The determining property of optical binoculars is the increase (multiplicity). This is the ratio of the size of the object in an enlarged binocular to its size, apparently with the naked eye.

By increasing it can be divided into groups:
• small increase (2-4 times)
• average magnification (5-8 times)
• large magnification (10-22 times)

Most of the produced binoculars of the middle price group fall within the range of average magnification. This is quite enough for a tourist, a hunter or an athlete. Inexpensive sports binoculars have a 4-5 fold increase. Binoculars with an increase of 7-10 are considered good. 10-fold increase - the maximum at which it is possible to use binoculars, holding it in your hands. At higher magnification, the image vibration increases so much that you need a tripod or built-in image stabilizer.

There are binoculars with adjustable multiplicity (with "zoom"), but they are more complicated, and as a consequence, more expensive. In addition, such binoculars are capricious in circulation. We note that, due to its optical characteristics, binoculars with a fixed multiplicity are better than analogs with a zoom, since it is not possible to ensure high image quality at all magnifications.

An important characteristic of the binocular is the diameter of the lens (entrance pupil) of the binoculars (mm). With this parameter and multiplicity, as a rule, the binocular characteristics are set in the most general form, for example: 6x35 means the multiplicity 6x, the lens 35mm. Since the lens diameter of the binoculars is related to the diameter of the lens, choosing the diameter, it is necessary to decide the question of what kind of illumination you will mainly use binoculars. At low illumination, the diameter of the lens should be greater. On the other hand, a smaller magnification allows to observe at a lower illumination with the same lens size: for binoculars 7x50 the illumination is better than for 10x50.

Universal for use in hiking conditions, hunting, etc. binoculars with the parameters 6x30, 7x35, 8x40. If you want to observe very distant objects during the day, preference should be given to binoculars with a magnification of 8-10 and a lens diameter of 30-40. If, however, the observation occurs with reduced illumination, at dusk or at dawn, then you need to choose a larger diameter, and perhaps give up an increase, stopping at the ratio of 6x42, 7x42, 7x50.

The size of the exit pupil of the binocular is defined as the ratio of its diameter to the multiplicity, say, for binoculars 6x30 it is 30: 6 = 5. The optimal ratio is close to the diameter of the pupil of the human eye (7 mm).

An important characteristic of a binocular is the field or angle of view. It is usually set in degrees and determines the width of the coverage of this visual device. The magnitude of the field of view is related to the ratio of the inverse proportion to the increase: the more powerful the binoculars, the smaller its field of view. Binoculars with a large field - wide-angle or wide-angle.

Depth of field - the range of distances to the target, in which you do not need to change the adjusted focus. It is not indicated in the parameters of binoculars as an indicator, but it is important to take into account that it decreases with increasing binocular magnification.

The volume of the image (it is also called stereoscopic or plasticity) is provided by the periscopicity of the binoculars-a property in which the lenses (exit holes) of the binoculars are diluted wider than the eyepieces (the entrance apertures). Stereoscopy 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.

Removing the exit pupil is the distance to the eyepiece at which the binoculars can be sharpened. When removing at 18-20 mm, you can monitor with glasses or, for example, in a gas mask. In ordinary binoculars, this distance is 10-12 mm. Binoculars with removal of an exit pupil can be used and without glasses: eyepieces are "elongated" by soft plastic rings.

When choosing binoculars, it is worth checking the softness of the adjusters, the convenient arrangement of the buttons, in particular the stabilizer button, go out with binoculars for daylight, try to read the book a distance of ten meters

"RONBO.RU" Moscow
2007