the diameter of the lens (aperture) and the coating of optical parts.
  The larger the aperture, the more light the binoculars will collect. But if you choose between coating options, preferably FMC - full multilayer coating of all optical elements.
• Why do you need a binocular bracket?
  Large binoculars are difficult to use without a tripod bracket: hands get tired, the image may begin to “shake”. The bracket will take the load and transfer it to the tripod.
  Mainly such support is needed for large astronomical models, marine binoculars.
• What binocular accessories can I buy?
  The main parts that you may need are usually already included in the kit. This is a strap for carrying the device on the chest, a case for safe transportation, a bracket (if necessary). There is no tripod included with the binoculars.

Main criteria when choosing binoculars

Lens diameter (aperture) — the most important characteristic optical instrument. Affects the aperture ratio, resolution, viewing angle, dimensions of the binoculars.
Field of view at a distance of 1000 m is the distance from the extreme right to the extreme left point of the region visible through binoculars.
Multiplicity (increase) How many times does the binoculars magnify the visible image? The higher the magnification, the larger the object, but the smaller the field of view and the aperture ratio of the binoculars (the picture is darker at high magnification). A more versatile option is variable power binoculars, but this versatility comes at the expense of image quality.
Prism system- serves to obtain a direct image when viewed through binoculars. Without prisms, the observer would see a mirror image. Prisms are Porro or Roof and affect appearance and dimensions of the binoculars. The design of Porro prisms is more bulky, but since the prism consists of a single piece of optical glass, it does not incur additional light loss. Roof prisms are more compact, but they are glued together from two optical glass elements and create additional light loss. To correct this effect, in advanced models of binoculars, a special phase-correcting layer is applied between the elements.
Type of optical glass prisms: BK7 (boron silicate crown) is an inexpensive glass used in basic models binoculars. BaK4 (barium crown) is a glass with a high refractive index, which results in less light scattering at the edges of the field of view.

What are binoculars for?

Binoculars for hunting
Binoculars with aperture from 35 to 50 mm and magnification from 7x to 16x. Preferably in a sealed and nitrogen-filled case, this will provide protection from adverse weather conditions.

Universal Zoom binoculars (for observations in the city and in nature)
Binoculars with variable magnification. The aperture and range of magnifications can be completely different, depending on the dimensions of the binoculars. Variable magnification makes it possible to use binoculars both for panoramic observations and for studying small details of a distant object. But this versatility also has a downside. The image quality in such binoculars is usually worse compared to the analogue of constant magnification.

Compact binoculars (for tourism and hiking)
Binoculars with aperture from 20 to 30 mm and magnification from 7x to 12x. Their main advantages are light weight and small dimensions. On the other hand, the small aperture makes these binoculars quite dark and limits their field of view.

theater binoculars
Theatrical binoculars are made according to optical scheme Galileo (no inverting prisms). Such a scheme gives compactness, but at the same time, a sharp deterioration in the picture at a multiplicity of more than 4x.

Astronomical binoculars
Large and heavy binoculars with apertures from 60 mm and magnification from 20x. Used to observe celestial objects. Due to its weight and dimensions, tripod mounting is required.

marine binoculars
These are waterproof binoculars that should provide maximum image brightness even in low light conditions. Usually the best option in this case, they are 7x50 binoculars. There are also so-called float binoculars. Often marine binoculars are equipped with a built-in compass.

Binoculars are not only handy tool for ground observation, which can be useful during a camping trip, expedition, hunting or travel. Modern binoculars can also be used, for example, for astronomical purposes, because they have a large field of view and powerful magnification. In addition, binoculars provide a direct image, unlike telescopes, where the image is inverted or mirror reflection. The shipowner may also need binoculars to survey the vast expanse of water.

In a word, the field of application of binoculars can be very different, which is why these devices are so different from each other - from very tiny models that fit in your pocket to heavy and bulky binoculars with a powerful optical system. The choice of binoculars seems very challenging task, because you will have to evaluate individual technical characteristics in combination with the weight of the device and, of course, the cost.

binocular design

By internal device allocate binoculars with a prism and lens turning system. The latter, however, is practically not used in modern models due to the fact that it requires a longer telescope. Of course, you need to focus on the prism system, and binoculars currently use two main types of prisms - these are Porro prisms (Porro Prisms) and Roof prisms (Roof Prisms).

Porro prism is a classic option, when the eyepieces are located not on a straight line, but in steps. Such prisms give a sharper and more contrasting image, as well as increase the perspective, so binoculars with such a prism system are well suited, for example, for astronomical observations. In turn, binoculars with a roof-prism are characterized by the fact that the lens is on the same line with the eyepiece. They are more compact and convenient, but more expensive.

The design of modern binoculars can be quite complex. It may include a multi-lens system that can bring the image closer to the ideal. Typically, however, binoculars only have six to ten lenses, the surface of which reflects a small fraction of the light that passes through them.

Depending on the number of lenses and, accordingly, the number of optical surfaces, 45 to 60 percent of the light entering the lens can reach the human eye. To reduce reflection from the optics, a special anti-reflection coating is applied to the surface of each lens, for example, in the form of magnesium fluoride. Such a coating is necessary in order to reduce light loss and reduce the likelihood of optical distortion.

The best option is when the optics is coated with a multilayer antireflection coating, consisting of several elements of different chemical composition. The quality of the enlightenment of an optical device is usually indicated in the description of the model from the manufacturer. There are standard terms here:

- "Coated" - a single-layer anti-reflection coating applied mainly to the outer surfaces of the lenses;
- "Fullycoated" - a single-layer coating that is applied to all optical surfaces;
- “Multicoated” - a multi-layer coating that is used only on some optical surfaces, while on others a single layer is used;
- "Fullymulticoated" - multilayer coating applied to all optical surfaces.

Main technical characteristics of binoculars

When choosing binoculars, you need to remember the main technical specifications this optical instrument:

— Magnification (multiplicity) of binoculars

And the first most important indicator here is the magnification of binoculars, that is, the ratio of the size of an object enlarged by binoculars to its size, visible to the human eye without using an optical device. For example, binoculars with a magnification of 10x increase the size of an object by 10 times. Today, there are binoculars on sale with magnification (multiplicity) from 3x to 25x. It is not worth chasing the maximum magnification value, it is better to choose the magnification of the binoculars that will suit your tasks.

In addition, at high magnification it is much more difficult to keep the object in the field of view of the binoculars, the vibration increases significantly, as a result of which it is necessary to mount the device on a tripod. Therefore, when buying binoculars with high magnification, it is recommended to check whether they have a threaded hole for mounting on a tripod. A good average binocular is considered to be a device with a magnification of 8 - 10x. Inexpensive binoculars for a tourist or an athlete are models with a magnification of 4 - 7x.

- Lens diameter

The next indicator is the diameter of the lens (entrance pupil) of the binoculars. The larger the diameter of the lens, the more light it is able to collect, which means that dimmer objects become visible and accessible to the observer. Thus, the brightness of the image in binoculars directly depends on the diameter of the entrance pupil. The diameter of the front lens of the objective is indicated in the marking in millimeters after the "x" sign. For example, 7x50, that is, binoculars with a sevenfold magnification and an entrance pupil diameter of 50 mm.

Man has invented many devices that help him or simplify his life. One of these inventions was binoculars, which allows you to view an object of interest at a remote distance. There are models of different designs that are used in certain areas. It is necessary to carry out the purchase of binoculars, based on specific parameters.

How to choose binoculars according to the main characteristics

When it comes to which binoculars are better, you need to pay attention to their optics. It has two most important characteristics - diameter and magnification. The manufacturers themselves indicate their importance by indicating these values ​​in the product name. For example, the Nikon Aculon W10 10x21 has a 10x zoom and a 21mm lens. All binoculars can conditionally be divided as follows:

1. With a fixed multiplicity, it cannot be changed. There are binoculars of small (2-4), medium (5-8), large (10-22) magnification.
2. With the zoom function (ZOOM), which provides the ability to change the approximation parameter in a specific specified range. For example, Veber ZOOM 7-15x35 adjusts the magnification from 7 to 15.

The diameter of the lens or the entrance pupil directly affects the luminosity of the device, the image quality, which helps to determine which of the binoculars is better. This part is also responsible for the viewing angle: the larger the lens, the larger the visible area through the device. It should be borne in mind that the diameter of the optics directly affects the dimensions and weight. Models with lenses up to 50mm are considered suitable for handheld use, values ​​above require the use of a tripod.

Opera glasses

When choosing this type of binoculars main characteristic should be the size. Ideally, if the device will fit in your jacket pocket or in a woman's handbag. Low magnification models are well suited because theater environments do not require a closer approximation. This will be enough to examine in detail the costumes of the actors, their faces. Such models are often sold in the theaters themselves and are called pocket binoculars.

Binoculars for hunting

There are several criteria that will help you understand how to choose binoculars for hunting. The difficulty lies in the fact that many people use different options when choosing a device. Yukon Point 8x56 is considered popular among hunters, but it weighs just over a kilogram, which complicates the observation process. Another hunting option is Fijifilm Fujinon 10x50, which does not even reach 840g, but the image quality is considered slightly worse. Unanimously, all lovers of fishing and hunting recognize that the device should:

• have good optics, a magnification of at least 8 and a diameter of 50-56 mm;
• weigh no more than 1 kg (this is the maximum weight that will not interfere with observation), but less is better;
• the case must withstand falls and other “tests” that are not critical for further operation.

Nautical

It is already clear how to choose binoculars with big increase, but in the case of boat trips, this criterion is not at all the main one. The device must have a moisture-resistant case so that water does not damage its components and does not spoil the image quality. Among professional users, Veber BPS 7x50 has proven itself well, which is able to survive even immersion in water, has a built-in illuminated compass.

Field or army

It is believed that the most powerful binoculars are military, but in fact this place is occupied by astronomical models. Army devices should not be so much rangefinders as they should have a set of specific functions. Their presence or absence determines which binoculars are good and which are not. List of options:

• built-in compass;
• laser rangefinder;
• electronic image stabilization;
• possibility of night reconnaissance.

Not always all these parameters are combined in one binocular, but they are also used to solve narrow specialized tasks. The main requirements of this type of device include:

• high luminosity;
• impact-resistant case, moisture protection, nitrogen filling;
• weight not higher than 1 kg;
• wide field of view - a value of 120x1000 m is considered acceptable;
• high-quality optics;
• separate focusing eyepieces;
• additional functions: rangefinder reticle, altitude scale, buoyancy, etc.

The best binoculars made in Russia and from foreign suppliers

Among fans of binoculars, models that were developed back in the USSR are highly valued. Then a lot of attention was paid to quality, standards. The main emphasis was placed on the production of military models with a high level of picture, high magnification. Now their design is very outdated, they are not as comfortable as foreign analogues. Factories continue to produce new versions of devices that are now of interest to lovers of tourism, to watch the stars. The price of such binoculars is usually lower, so people take them often.

This brand belongs to the SMOS plant and has a long history. Models of the device differ in magnification and lens diameter. Users note the good aperture ratio of optics. One of the main advantages of the model is its low cost. The disadvantages include weight, which increases proportionally with increasing lens size. If you choose the right model, then its characteristics will be in the rating no lower than those of imported counterparts.

Nikon Aculon A211 Zoom 10-22x50

Nikon, known for its high-quality optics, has released this model to replace the Action VII line. It uses Porro prisms, which are designed for all lovers of hunting, sports and tourism. The high magnification range (22x) is suitable for super long range surveillance. A function that helps you change the magnification of the binoculars will allow you to adapt to any conditions.

Olympus 8-16x25 Zoom PC I

This model has a ZOOM function, which provides the ability to zoom in and out of objects in the visual field. The minimum value of the multiplicity is 8, and the maximum is 16. The device helps to see everything in detail even when wearing glasses, but the diopter adjustment is small. Lenses provide a bright and high-quality picture. It is recommended to use binoculars for tourist purposes.

Veber Opera BHC 3x25R lorgnette

If you are wondering which binoculars are best for theatrical performances, then this model is for everyone. It is necessary to choose such device options, based on considerations of comfort and ease of use. This model perfectly combines an attractive, sophisticated appearance and compact dimensions, and the last argument should be low price. It has binoculars with 3x magnification, which is quite enough for theatrical performances.

Where to buy and how much binoculars cost

These products are sold in specialized stores. Theatrical models, as a rule, are offered directly on the spot, but tourist and military models must be bought strictly in specialized stores. Many online hypermarkets offer binoculars in their hiking gear section. As a rule, the price on the Internet is always somewhat lower. Estimated cost:

1. Theatrical - from 1000 to 3200 r;
2. Tourist - from 2000 to 40000 r;
3. Marine - from 8000 to 93000 r;
4. Astronomical - from 7000 to 63500 rubles.

Video: the right choice of binoculars

Beginners mistakenly believe that binoculars are a tool for ground-based observations, and their use for astronomical purposes is meaningless. This is wrong. Binoculars are not only an excellent tool for exploring the sights of the night sky, but also an extremely useful, and, in some cases, simply indispensable observer tool, which is recommended to have in the arsenal of every astronomy enthusiast.

The main features of binoculars

Let's look at both. The ability to conduct observations using both eyes, which is not only convenient, but also allows you to get a three-dimensional image thanks to the stereo effect.

Seeing more. Large field of view makes binoculars perfect tool for observing star fields, asterisms and bright comets. Also, binoculars are often used for a general overview of the constellations.

direct image. Binoculars give a direct image, while telescopes - inverted or mirror.

Main characteristics of binoculars

There are two main characteristics of binoculars - magnification and aperture. As a matter of fact, they are indicated in the name of any binoculars. Let's say 12x40, where 12 is the magnification and 40 is the lens diameter in millimeters.

binocular magnification

In optical instruments, magnification is usually denoted as X (read "fold") and indicates how many times the linear image of an object is magnified. So, binoculars with a magnification of 12X increase the size of the object by 12 times (makes it 12 times closer to the observer). As a rule, binoculars with a magnification from 7 to 25X are commercially available. It is worth noting that as the magnification increases, it becomes more difficult to keep the object in view, so it is recommended to install the binoculars on a tripod.

Binoculars mounted on a tripod using an L-adapter

Aperture

The aperture, or objective diameter, of binoculars is usually specified in millimeters. The larger the aperture, the more light the lens is able to collect, the dimmer objects become available to the observer. According to the aperture, binoculars can be conditionally divided into several categories:

• 
  1) standard binoculars - with lens diameter from 30 to 50mm. These binoculars are ideal for terrestrial observations. They are easy enough to hold in your hands, they are cheap and can be used perfectly for general viewing of the sky and the Moon.
• 
  2) Astronomical binoculars - With a lens diameter of 50 - 80mm, they have a large field of view and are an excellent choice for the astronomy enthusiast. Unfortunately, these binoculars are of little use for terrestrial observations due to their size and weight. For effective observations, such binoculars must be mounted on a tripod.
• 
  3) Large astronomical binoculars - with a lens diameter of 90 mm or more. These binoculars are quite rare, very expensive and, in fact, are telescopes, since many models have interchangeable eyepieces, which allows you to change their magnification.

Field of view of binoculars

Another important parameter is the field of view, the part of space visible through binoculars (it is also called true angle of view(Real angle of view)). In astronomy, the field of view of binoculars is usually denoted in degrees, which indicates how much of the sky will be accessible to the observer. Often, manufacturers indicate the so-called "linear field of view", which makes sense only for ground-based observations and is expressed in the maximum available linear image of objects (in meters) that can be seen from a distance of 1 km. The linear field of view in meters is easily converted to degrees, for this it should be divided by 17.4.

should be distinguished true angle of view And apparent angle of view(Apparent field of view). The apparent angle of the field of view is the product of the magnification of the binoculars and its true angle of view, expressed in degrees.

In general, for astronomical observations, a large field of view is a significant plus. But, unfortunately, ceteris paribus, with an increase in the field of view, the image deteriorates at the edges (various aberrations appear), so a compromise must be found between the size of the field of view and image quality. You can often find the following recommendation: with a magnification of 6x-7x binoculars, the optimal field of view is 6.5 -8.5 degrees, for 10x - within 5-7 °, and 12x binoculars should be chosen with a field of view of 4.5-6 °

exit pupil

The exit pupil of binoculars can be calculated as the ratio of the lens diameter to the magnification, i.e. 15x70 binoculars have an exit pupil of 70/15 = 4.7 mm. This is an important parameter, because according to the classical theory, if the diameter of the exit pupil of an optical device is larger than the diameter of the pupil of the human eye, then part of the light does not enter the eye. Thus, this is tantamount to reducing the aperture of binoculars (see the book "Amateur Astronomer's Telescope", by Seekoruk). It is believed that after adaptation to the dark, the diameter of the pupil of the human eye is 6 mm, and in urban conditions 4.5 - 5 mm. Take this into account when buying binoculars.

Eye relief

Removal of the exit pupil is the distance from the outer lens of the eyepiece to the point on the optical axis where the pupil of the eye should be placed in order to see a clear and sharp image. As a rule, the eye relief of binoculars is in the range of 10 - 20 mm. Small eye relief (10-15 mm) is most suitable for observers who do not wear glasses, so if you wear glasses, you should look for binoculars with a large eye relief, from 17 mm or more. In any case, before buying, you should check whether the eye relief is sufficient for specific model just for your eyes.

binocular prisms

There are two main types of prisms used in modern binoculars - Porro Prisms And Roof Prisms. Other things being equal, porro prism binoculars should be chosen for astronomical observations, as they provide a brighter, sharper, and more contrasting image.

It should be noted that there are two types of Porro prisms: BaK-4 and BK-7. Thanks to design features, BaK-4 let through almost all the light, which allows you to get the highest quality picture. In order to determine which Porro prisms are installed in the device, one should place the eyepieces of the binoculars at some distance from the eyes (usually at the distance of the exit pupil) and look at the image behind the eyepieces. If the image is round, then the binoculars use BaK-4 prisms, and if the image is diamond-shaped with brightness differences, then BK-7.

Schematic arrangement of binoculars with Porro prisms (left) and Roof prisms (right)

AR coating

Usually binoculars consist of 6-10 lenses, each surface of which reflects a small part of the light (up to 4%) passing through them. Thus, from 100% of the light entering the lens, from 45% to 60% reaches the observer's eyes (depending on the number of optical surfaces in the binoculars). To reduce reflection from lenses, a special anti-reflective coating is applied to each of the optical surfaces, such as magnesium fluoride (MgF or MgF 2). For binoculars consisting of 10 lenses, such a coating transmits an average of 73% of the light (reflecting 27%).

Much top scores gives the use of an antireflection coating, consisting of several layers of different chemical composition (multilayer enlightenment), which makes it possible to reduce reflection to a minimum. Unfortunately, manufacturers of binoculars (as well as any other optical device), wishing to reduce production costs, do not provide antireflection coatings for all optical surfaces, and also reduce the number of layers in the antireflection coating. Below is the standard terminology that describes the quality of the coating of optical instruments.