Comparison Pulsar Edge GS 1x20 vs Pulsar Edge GS 3.5x50L

The greatest distance at which a night vision device is capable of detecting individual objects.

The methods by which manufacturers determine this parameter may vary in detail, but the general principle is the same. Usually, the distance is indicated at which, with an illumination of 0.05 lux (a quarter of the moon) and a medium-contrast background, a rather large object can be seen — for example, a human figure with a height of about 170 cm is most often taken. of this object, but only to notice the very fact of its presence. Simply put, a detection range of, say, 200 m means that “something that looks like a person” can be seen in such a device at a distance of 200 m, but individual parts (head, hands) cannot be disassembled.

It is also worth noting that in fact this parameter is highly dependent on the characteristics of the situation. For example, a dark object on a very light background will be visible further, and on a dark one it may not be noticeable even up close; a similar phenomenon is observed for thermal imagers (see "Type"), only regarding the difference in temperature, and not in colours.

The degree of image magnification that a night vision device is able to provide without digital image processing, solely due to the optical system. Such an increase is considered to be preferable to digital, because. it does not impair the clarity of the visible image; and for models based on image intensifier tubes (see "How it works"), this is generally the only available option.

Theoretically, the higher the magnification, the greater the detection range (see above), since a powerful increase allows you to see smaller objects. However, it does not always make sense to chase the maximum performance. The fact is that with increasing magnification, the angular field of view decreases and the minimum focus distance increases (see both below), which can create problems at close range. It is also worth noting that a high degree of magnification adversely affects the luminosity of the entire system — as a result, the actual detection range in complete darkness may be higher for a device with a lower magnification, because. it "catches" more light. Yes, and this parameter affects the cost accordingly.

Note that night vision devices, unlike classical binoculars and monoculars, most often have a fixed magnification. Models with the possibility of smooth adjustment are almost never found, and the only option is to use additional nozzles (see "Form factor").

Now on the market are night vision devices with the following optical zoom: 1x, 2 – 3x, 3.1 – 4x, > 4x

The diameter of the entrance lens that the lens of the night vision device is equipped with.

This parameter is one of the most important for any optical device, including night vision devices: the larger the lens, the more light (or infrared radiation) enters it and the more sensitive the optics are, all other things being equal. The downside of this is an increase in the size, weight and cost of the device. In addition, do not forget that various tricks and additional technologies can be used in the design; therefore, by itself, a large lens is far from always an unambiguous indicator of a high class.

The angle of view provided by a night vision device — that is, the angle between the lines connecting the observer's eye with the two extreme points of visible space. Wide viewing angles allow you to cover a large area, but the magnification factor (see above) is low; in turn, increasing the magnification leads to a decrease in the field of view.

The smallest distance to the observed object, at which it will be clearly visible through the night vision device. For normal use of night vision devices, it is necessary that this distance does not exceed the minimum expected distance to the objects in question; thus, it must be borne in mind that the higher the magnification factor (see above), the greater the focus distance, usually.

The wavelength of infrared radiation emitted by the IR illuminator installed in the night vision device. In most cases, this parameter is purely reference: manufacturers usually select the wavelength in such a way that it best suits the features of the device and provides the claimed characteristics. Nevertheless, a practical moment is also associated with the wavelength — the "visibility" or "invisibility" of the illuminator (see "Invisible radiation spectrum").

The presence in the design of night vision devices of an IR emitter(see above), operating in a completely invisible spectrum.

One of the features of modern lighting devices (including infrared ones) is that none of them is capable of producing waves of exactly the same wavelength — some part of the radiation will inevitably capture neighboring ranges. Because of this, situations arise when the illuminator, the main power of which is concentrated in the IR spectrum, also emits visible light. It looks like a dim red glow; it is not strong enough to illuminate surrounding objects to the naked eye, but is clearly visible in the dark and can unmask the user. Radiators with an invisible spectrum, as the name implies, do not have this drawback. Therefore, if you are looking for night vision devices for situations in which stealth is important — for example, for hunting — it makes sense to choose among models with this function. However note that the illumination range of such emitters is somewhat less than that of visible ones.

Usually, "invisible" emitters have a wavelength (see above) of at least 800 nm.

The presence of a helmet-mask in the delivery set of the night vision device.

The helmet-mask is a hoop with a system of belts and a mount for the device. This design allows you to wear night vision devices on your head, due to which your hands remain free when working with the device. At the same time, the thickness of the hoop and belts is usually small, which allows them to be worn under a headdress.

It should be noted that the possibility of installation on a helmet-mask is found in many NVG models, however, the helmet-mask itself is far from always supplied in the kit. Buying it together with the device is much easier than picking it up separately.