How to choose modern binoculars

First of all, you need to decide for what purpose you want to buy binoculars. There are universal options, but it is best to purchase a device for specific purposes. All existing binoculars can be divided into several types, consider the most common.

Types of modern binoculars

Levenhuk Broadway 325F is relatively inexpensive theater binoculars providing 3x magnification

Theatrical. As the name implies, these binoculars are used in theaters, as well as in various performances, concerts, etc. They are usually light and increase only 2-5 times. Theatrical binoculars have a lens with a diameter of no more than 30 cm (see below for diameter and magnification). The main indicator for this type is a wide field of view and high-quality work with minimal lighting.

Universal. The most common type of binoculars, characterized by relatively low cost and average performance. Such devices are usually quite large (due to the optical design used in them), but at the same time they can provide a magnification even higher than 20x, like these models. Universal binoculars are suitable for those who decide to take optics “just in case”. It is not suitable for hunting or, say, stargazing.

BRESSER Astro 20x80 - binoculars with 20x magnification both for terrestrial, but also astronomical observations

Marine. This type of instrument is highly demanding. This is a more specialized technique that must meet certain standards. Firstly, marine binoculars are equipped with maximum protection against dust, moisture, fog, mechanical damage, etc. All of them are moisture resistant (do not confuse moisture resistance and water resistance). They also have a rubberized body for a more secure fit in the hands and additional protection against damage. Marine binoculars are often equipped with a built-in compass and rangefinder. In other words, the device has everything for regular use in aggressive marine conditions. Their cost, of course, is appropriate.

Astronomical. This is perhaps the most powerful type of binoculars on the market. Their main distinguishing feature is a high magnification rate (there are models with a magnification of 40x and more) and, accordingly, a large lens diameter. It turns out a low-cost version of the telescope. Powerful astronomical binoculars are suitable for studying the moon or even nebulae. That's just it is extremely inconvenient to use them "by hand", so it is better to install on a special tripod. The lens diameter here can reach 150 mm.

Specifications of binoculars

The most important aspects when choosing binoculars are the diameter of the lens and the magnification of the device. Both parameters are indicated in the model name. For example, the designation 7x50 indicates that the binoculars give a 7x zoom and have a lens with a diameter of 50 mm.

Let's start with the lens. Its diameter is measured in millimeters and directly affects the size of the field of view and the brightness of the image. If it is very simplified, then the larger the area of \u200b\u200bthe lens, the more light passes through, therefore, the picture is better. From here comes the next important parameter - relative brightness. It can be conditionally divided into several categories:

From 1 to 10 - for use in bright light.

11 to 20 - for use in medium brightness daylight and twilight

Over 30 - for use in any light (exception - total darkness).

Another key factor in choosing binoculars is their magnification. Everything is quite simple here. It is selected according to individual needs.

Magnification - the degree of magnification, indicating how many times visible objects increase when viewed through binoculars. Models up to 10x, 16x – 20x and over 20x

Some modern binoculars are filled with gas. This is necessary so that the optics do not fog up during strong temperature changes. So if you are going to hot or, on the contrary, cold regions, it is better to choose binoculars with gas. There are also models with a special coating called - phase correction. It is responsible for improving the sharpness of the picture and takes place in expensive models.

One of the important technical nuances is the diameter of the exit pupil. This is the diameter of the light flux that exits the eyepiece directly into the pupil. Let's explain. If this diameter is 4 mm, and the pupil diameter is 5 mm, then the image will be fuzzy. The fact is that depending on the level of illumination, the diameter of the pupil can change (in the light it is smaller, in the dark it is larger). Therefore, if you need binoculars for use in poor lighting conditions, you should choose a model with a large exit pupil (6-7 mm). It is very easy to calculate it. You need to divide the diameter of the lens by the magnification. So for binoculars with characteristics of 10x50, the diameter of the entrance pupil will be 5 mm.

If you wear glasses, then eye relief must also be taken into account. This is the distance between the pupil and the eyepiece at which focus is still maintained. For viewing with glasses, it must be at least 15 mm. There are also binoculars for spectacle wearers on the market.

The ease of use of binoculars is affected by the ability to adjust the interpupillary distance. As you might guess, this is the distance between the pupils of an adult. Given the anatomical features, it is different for everyone. Therefore, most binoculars allow you to adjust it in the range from 60 to 72 mm.

Optical schemes of binoculars

The optical scheme is the design difference that largely determines their technical performance, as well as cost. There are 2 optical schemes:

Differences between optical schemes Roof and Porro

Roof. These binoculars are designed in such a way that the prisms, the eyepiece and the lens itself are on the same line. This allows you to significantly reduce the size of the device, and also provides better color reproduction. The disadvantage of such binoculars is that their optics are quite complex and expensive. Plus, expensive coatings and materials are used. Nevertheless, the best binoculars are made in this way.

Porro. This is a traditional scheme in which the distance between the eyepieces is less than the distance between the lenses. The design of these binoculars is such that the lens and the eyepiece are located on different axes. This significantly increases the dimensions of the device, but makes it cheaper. Most general purpose binoculars use the Porro pattern.

Take care of your eyesight

Often, when choosing binoculars, people forget that this is the same optical device as banal eyeglasses. Therefore, it can be both safe and harmful. Low-cost models with low-quality optics will not be able to provide high-quality focusing and correct image transmission. Prolonged use of such optics can lead to headaches and even nausea, and in the long term - deterioration of vision. In the case of binoculars, the miser can really pay twice: once for the device, and the second for vision correction.

For the same reason, I would like to mention children's binoculars. Often parents consider it just a toy, but the child is likely to look at it very often. Therefore, treat the choice of such a device responsibly.