Choosing binoculars is a very serious and very difficult task. Do not think that the most important thing when choosing binoculars is its “magnification”. Binoculars have a fairly wide range of technical characteristics that must be considered when buying it. Therefore, before you go to the store to buy binoculars, you must first familiarize yourself a little with the basic terms and definitions, the structure and types of binoculars. And also to answer the question Why do you need binoculars?»
So what are binoculars?
Binoculars - an optical device consisting of two parallel telescopes connected together to observe distant objects with both eyes. Due to this, unlike the spotting scope, the observer sees a stereoscopic image.
binocular device
The main design elements of binoculars include:
* eyepiece lenses
* ocular cone
* prisms
* anti-kick cone
* objective lenses
* light
* upper hinge cover
* central focus wheel
* lower hinge cap (and tripod socket)
* rubber eye cup
* diopter ring
* diopter adjustment indicator
* bridge
* top case cover
* fastening of the neck belt
* bottom case cover
* objective barrel
* lens caps
Binoculars classifications
According to their dimensions, binoculars are classified into compact (with fixed and variable magnification) and classic (with fixed and variable magnification). Compact binoculars, as the name suggests, are much smaller in weight and dimensions than classic ones. They are generally recommended for use by hunters and hikers. But the classic ones can be suitable for a variety of purposes: hunting, fishing, birdwatching, wild animals, sports competitions. Binoculars are divided into two types according to the focusing method: with central focusing and with separate focusing.
Binoculars with central focusing are distinguished by the presence of a central screw, which ensures focusing for both eyes; at the same time, one of the eyepieces has its own focusing mechanism, which provides a diopter difference.
Binoculars with separate focusing are distinguished by the presence of their own focusing mechanism on each of the eyepieces. The following classification - by technical purpose - is the most important. Here there are several parameters at once, which determine whether the binoculars belong to one or another group: magnification, diameter of the entrance lens, diameter of the exit pupil, aperture ratio, field of view, etc. Based on different technical characteristics, they distinguish:
theater binoculars, designed to observe objects that are at a short distance from the observer (for example, in theaters, at concerts and stadiums). Such binoculars are distinguished, as a rule, by a small magnification (x2.5-5), a wide field of view, large aperture, as well as rather small dimensions and weight (due to the exit pupil diameter of 7-10 mm).
Compact binoculars also differ in small size and weight, but at the same time they have a large multiplicity. The diameter of the entrance lens of such binoculars is small, therefore, the diameter of the exit pupil, as well as the aperture ratio, is correspondingly small. Such binoculars are usually used for short-term observations in sunny weather.
Field binoculars are the most common, as they have good luminosity (the diameter of the entrance lens is 30-50 mm, and the diameter of the exit pupil is 4-7 mm), as well as a large magnifying power (from x7 to x20). Such binoculars are often used by signalmen, surveyors, topographers and power engineers.
Military binoculars are lightweight and portable, but at the same time durable and water resistant. The short length of such binoculars guarantees a wide field of view, which allows you to cover a fairly large area. Plus, such binoculars must have sufficient magnification.
Astronomical binoculars have a magnification starting from 6-7x and are usually used with a tripod (to avoid image shaking when zoomed in). Typically, astronomical binoculars are divided into three subspecies: 8x40 (wide angle of view, light enough), 7x50 (wide field of view, good aperture ratio, but not enough magnification, for example, to resolve double stars, bad when observing at dusk and in urban backlight), 10×50 (heavy, narrow field of view, but the maximum magnification, which helps to see the details). There are also specialized binoculars with high magnification (from 12x50 to 30x90), which are used only with a tripod.
marine binoculars are highly resistant to adverse weather conditions (have a unique waterproof coating). Plus, for the production of such binoculars, multi-layer smc-coated lenses are used, which reduces light loss. These binoculars, among other things, have a built-in 360-degree compass and a goniometric rangefinder scale. And of course, these binoculars have a very powerful magnifying power.
Night vision binoculars usually small and light, have a wide field of view and the best image quality in natural night-light conditions (due to a powerful IR illuminator of various ranges).
Main technical characteristics of binoculars
In order not to make a mistake with choice of binoculars, it is necessary to have at least a brief idea of its technical characteristics. We will not list them all, but consider the most important of them. This:
* prism wrapping system
* binocular magnification
* entrance pupil, or the diameter of the front lens of the objective
* exit pupil diameter
* light transmission of binoculars
* aperture
* field of view width
* focus system
1. Prisms turning system
Prism binoculars use two principles of prism inverting systems - porro (porro) and roof (roof). The inverting system of Porro prisms is a classic, binoculars with it have an easily recognizable shape: the distance between the lenses is greater than the distance between the eyepieces. In binoculars with roof prisms, the eyepiece and objective of each spotting scope are on the same axis. The use of roof prisms allows you to make binoculars compact. But the plasticity inherent in binoculars with the Porro wrapping system is lost in this case.
Thus, according to the principle of construction, binoculars are divided into 2 main types, depending on the type of prism of the inverting system (an optical system that turns the image turned upside down into the normal state obtained by the objective lenses):
* Roof prism binoculars ( compact binoculars) - lenses and eyepieces are located on common optical axes, which makes the binoculars more compact.
* binoculars with a Porro prism The optical axes of the binoculars' objectives are wider apart than the optical axes of the eyepieces, and because of this, the device is more bulky. But the quality of the image observed through such binoculars is higher.
2. The magnification of binoculars
The magnification factor of the binoculars determines how “closer” the observed object will be to you: for example, the opposite bank of the river, located 100 m from you, when viewed through 10x binoculars, will look like it is only 10 m away.
The higher the magnification of the binoculars, the more it "brings" very distant objects. However, as the magnification of binoculars increases, the comfort of observation decreases: the image begins to “jump” at your slightest movement. This means that binoculars with a high magnification factor (over 10) can be comfortably used, giving it the most stable position (installed on a tripod, rested against a tree trunk or car roof, etc.).
Thus, the choice of binoculars according to the criterion of magnification must be reasonable, otherwise the main advantage may turn into the main disadvantage ( True, there are binoculars with image stabilization, but this is a subject for a separate discussion.).
Magnification (fold)- the ratio of the angular dimensions of an object observed through binoculars to the dimensions of the same object, visible to the naked eye. Simply put, the multiplicity shows how many times the image seen through binoculars will appear larger than when viewed without binoculars. Binoculars can have constant (magnification) or variable magnification (zoom) magnification.
In the binoculars marking, the magnification is indicated in the first number before the “x” sign. Binoculars with low magnification are considered 2-4x, with medium magnification - 6-8x. High magnification binoculars are 10x, 12x 16x and even 20x binoculars. Such binoculars have large dimensions and weight, and are also expensive, therefore, when choosing binoculars, the magnification should be approached from the standpoint of reasonable sufficiency. In other words, the practical task that a person sets himself in a field and brings an optical device to his eyes is to recognize a distant object. And do not admire it at all or see it as large as possible. Therefore, the usual magnification (magnification) of binoculars intended for field observations is 6-8 times.
Sometimes a higher magnification is needed. But it must be taken into account that 8-10x magnification is a practical limit, after which observation from the hand becomes almost impossible due to jitter, the value of which is proportionally amplified by the optics in addition to a reduced field of view. Binoculars with strong magnification (15-20x) show their positive aspects when viewed from a tripod. To do this, special adapters are available that allow you to mount the binoculars on a tripod. In addition, the weight and dimensions of powerful binoculars are very significant, and they are not suitable for long-term wear.
There are also binoculars variable multiplicity (zoom). In them, the degree of magnification can smoothly change, as in zoomed lenses of photo and video cameras. The device of such binoculars, of course, is more complicated than usual. Binoculars, bringing the observed objects closer, do not deprive vision of its stereoscopic properties. This is the advantage of binoculars over spyglasses and monoculars. Stereoscopic vision makes it possible to distinguish the perspective arrangement of observed objects, their mutual distance, to see objects in volume.
The magnification characteristics of binoculars always appear in the model name and, as a rule, are indicated directly on the body of the device, for example, Delta Optical Sport 10x25 or Delta Optical Sport 8-24x25 ZOOM. The key here are the designations 10x25 and 8-24x25. Before the symbol "x" indicates the magnification of the binoculars. If there is one number, it is binoculars with a constant magnification factor, for example, 10, and if there are two numbers, binoculars with a variable magnification factor, in our example - from 8 to 24. By the way, if the model name contains the word ZOOM, we are talking about a device with a variable magnification factor . After the “x” symbol, the diameter of the lenses of the binoculars in millimeters is indicated.
3. Entrance pupil, or diameter of the front lens of the objective
The entrance pupil, or the diameter of the front lens of a lens, determines the amount of light that is involved in the formation of an image. The larger the diameter, the brighter the image in the binoculars. In binoculars, the size of the entrance pupil is indicated in millimeters after the “x” sign. Thus, the designation 8x36 indicates that these are eight-fold binoculars, in which the diameter of the front lens is 36 millimeters.
The diameter of the objective lenses determines the light transmission capability of the binoculars, that is, how bright the image you are observing will be. This parameter becomes especially important when observing at dusk, when the observed scene cannot be seen with the naked eye due to the fact that it is very far away, and nothing can be seen through binoculars due to the fact that it is very dark! The larger the diameter of the front lens of the objective, the more light falling on its surface it will collect, the brighter the image that we see through the eyepiece will be. Thus, of the two binoculars 8x20 and 8x40, 8x40 is more suitable for twilight observation. But 8x20 is much more compact.
4. Exit pupil diameter
Binoculars are optical instruments built according to the laws of geometric optics, and their characteristics such as the diameter of the front lens of the objective and the magnification are rigidly related to each other. Thus, another characteristic arises - the diameter of the exit pupil: the quotient of dividing the diameter of the front lens of the objective by the magnification factor.
For binoculars 8×20 binoculars will have an exit pupil diameter of 2.5 mm, and for 8×40 binoculars it will be 5 mm. This characteristic of binoculars is closely related to the possibilities of our vision, namely, the ability of our pupil to contract and expand depending on the lighting conditions. The pupil of a young, healthy person is able to expand up to 7 mm. With age, this ability is lost, and our pupil dilates to about 4 mm.
Based on the foregoing, if the diameter of the exit pupil of the binoculars is 2.5 mm, then during daytime observation, when our pupil is narrowed, this value is quite enough, but at dusk, when our pupil is dilated, it is desirable that the diameter of the exit pupil corresponds to the diameter of ours. If it is less, we will lose in the brightness of the observed image, if it is more, the optics will work in vain, since we are still not able to perceive an excess of light flux that does not fit into our pupil.
In this way, exit pupil is the diameter of the light beam entering from the binoculars into the observer's pupil. Numerically equal to the ratio of the magnification to the diameter of the entrance pupil. It is the size of the exit pupil that characterizes the binocular aperture, since with the same objective diameter, binoculars with a higher magnification will have a lower aperture than binoculars with a lower magnification. The optimal diameter of the exit pupil is 6-7 mm. Binoculars with a pupil of 3-4mm can produce a fairly bright image in sunlight, but at dusk they will be difficult to use.
Exit pupil diameter- an important characteristic of binoculars. The diameter of the exit pupil should not be confused with the diameter of the eyepiece itself. The exit pupil is that white spot that is reflected on a sheet of paper when we bring it to the eyepiece of binoculars aimed at the light, within the working segment. The working segment is the distance from the eyepiece at which the eye sees a clear image. The working segment is relatively large in optical sights, where it is necessary to take into account the force of recoil and the movement of the weapon back. Binoculars are designed for the direct approach of the eyes to the eyepieces and the length of the working segment is small and averages 10-15 mm, sometimes reaching 18-20 mm. In the latter case, the removal of the exit pupil allows the use of binoculars with glasses (in military binoculars - also through gas mask glasses). In order to determine the diameter of the exit pupil not by direct measurement of the light spot, but by calculation, it is enough to have the diameter of the lens, which is always indicated on the device itself by the number after the X sign - 8 X 40 - divided by the magnification. In this case, it is 5 mm.
5. Light transmission of binoculars
The ability of binoculars to transmit light is inevitably affected by the loss of light when it passes through the lenses and, especially, when passing through the glass-air barrier, since in this case additional light scattering occurs. It is possible to improve the characteristics of binoculars in terms of light transmission by increasing the optical quality of the lens glass, by reducing the number of barriers. glass-air» and through the use of special coatings on the surface of the lenses, called anti-reflective coatings.
In good binoculars, in addition to using high-quality lenses, optical components (objective, eyepiece) are assembled into monoblocks, in which the lenses are glued together with special adhesives to eliminate their contact with air. If the surface of the lens does come into contact with air, it is coated with a multi-layer coating (reflection), the optical properties of which minimize unwanted light scattering. Light transmission (Transmittance) - the ratio of the amount of light that comes out of the optical system to the amount of input light.
If the lenses of an optical instrument do not have an anti-reflection coating, this value can be less than 50 percent, since each air-tangent surface of the lens reflects approximately 5 percent of the light. A high-quality optical device, as a rule, contains 10–12 lenses. An antireflection coating allows you to increase the transmittance. The best optical instruments today have a transmittance of 97 percent.
Binoculars, which are specially adapted for twilight observation, have a lens coating that reflects the rays of that part of the spectrum that our eye does not perceive at dusk (or perceives poorly), but transmits rays that are well perceived by us. It is known that our eye at dusk best perceives the yellow-green part of the spectrum. The lens coating of good binoculars transmits rays from this range and reflects rays from the red and blue regions of the spectrum, so the lenses of such binoculars have a characteristic red-blue or purple reflection.
6. Aperture
Depending on the angle of view and the magnification of the optical device is its luminosity (relative brightness). Aperture determines the brightness of the image obtained on the retina when viewed through an optical device (in our case, through binoculars). Aperture is determined by the ratio of the brightness of the image of an object on the retina when viewed through an optical device to the brightness of the image of the same object on the retina when viewed with the naked eye.
The luminosity of the device is directly proportional to the diameter of its exit pupil. However, it is rather difficult to determine the magnitude of the aperture ratio from the above ratio. Therefore, in practice, the luminosity is denoted by an abstract number - the square of the diameter of the exit pupil. For 6x30 binoculars, the exit pupil will be 5 mm, and aperture, respectively, 25.
As is known, when light rays pass through an optical system, absorption and reflection losses occur, and the brightness of the image decreases. Therefore, when observing through an optical instrument, we see objects less illuminated than they really are. The more complex the optical device, the greater these losses.
To avoid additional losses in illumination Images, it is necessary that during operation the diameter of the exit pupil of the binoculars should not be less than the diameter of the pupil of the eye. The size of the pupil of the human eye varies depending on the illumination. Practice shows that the diameter of a person's pupil is from 2.5-3 mm in bright light, up to 7-8 mm at dusk and darkness.
Aperture, magnification and field of view of binoculars (any optical system in general) are closely related. You cannot change one of these settings without changing the others. Ceteris paribus, an increase in magnification will entail a decrease in the field of view. Increasing the exit pupil with this lens will increase aperture but decrease magnification.
7. Width of field of view
Also in the technical specifications there is such a parameter: the width of the field of view (angle of view), expressed in angular or linear values. For example, the width of the field of view of some 16x40 binoculars is 3° or 105 m by 1000 m. This means that the space observed through this binoculars expands as it moves away from the observer, and at a distance of 1000 m the width of the area visible through the binoculars will be 105 m In other words: if you construct an equilateral triangle whose vertex angle is 3° ( there is an observer), and whose height is 1000 m, then the width of the base of such a triangle will be 105 m.
With the help of geometry, it is possible to convert the angular width of the field of view into a linear one. In general, it is enough to keep in mind that the wider the field of view of your binoculars, the more valuable information you can get and the less time it will take to search for an object that you “spotted” with the naked eye. It should also be remembered that the higher the magnification of the binoculars, the narrower the field of view.
The field of view of binoculars is understood as the angle formed by two imaginary lines drawn from the center of the lens of an optical device to the extreme points of space, the boundaries of which are visible when viewed through the device. However, this is the real field of view. Distinguish between true and ocular field of view.
Unlike the true ocular field of view (apparent field of view) is the angle formed by lines connecting the pupil of the eye with the extreme points of the image built by the optical system in the device. Accordingly, the ocular field of view is larger than the true one in proportion to the magnification of the instrument. Sometimes both of these characteristics are indicated. If the field of view (true) of 6x binoculars is 100, then the ocular field of view is 600. Often the field of view is indicated not by a degree angle, but by the width of the viewed segment at a certain distance. These values are easily converted from one to another.
8. Focus system
And finally, it is necessary to mention the various focusing systems, because the eyesight of all people is different, and it is required to achieve the sharpest possible “picture”. Most compact (roof prism) binoculars are equipped with a central focusing system: one of the eyepieces has a diopter adjustment ring, with which you adapt the binoculars to the features of one of your eyes while closing the other, and then achieve sharp vision with the remaining eye using the drum central focus. As a result, the “picture” then observed by both eyes will be sharp if the difference in “optical characteristics” between your eyes is not too great.
V binoculars with a Porro prism, separate focusing of the eyepieces is more often used, which allows you to fine-tune each “half” of the binoculars, taking into account the characteristics of your vision. Good binoculars also differ from mediocre ones in their great depth of field. For example, with good binoculars, an object at a distance of 20 m from you and an object at a distance of 300 m will be seen equally sharply. In addition, binoculars are characterized by such a parameter as the minimum focusing distance. So, through 16x binoculars, you can sharply observe objects located no closer than, say, 15 m. The smaller the value of the minimum focusing distance, the more comfortable the observation.
So the focus binocular eyepieces may be central or separate. In the first case, the handwheel common to the two eyepieces is located at the swivel of the tubes, in the second case, the adjustment is made separately by direct rotation of the diopter ring of each eyepiece. Separate focusing is more typical for military binoculars, because. the design becomes simpler and stronger.
Other Important Features of Binoculars
Now let's talk about the performance characteristics of binoculars. The binoculars must have sufficient mechanical strength, that is, to withstand shocks, bumps, falls, which are very likely in the harsh conditions of extreme travel. The body of the binoculars, moreover, should be comfortable so that you can hold them securely, and should not slip out of your hands even in heavy rain. Special article - moisture resistance body and the tendency of lenses to fog from the inside. Separately, you should consider those binoculars, the body of which is 100% waterproof (waterproof).
And so that the lenses do not fog up from the inside during temperature changes and atmospheric humidity, the body of the binoculars is filled with nitrogen under vacuum conditions. Filling the body of the binoculars with nitrogen (Nitrogen-filled) indicates its high class, which, however, inevitably affects the price.
Designations on binoculars
Here it is immediately worth dividing all the binoculars into Russian and non-Russian, since the designations on them will differ significantly from each other. On Soviet and Russian binoculars, the designations are indicated in Cyrillic. Below are the most common abbreviations:
"B" - binoculars,
"P" - prism binoculars,
"G" - Galileo's binoculars,
"K" - compact binoculars,
"P" - field binoculars,
"T" - theater binoculars,
"C" - sports binoculars,
"B" - high-luminosity,
"B" - high magnification,
"W" - wide-angle,
"C" - central focus,
"F" - internal focusing,
"O" - extended exit pupil.
For example, the abbreviation BPC on binoculars would mean "prism binoculars with central focusing." Russian binoculars the abbreviation consists of three or four letters: the first letter is B (binoculars), the second is the type of binoculars (Galileo - G, or prism - P), the third is compact (K) or not, the fourth is the purpose (field, theater, sports) or feature (high aperture, high magnification, wide angle, etc.). At the end of the abbreviation, there may also be a number - the model number of the binoculars (for example, BPC5).
Now consider the abbreviations that are indicated on the binoculars of foreign manufacturers.
l.e. - extended exit pupil;
WA - wide-angle binoculars;
Spot - large depth of field, no focus;
UCFmini - ultra-compact;
UCF V - compact, Porro prisms;
DCF - compact "with a roof";
CF - standard size, Porro prisms;
PCF III - standard binoculars, Porro prisms;
WP - waterproof, up to a depth of 1 m;
PIF - waterproof, 5m deep, filled with dry nitrogen, multilayer coated, separate focusing;
EXPS - binoculars of a high category;
HR - quality;
IF - with distance scale;
BD - with a laser rangefinder;
IS - optical image stabilization;
AF - autofocus;
N - night vision binoculars.
Also, whole words can be written on binoculars, for example ZOOM - variable magnification, as well as, of course, the name of the company (for example, Nikon).
Binoculars for fishing, hunting and tourism
Binoculars for tourism- This is the largest selection of all kinds of models. Often, the buyer, choosing binoculars for tourism, is lost in a variety of options and chooses the binoculars he needs for a long time. This is because almost all binoculars are suitable for tourist purposes. But, as elsewhere, there are several basic parameters on which, we would advise you to focus your attention as much as possible:
overall dimensions binoculars can be any, as well as the security of the case. Here it is not necessary to take sealed and waterproof binoculars, it will be enough to take just a rubberized model. Adequate magnification (you should not take binoculars with a magnification of 30-40-50x on a trip. 10x will be quite enough). Large lens diameter (try to focus on the standard 10x50, where 50 is the diameter of the lens. Such binoculars will let in a lot of light and have a wide field of view).
Hunting. In any hunt, dynamism is important. Therefore, binoculars that are suitable for tourism are completely unsuitable for hunting due to their size. In hunting, dimensions play a huge role, and the smaller they are, the better. Therefore, it is better to choose binoculars with a magnification of 4 to 7 and a lens diameter of 25-40 mm. Here, as in tourism, it is important to have durable rubberized binoculars, but without excesses.
Fishing. In case you are going to go fishing or sailing on a yacht, then, perhaps, the only main property that you should worry about in binoculars is moisture protection. Because, splashes will certainly fall on the binoculars, which can get inside and ruin the optical design. Sealed binoculars with moisture protection prevent this. The magnification and diameter of the lens is up to you.
What should you pay special attention to when buying binoculars!
So, you got acquainted with the structure of binoculars, learned about the main technical characteristics of binoculars, decided for what purposes you need binoculars. Now feel free to go to the store! Here are a few tips that you may find useful when buying binoculars.
* buy binoculars only from a reputable manufacturer. Production technology plays a decisive role in the production of binoculars. If a company has been producing telescopes, microscopes and cameras for more than a year, then you can safely buy their binoculars. The choice is so great that you can buy expensive binoculars for professional work and inexpensive binoculars for home use.
* magnification should not be a decisive factor when buying binoculars. Try an experiment. Take two binoculars from the same manufacturer with different magnifications, for example, 7x50 and 12x50 and look at a sheet of text attached 15 meters from you. You can check that 7x50 binoculars make text easier to read, as it lets in more light and has a larger angle of view.
* All people are individual. When working with binoculars feeling of comfort is very important. When buying, be sure to look through binoculars in daylight. If someone from your acquaintances praises a certain brand of binoculars, this does not mean at all that this binoculars will suit you.
* pay attention to the body of the product: it should not be deformed, the painting should be even, and there should be no scratches on the lenses. Remember, the main thing in binoculars is the objective lenses, so you should pay attention to them first of all. If you notice even small scratches or dirt on the lenses, immediately refuse to buy such binoculars. By the way, in order to check the lenses for the presence of any debris, you need to look into it at a light solid background.
* test the binoculars on distant objects. Pay attention to the quality of the image: it should not double, the contours should be clear, colored “auras” are not allowed around objects ( evidence of chromatic aberrations). Also take note of your own feelings. Remember, if you feel any excessive tension in your eyes, then this copy is not worth buying (most likely, the parallelism of the axes is violated in it).
Binoculars This optical device can be an excellent memorable gift for a man on his anniversary. Also, binoculars...
Binoculars have always been a popular type of optical instrument used for a variety of purposes. It is also an integral part...
The choice of binoculars Binoculars, being a popular optical device, are supplied by many manufacturers for mass production. Quantity...
Binoculars are a compact observation device consisting of two identical optical channels, each of which contains a lens, a turning system and an eyepiece, structurally designed in the form of two hingedly connected tubes - monoculars. Binoculars are used to observe distant objects with both eyes. The most common types of binoculars at present are prism binoculars, in which the image is flipped using a prism system. The two main prismatic systems are Porro prisms and Roof prisms.
The presence of two optical channels preserves a person’s three-dimensional spatial vision or a stereoscopic effect, that is, it provides the ability to feel not only the height, width, but also the depth of the space perceived by vision, or, in other words, retains the ability to evaluate the size, volume, spatial arrangement of objects based on direct visual sensation , space relief.
Binoculars on a hike, on a trip or on a country walk can be very useful. With it, you can see what attracted attention from afar, without approaching. And thereby save yourself, on occasion, from an extra path or wandering, and even from an extra meeting. This is the main task assigned to field binoculars and determining its properties.
In other words, the practical task set by a person who is in the field and brings an optical device to his eyes is to recognize a distant object. And do not admire it at all or see it as large as possible. Therefore, the usual increase(magnification) binoculars intended for field observations - 6-8 times. Sometimes a higher magnification is needed. But at the same time, it must be taken into account that 8-10x magnification is a practical limit, after which hand-held observation becomes almost impossible due to jitter, the value of which is proportionally enhanced by the optics, in addition to a reduced field of view. Binoculars with high magnification (15-20x) show their positive aspects when viewed from a tripod. To do this, special adapters are available that allow you to mount the binoculars on a tripod. In addition, the weight and dimensions of powerful binoculars are very significant, and they are not suitable for long-term wear. There are also binoculars. variable multiplicity(zoom), also called pancratic. In them, the degree of magnification can smoothly change, as in zoomed lenses of photo and video cameras. The device of such binoculars, of course, is more complicated than usual.
The next important characteristic is lens diameter(entrance pupil) binoculars (mm). These two parameters, as a rule, set the characteristics of binoculars in the most general form, for example: 6x35 means a magnification of 6x, the lens - 35 mm. Since the binocular aperture parameter is related to the diameter of the lens, when choosing the diameter, it is necessary to decide in what light conditions you will mainly use the binoculars. In low light, the lens diameter should be larger. On the other hand, a lower magnification factor makes it possible to observe at lower illumination with the same lens size: 7x50 binoculars have better illumination than 10x50 binoculars.
Universal for use in field conditions, hunting, etc. are binoculars with parameters 6x30, 7x35, 8x40. If you want to observe very distant objects in the daytime, binoculars with 8-10x magnification and a lens diameter of 30-40 should be preferred. If the observation will take place at reduced illumination, at dusk or at dawn, then you need to choose a larger diameter, and, possibly, give up the increase, stopping at the ratios 6x42, 7x42, 7x50.
Exit pupil size binoculars is defined as the ratio of its diameter to the magnification, say, for 6x30 binoculars it is 30:6 = 5. The optimal ratio is considered to be close to the diameter of the pupil of the human eye (7 mm).
Another important physical characteristic of binoculars is field(or angle) vision. It is usually set in degrees and determines the width of coverage of the given visual device. Note that this value is related by an inverse proportion to magnification: the more powerful the binoculars, the smaller its field of view. Binoculars with a large field - wide-field or wide-angle.
Depth of field- the range of distances to the target, in which it is not necessary to change the adjusted focus. It is not indicated in the parameters of the binoculars as an indicator, but it is important to consider that it decreases with increasing magnification of the binoculars.
The universal method of focusing is central, it allows you to quickly bring the binoculars into focus, observing, for example, a moving object. However, binoculars separate focusing are more reliable. In addition, they provide better conditions for people who have significantly different levels of vision in the eyes. Some of these binoculars have divisions for focusing in accordance with the level of vision: so that a person, knowing the diopter of his eyes, can immediately adjust the eyepieces. Center focusing binoculars sometimes have an eyepiece adjustment mechanism to adjust for different eye diopters.
Exit pupil removal- the distance to the eyepiece at which the binoculars can be focused. With a distance of 18-20 mm, you can observe with glasses or, for example, in a gas mask. For ordinary binoculars, this distance is 10-12 mm. Binoculars with eye relief can also be used without glasses: the eyepieces are "extended" with soft plastic rings.
So, you have decided to choose binoculars. Where to begin? It all depends on your future plans. If you are going to take it with you on a hike, hunting, expedition, role-playing game or orienteering competition - you need field glasses, but sports binoculars may also be suitable.
Sports binoculars can be a good gift for a teenager. If you like extreme sports or go to a friend's or boss's birthday and want to show that you think he is a really cool man, night vision binoculars will come in handy for you. A gift to your beloved mother-in-law is theater binoculars. If you are a ship owner or are fond of astronomy, then you will probably need binoculars with powerful magnification.
What are the characteristics of these models?
The defining property of binoculars is magnification (multiplicity). This is the ratio of the size of an object as seen by binoculars to its size as seen by the naked eye. This characteristic of modern binoculars is in the range from 3x magnification (theatrical binoculars) to 22x (heavy powerful binoculars are usually used with a tripod).
By magnification, binoculars can be divided into groups:
low magnification (2-4 times)
medium magnification (5-8 times)
high magnification (10-22 times).
Let's add right away that chasing magnification at the expense of other characteristics of binoculars is about the same delusion as wanting the maximum number of megapixels from a digital camera: first you need to understand what magnification is required for your specific tasks.
Most binoculars in the mid-price range fall into the mid-range range. It is quite enough for a tourist, hunter or sportsman. Inexpensive sports binoculars have 4-5 times magnification. Binoculars with a magnification of 7-10 are considered good. It should be noted that 10x magnification is the maximum at which it is possible to use the binoculars while holding them in your hands. At higher magnifications, image vibration increases so much that a tripod or built-in image stabilizer is required. By the way, the weight of powerful binoculars is such that no one will probably want to hold them in their hands for a long time: 1.5-2 kg, or even more. When buying powerful binoculars, you should pay attention to whether it has a threaded hole for mounting on a tripod.
There are binoculars with adjustable magnification (with "zoom"), but they are more complex and, as a result, more expensive. In addition, these binoculars are capricious in handling. Note that fixed magnification binoculars are better than analogs with zoom in terms of their optical characteristics, since it is not possible to provide high image quality at all magnifications.
The next important characteristic is the diameter of the lens (entrance pupil) of the binoculars (mm). These two parameters, as a rule, set the characteristics of binoculars in the most general form, for example: 6 × 35 means a magnification of 6x, the lens is 35 mm. Since the binocular aperture parameter is related to the diameter of the lens, when choosing the diameter, it is necessary to decide in what light conditions you will mainly use the binoculars. In low light, the lens diameter should be larger. On the other hand, a smaller magnification allows observing at lower illumination with the same lens size: 7x50 binoculars have better illumination than 10x50 binoculars.
Universal for use in field conditions, hunting, etc. are binoculars with parameters 6×30, 7×35, 8×40. If you want to observe very distant objects in the daytime, binoculars with 8-10x magnification and a lens diameter of 30-40 should be preferred. If the observation will take place at reduced illumination, at dusk or at dawn, then you need to choose a larger diameter, and, possibly, give up the increase, stopping at the ratios 6 × 42, 7 × 42, 7 × 50.
The value of the exit pupil of binoculars is defined as the ratio of its diameter to the magnification, for example, for 6 × 30 binoculars it is 30:6 = 5. The optimal ratio is considered to be close to the diameter of the pupil of the human eye (7 mm).
Another important physical characteristic of binoculars is the field (or angle) of view. It is usually set in degrees and determines the width of coverage of the given visual device. Note that this value is related by an inverse proportion to magnification: the more powerful the binoculars, the smaller its field of view. Binoculars with a large field - wide-field or wide-angle.
Depth of field - the range of distances to the target, in which it is not necessary to change the adjusted focus. It is not indicated in the parameters of the binoculars as an indicator, but it is important to consider that it decreases with increasing magnification of the binoculars.
The three-dimensionality of the image (it is also called stereoscopicity or plasticity) is provided by the periscopicity of binoculars - a property in which the lenses (outlets) of the binoculars are separated wider than the eyepieces (inlets). Stereoscopicity is considered a plus, for example, in the field. In the theater, on the contrary, it interferes with the perception of what is happening on the stage, so the theater binoculars are designed so that the distance between its lenses is equal to the distance between the eyepieces.
Turning system device
According to the internal structure, binoculars are divided into binoculars with a prism and lens turning system, but the latter is practically not used in modern binoculars, since it requires a longer telescope. The most commonly used prism turning system, proposed by the French optician Porro.
In addition, modern binoculars often use inverting systems with special prisms that have a "roof", that is, two faces located at right angles to each other and similar to a gable roof.
Focusing
The universal way of focusing is the central one, it allows you to quickly bring the binoculars into focus, observing, for example, a moving object. However, binoculars with split focus are more reliable. In addition, they provide better conditions for people who have significantly different levels of vision in the eyes. Some of these binoculars have divisions for focusing in accordance with the level of vision: so that a person, knowing the diopter of his eyes, can immediately adjust the eyepieces. Center focusing binoculars sometimes have an eyepiece adjustment mechanism to adjust for different eye diopters.
There are also focus free and autofocus binoculars, which, as a rule, provide not very high image quality, but are convenient for situations in which a long adjustment is impossible, for example, for firefighters or rescuers, as well as for observing a rapidly moving object.
Exit pupil removal- the distance to the eyepiece at which the binoculars can be brought into focus. With a distance of 18-20 mm, you can observe with glasses or, for example, in a gas mask. For ordinary binoculars, this distance is 10-12 mm. Binoculars with eye relief can be used without glasses: the eyepieces are “extended” with soft plastic rings.
The night vision - night vision binoculars form a separate group of devices using infrared radiation. An additional important characteristic for them is the time of continuous operation of the power source. It is essential to have IR illumination for working in extremely dark conditions, as well as a protection system in case of accidental activation in bright light.
When choosing good binoculars for hiking, you will find that binoculars that look the same at first glance are very different in price. The familiar cliché “you get what you pay for” is especially true with binoculars. The prices for binoculars usually correspond to the quality of the optics.
None of the factors can determine that one model of binoculars is better than another. Which binoculars to buy is determined solely by your personal preferences and purpose of use. The best binoculars are the ones that suit your personal style.
Types of binoculars.
To choose the right binoculars, decide what is more important to you - image quality or the weight and dimensions of the binoculars. Binoculars come in a variety of sizes, determined by the size of lenses designed for a variety of purposes.
Standard size binoculars(general specifications: 8 x 42, 10 x 50):
- Capture more and perform better in low light conditions.
- Typically provides a stable image and a wide field of view.
- Popular for serious wildlife viewing and boating.
- Too big and heavy for .
Medium binoculars(general specifications: 7 x 35, 10 x 32):
- Optimum balance of size and light transmission.
- A good choice for both wildlife watching and sporting purposes.
- A bit heavy for hiking.
Compact binoculars(general specifications: 8 x 25, 10 x 25):
- The lightest compact option for backpacking trips.
- Very good for hiking.
- Not so comfortable for extended use.
Monocular(one field of view):
- The smallest and usually the easiest choice.
- A monocular is generally preferred for short term use.
Technical characteristics of binoculars.
binocular magnification.
Binoculars have two characteristics of magnifying power. The first is the magnifying power, and the second is the diameter of the front lens of the binoculars. How to determine the magnification of binoculars?
For example: 7 x 35 binoculars have a magnifying power of 7.
A magnification power of 7 means that the object will look 7 times closer than if you were looking at it with the naked eye. For example, if you look through 7x binoculars at a deer standing 183 meters away from you, it will appear as if it were standing 26 meters away (200 divided by 7). So what binoculars to choose? Probably with the largest possible magnification of the binoculars, so that there is a better view. Right? Not necessary. High magnification binoculars (greater than ten) amplify the movement of your hands, making it difficult to view calmly.
Objective lens diameter.
The second technical characteristic of binoculars, used to identify binoculars, refers to the diameter of the objective lens in millimeters (the farther from the eyes, the closer to the “object” of observation).
For example: 7 x 35 binoculars have an objective lens diameter of 35 millimeters.
The diameter of the objective lens largely determines how much light the binoculars can collect. If you have two binoculars with absolutely exact specifications, except for the lens diameter, then binoculars with a larger objective lens diameter will collect more light. The more light, the brighter the picture, especially in low light conditions.
Exit pupil.
The exit pupil is a numerical value of binoculars that indicates how bright objects will appear in low light conditions. A larger number means a brighter picture.
Point your binoculars at a light source. Hold it at a distance of about thirty centimeters in front of your face and look into each eyepiece. See the little bright dots? These circles of light are known as exit pupils, the channels that allow light to exit each barrel of binoculars and reach a person's eyes.
Exit pupil size is measured in millimeters and is calculated by dividing the objective lens diameter by the magnification factor.
For example, for 7 x 35 binoculars, divide 35 by 7 and get the size of the exit pupil equal to 5 millimeters.
The wider the exit pupil, the more light passes through it. The result is a brighter picture in low light conditions. If you intend to use the binoculars in low light conditions - at dawn, dusk, in the shade of dense trees or while observing the night sky - choose binoculars with a large exit pupil, preferably four millimeters or more.
When using binoculars in normal daylight, the size of the exit pupil is not so important. In bright light, the size of the human pupil narrows to about 2 millimeters. All binoculars have an exit pupil larger than two millimeters.
However, in dim light, our pupils can dilate up to 7 millimeters. For example, 7 x 50 binoculars offer an exit pupil of 7.1 millimeters, a good choice for viewing in low light conditions. The large exit pupil also helps to capture the full picture, especially if your hands are shaky.
relative brightness.
Relative brightness is determined by squaring the value of the exit pupil. The larger the relative brightness value, the brighter you see the object, which is useful in low light conditions.
For example, the value of the exit pupil is 4.3. Square this number (4.3 x 4.3) to get a relative brightness value of 18.5.
So the same value of the exit pupil gives the same level of relative brightness? No, high-end binocular manufacturers reply, arguing that a host of details—prism type, lens elements, component quality, and optical coating—all contribute to relative brightness.
Removing the exit pupil.
Eye relief is the distance between each eyepiece and your eyes while the entire field of view is visible. The large eye relief value increases your comfort by allowing you to keep the binoculars away from your face. This characteristic is especially useful if you are wearing . Most manufacturers recommend that spectacle wearers remove the rubber rings on their eyepieces before viewing. But there are exceptions to this general rule.
Tip: If you wear glasses, choose binoculars with an eye relief of 11mm or more.
Line of sight.
This binocular specification determines the width of the area (usually in feet) that you can see through the binoculars at a distance of 914 meters from you. The wide field of view is the best choice for finding and identifying objects such as birds. Usually, higher magnifying power is the result of a reduced field of view.
Conclusion.
Once you narrow down your choice of binoculars to a certain category, your choice of a particular model of binoculars will already depend only on your financial capabilities and individual factors, such as compatibility with glasses. Remember that the quality of binoculars primarily depends on their optics.
Basic parameters of binoculars
Magnification (multiplicity) and objective lens diameter
Usually these parameters are indicated on the body of the binoculars, for example "10x40".
- The first number (10) is the multiplicity, it tells us that with this binoculars we will be able to see an image of an object 10 times larger (in angular measure) than with the naked eye.
- The second number (40) shows the entrance aperture of the lens in millimeters, or, to put it simply, the diameter of its front lens. The larger the lens, the more light it collects and produces a brighter image.
Exit pupil diameter
Accordingly, for viewing from binoculars in low light conditions, binoculars with an exit pupil diameter of at least 4 mm are required, and at night, preferably 5 - 7 mm, depending on age.
The dusk factor
This is a relative value that depends on the magnification of the binoculars and the diameter of the objective lens. In this case, the quality of the optics is not taken into account.
The dusk factor is calculated by multiplying the magnification by the diameter of the front lens and taking the square root of the result.
When observing in low and twilight conditions, binoculars with a higher twilight factor coefficient are recommended.
Focus mechanism
Most prism binoculars have a central focus. In this case, the sharpness is first adjusted for the left eyepiece (left eye) by turning the central focusing drum (wheel): then, if necessary (if the observer has different visual acuity in the left and right eyes), the right eyepiece is adjusted. In the future, refocusing of the binoculars on closer or more distant objects is carried out only by the central drum. There are binoculars with individual or separate focusing of each eyepiece, i.e. the eyepieces are not linked by a mechanical system. In this case, each refocusing of the binoculars requires adjustment of both the left and right eyepieces. According to this scheme, binoculars with a rangefinder or goniometer scale, marine binoculars with a sealed housing, specialized astronomical binoculars are made. Some binoculars do not have a focusing mechanism as such: the optical system gives a conditionally clear image from a certain distance to infinity, similar to a photographic lens set to a hyperfocal distance (see DOF); adjustment to distant and near objects is possible only due to the natural ability of the eyes to accommodate. The advantages of fixed focus binoculars include simplified design and, consequently, reduction in cost, increased reliability due to the absence of moving parts and improved waterproofness of the case.
Focus range
Sometimes you have to look through binoculars at objects that are in close proximity, for example, a butterfly on a flower. For such observations, binoculars with a minimum focusing distance of no more than 0.5-1.5 meters are required.
Multilayer enlightenment
In the technical characteristics of binoculars, data on the quality of optical elements are rarely found, although the final image quality depends on this:
- non-coated lens reflects 4 - 5% of the light flux
- single-coated lens - about 1%
- multi-coated (SMC) lens - only 0.2% of the light.
Since the design of binoculars uses not one, but several lenses, in practice, light loss is even greater. For example, for binoculars consisting of 6 uncoated elements (12 surfaces), the light loss will be approximately 40%, while for the same design with lenses with SMC coating it is only 2.4% (that is, 17 times less). Optical coating also minimizes internal reflections, improving image clarity, color reproduction and contrast.
Accordingly, by the color of the outer lenses of the binoculars, it is already possible to draw certain conclusions - what quality of the lenses and with what type of coating they are made.
Aspherical elements
Extended ocular point
Many binoculars have an extended ocular point due to the large working length of the eyepiece. This means that during observation it is possible to hold the binoculars at some distance from the eyes and still see the full image. In this case, it is possible to look through the binoculars with glasses without degrading the image.
New properties
Image stabilizer is one of the new features of modern binoculars. These binoculars have two gyroscopes that operate from built-in batteries. They are enough for several hours of work.
Types of binoculars
- Sports binoculars
- Free focus binoculars
- Binoculars with rangefinder scale
- Binoculars with integrated compass and rangefinder
- Gyro-stabilized binoculars
- Binoculars for viewing platforms
Notes
see also
Links
 |
Wikimedia Foundation. 2010 .
Synonyms:- Explanatory Dictionary of Ushakov
- (French binocle, from Latin bini pair, two and oculus eyes), optical. a device for visual observation of distant objects with two eyes, as well as for measuring angles and distances. Consists of two spotting scopes connected so that their optical. axes ... ... Physical Encyclopedia
- (Binocle, binocular) an optical instrument consisting of two connected telescopes for viewing distant objects. Samoilov K.I. Marine Dictionary. M. L .: State Naval Publishing House of the NKVMF of the USSR, 1941 Binoculars ... ... Marine Dictionary
Binoculars- prismatic, with a wrapping system of prisms. BINOCLES (French binocle, from the Latin bini pair, two and oculus eyes), an optical device of two parallel telescopes for observing distant objects with both eyes. Binoculars… … Illustrated Encyclopedic Dictionary
- (French binocle from lat. bini pair, two and oculus eyes), an optical device for viewing distant objects with both eyes. Consists of 2 spotting scopes connected in parallel. Gives 222x magnification... Big Encyclopedic Dictionary
BINOCLES An optical instrument that is viewed with both eyes at the same time. Gives an enlarged view of a distant object or area. Consists of a pair of identical telescopes (one for each eye); it has a lens with a lens, ... ... Scientific and technical encyclopedic dictionary
Binoculars, me, husband. Hand-held optical device of two parallel-connected telescopes for viewing distant objects. Field b. Theatrical b. | adj. binoculars, oh, oh. Explanatory dictionary of Ozhegov. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Explanatory dictionary of Ozhegov
Husband, lat. double spotting scope, Mazuriks have two-eyed eyes. Dahl's Explanatory Dictionary. IN AND. Dal. 1863 1866 ... Dahl's Explanatory Dictionary
Exist., number of synonyms: 3 two-eyed (1) stereo binoculars (1) telebinoculars (1) ... Synonym dictionary
Two optical tubes connected together, known to everyone as binoculars, can be useful to a person in a variety of situations. Binoculars have always been a popular accessory, ranging from children's models and theatrical varieties to advanced technical devices for field or astronomical observations. Demand for binoculars is quite active, and manufacturers offer many options with a wide variety of characteristics. You need to focus on the company's reputation, experience and reviews, but Carl Zeiss, Nikon, Canon, Pentax and some others are considered industry leaders as standard.
Despite the general principle of operation, binoculars can differ significantly from each other depending on the parameters, dimensions, and taking into account some other features. That is why knowledge about the design of the apparatus and the characteristics that affect its properties are important. The better you understand the theory, the more likely it is that the money (sometimes very significant amounts) will not be wasted.
Binoculars are divided into two large groups:
- optical (they are also Galileo's tubes, or theatrical ones) - are intended more for entertainment and everyday observations;
- prismatic - have the best visual characteristics and are used for field observations.
The stereoscopic effect caused by the presence of two optical channels provides an opportunity to feel the real size of the object, relief, depth at a distance, but it is also important which prismatic systems are in the binoculars.
Prism binoculars are the most widely used type of binoculars today. The two main structural models - Porro and Roof - turn the picture upside down, increasing it for the observer. How are they different?
Classic Porro-type prisms have a lens with an eyepiece that is stepped, while providing plasticity, but the binoculars look more bulky. This shape (the distance between the lenses is greater than the interocular distance) provides the best image quality. Roof systems are more compact, cheap and light due to the arrangement of all elements on the same axis, but their user characteristics are somewhat worse.
Key features of binoculars
In addition to wrapping systems, many other factors affect the quality of binoculars. The main ones include, first of all, what determines the parameters of the device even at the household level - magnifying multiplicity. It shows how close an object will become when viewed through binoculars. It is necessary to remember the reasonableness of requests, because with an increase in the multiplicity, comfort decreases: the image will begin to be blurred when the observer moves, the depth of field decreases, and so on.
If you need powerful binoculars, then a tripod is also desirable with which the optical device will be securely fixed. The multiplicity is the ratio of the angular values that characterize the object. It is indicated on the label with an "x". Small binoculars - 2-5x, large - from 10x.
A practically comfortable magnification limit is 9-10x, in addition, constant and variable magnifications must be taken into account. Zoom binoculars that allow you to change magnification are more complex, but allow you to vary the settings depending on the needs of the user, which makes them more convenient for general use. Constant magnification parameters fix its value, providing a significant increase in image quality.
The first digit of the marking indicates the magnification, and the second ‒ the diameter of the front lenses on the lens. The parameters of the entrance pupil is another important characteristic of binoculars, which determines its aperture component (how bright the picture will be, how much light the lens will collect), overall dimensions, useful magnification, and so on.
With an increase in the diameter of the lens (i.e., aperture ratio), both visibility in low light and the angle of view increase. It defines the resolution limits, i.e. the ability of binoculars to detail an object. The smaller the angle value, the better the resolution of the instrument. It should be taken into account that the luminosity and magnification of binoculars are inversely related: so the image at dusk will be better (ceteris paribus) for a model with a small increase.
Exit pupil size on lenses are also important. This value is the result of dividing the size of the front lens by the magnification parameters. Thus, 8x20 binoculars will have an entrance diameter of 2.5 mm. It is related to the ability of the pupil to expand and contract as the amount of light entering it changes. The exit pupil determines the size of the light beam that enters the observer's eye. The optimal diameter (and, therefore, aperture) is from 6 to 7. Smaller numbers will give a good image on a bright sunny day, but will be useless in the dark. If observation is expected in difficult conditions, twilight, and so on, then it is better not to chase the increase, focusing on the aperture ratio.
Speaking of the exit pupil, you need to remember about its removal, that is, the distance from the lens to the eye itself. The larger this value, the more convenient it is to use binoculars for those who wear glasses, and too short a distance can be uncomfortable, for example, in cold weather, so a distance of 9-12 mm will be optimal.
The luminosity, which determines the brightness of the image that the eye receives, and the light transmission features of binoculars are closely related to its magnifying properties. The larger the output diameter, the greater the aperture characteristics, and a larger aperture will make the magnification smaller. Such a direct dependence forces you to carefully select the parameters of the binoculars in order to maintain a balance.
The next indicator is field of view dimensions. Width is expressed in degrees as well as linear units. It shows what part of the overall panorama a person will see through binoculars, i.e. how much information will be available to him. This indicator has an inverse relationship with magnifying power: highly approximating devices are usually narrow in the field. Wide-angle binoculars are characterized by a large coverage angle, but a smaller magnification.
Antireflection coatings on lenses, the light transmission coefficients are increased, i.e. This indicator determines how many percent of the light will pass through the lens, and how much will be reflected from it. This reduces optical distortion and makes the object "more visible". A similar effect is given, for example, by aspherical lenses that increase contrast.
Focusing system ensures image sharpness. It can be of central or separate type. The central, common on compact models, the focusing system is adjusted by a central knob, allowing you to quickly make the approaching object sharp and clearly visible.
