Comparison Vortex Razor AMG UH-1 Gen II Holographic Sight vs EOTech HWS EXPS3-0

Collimator sights (see "Type") using the holographic principle of operation.

In such models, the aiming mark is projected not by the classic system of lenses and mirrors, but by a laser LED and a special holographic grating. This significantly increases the cost, but gives a number of advantages over classical collimators. So, holographic sights are usually completely devoid of parallax (see "Detuning from parallax") - that is, the visible mark always remains clearly on the aiming point, regardless of the position of the working eye relative to the sight and the distance to the target. Lenses in such models have better light transmission and give less glare, which improves visibility. True, holographic sights are made predominantly open (see "Design"), however, their degree of protection is usually somewhat higher than that of traditional counterparts; in addition, the lens in such a collimator remains operational even with partial damage. The disadvantages of "holography", in addition to the price, include increased power consumption, which requires the use of more powerful and capacious batteries.

The diameter of the objective is the front lens of the sight. This parameter is also called "aperture".

This parameter is important primarily for optical sights and their specialized varieties — "night lights" and thermal imagers (see "Type"). The larger the lens, the more light enters it, the higher the image quality and the more efficient the device will work in low light, but the more expensive such optics will cost. It is worth noting here that the requirements for the aperture also depend on the degree of magnification: in other words, especially large lenses are not required for low magnifications. Therefore, relatively small entrance lenses, with a diameter of 25 – 35 mm and even less, are found in all price categories of classical optics — from low-cost to top. And you can compare by aperture only models with the same maximum magnification, and even then it’s very approximate — it’s worth remembering that image quality also depends heavily on the overall quality of the sight components.

In turn, for night sights, especially those based on image intensifier tubes (see "The principle of operation of night vision devices"), a large aperture is fundamentally important. So a diameter of 36 to 45 mm is considered very small for such devices and is found only in some digital models, while most nightlights are equipped with lenses of 46 mm or more.

As for collimators, the size of the space that enters the scope depends mainly on the aperture. Moreover, the actual visible size can be changed by setting the sight closer or farther to the eye — the principle of operation of collimators makes this possible. Note also that for models with lenses of a rectangular or similar shape, the size of the lens is usually indicated diagonally.

The diameter of the area visible through the sight from a distance of 100 m — in other words, the largest distance between two points at which they can be seen simultaneously from this distance. It is also called "linear field of view". This indicator is more convenient for many users than the angular field of view (the angle between the lines connecting the lens and the extreme points of the visible image) — it very clearly describes the capabilities of the device.

In sights with magnification adjustment (see above), both the entire range of width — from maximum to minimum — or only one value of this parameter can be indicated. In the latter case, the largest width of the field of view is usually taken, at the minimum magnification.

A type of coating used in scope lenses. Anyway, we are talking about the so-called antireflection coating, which is the thinnest film (single or multilayer) on the surface of the lens in contact with air. The properties of this film are chosen in such a way as to minimize the reflection of light from the glass surface. The meaning of this function is not so much to reduce the brightness of glare that can unmask the shooter, but to increase the light transmission of the optics and, accordingly, the quality of the image visible through it.

Modern sights can be equipped with the following types of coatings:

— Illuminating. In this case, the simplest option is implied — an incomplete single-layer coating. The term "incomplete" means that not all lens surfaces are coated (although there may be several coated surfaces). Such enlightenment is inexpensive, however, the image quality is relatively low — in particular, because a single-layer film is most effective only for a part of the visible colour spectrum.

— Full illumination. Fully coated means that all surfaces of the lenses that come into contact with air have a special coating; in this case it is single layer. Such a coating is more expensive than a simple anti-reflective coating, but the quality of the “picture” when using it is higher, because. light distortion at the transitions between glass and air is minimized.

— Multi-layered illuminating. Incomplete AR coating (see above)...using multilayer films. Thanks to multiple layers, the anti-reflective coating covers the entire visible spectrum, which allows you to achieve a brighter image with less colour distortion compared to single-layer coatings; However the price of such devices is higher.

— Full multilayer enlightenment. The most advanced option: multilayer coating on all lens surfaces used in the design of the sight. Features of full and multi-layer coating are described separately above. Here we note that their combination is typical for high-class sights, because. it provides the highest quality image, but it is not cheap.

The design of the drum (drums) for entering corrections, provided in the sight.

— Closed. Drums closed with threaded caps or other protective devices. This design does not allow you to quickly, on the go, make adjustments, but the regulators are maximally protected from foreign objects, and the likelihood of knocking down the settings in case of accidental contact with such an object is reduced to almost zero. This makes closed turrets perfect for scopes that are adjusted once, at initial zeroing, and then used at fixed settings; collimators and hunting optics for relatively short distances (up to 300 m) can be cited as an example.

— Open. Drums that do not have special protection — thus, you can turn such a drum immediately, only by stretching out your hand to it. Such regulators allow you to make adjustments “on the fly”, literally after each shot, making them very convenient for high-precision shooting, especially under constantly changing conditions; in particular, it is the open design that professional snipers use. As for the shortcomings, one can come across allegations that in case of accidental contact with a foreign object, the drum may turn, knocking down the settings. However, in modern sights, manufacturers take this possibility into account and prevent such cases — for example, due to a tight rotation mechanism or special drum fixation systems.

The type of power used in the scope, in fact, describes the type of autonomous element (accumulator or battery) that the device is designed for.

The most popular elements in modern sights are CR2032 elements — characteristic "pills" with a diameter of 20 mm and a thickness of about 3 mm. Their shape fits very well into the layout of both optics and classical collimators (see "Type"), and the capacity, although relatively low, is quite sufficient for normal operation for a long time, because the power consumption of these types of sights is low. But in more “gluttonous” night, thermal imaging (see ibid) and holographic (see above) models, more solid batteries are usually used — most often either a pair of standard “finger” AA cells, or a 3.7 V CR123 element (diameter 17.5 mm, length 35 mm). In this case, the sight can be compatible with either one of these types, or both. It is also worth noting that AA and CR123 elements are also available as rechargeable batteries, which can be perfect for frequent use of the scope.

Approximate time of continuous operation of the sight on one set of batteries or battery charge. It is indicated for some standard conditions, so the actual operating time may differ from the claimed one (especially since it also depends on the quality of specific batteries). At the same time, this parameter quite accurately characterizes the overall battery life of the device, and is also quite suitable for comparing different models with each other: for example, if twice as many hours are claimed for one collimator as for another, in fact, most likely, with other equal will work twice as long.

It should be noted that in optical sights (see "Type"), power is used only for additional functions such as reticle illumination. So for such models, this parameter is of secondary importance: in general, the optics remain fully functional even without batteries.

This feature automatically turns off the power after a certain period of time. Its general meaning is to save battery power — so that the sight does not "eat" energy in vain if the shooter forgets to turn it off. But the specific features of auto-shutdown in different models can vary markedly. So, in some devices, it occurs regardless of external factors, in others — only if the device has been in a stationary position for some time (in the first case, the time before shutdown is usually measured in hours, in the second — in minutes). Also note that there are sights with the ability to adjust the shutdown time.

The weapon class that this scope can be used with.

Different classes of weapons differ in the energy of the shot and, accordingly, the recoil force that the sight must endure without consequences. It is the maximum allowable energy of the shot (muzzle energy) that in this case is the main criterion for classifying the sight into one of the categories: light pneumatics, rifles and shotguns, large caliber. It is worth saying that such a division is somewhat arbitrary — see details in separate paragraphs; here is their detailed description:

— Lightweight pneumatics. Sights designed for weapons that practically do not give recoil — such as air PCP rifles, spring-piston “breaks” with muzzle energy up to 7.5 J, carbines chambered for Flaubert, as well as airsoft drives. Such models are definitely not suitable for firearms: they do not tolerate even the recoil from small-caliber rifles, not to mention more serious use. And even pneumatics have their limitations — in particular, powerful (more than 7.5 J) spring-piston models give significant returns with strong vibrations, and in pistols with the Blow-back system, noticeable concussions occur not because of the shot itself, but from -for the work of automation. So it is better to equip these types of weapons with more durable and reliable sights.

— Rifles and shotguns. Sights that can be used with...rifles of small and medium calibers, as well as smoothbore weapons (shotguns). They have a solid construction that allows them to endure rather strong recoil and accompanying vibrations without consequences, but the specific restriction on the allowable muzzle energy (and, accordingly, the calibers and ammunition used) may be different. However, scopes in this category are usually able to safely carry at least 2500 J — this is enough for rifled calibers 5.45x39, 7.62x39 and .223, as well as for 12-gauge rifle cartridges with a standard weight of gunpowder. And in many models, the maximum allowable energy can reach 3500 J and even 4000 J (the smallest values \u200b\u200bnecessary for full-fledged use with .308 and 7.62x54R calibers, respectively). At the same time, for reinforced magnum ammunition, as well as for some powerful (though not large) calibers, such a sight may still not be enough.

— Large-caliber. The most durable and reliable sights, designed for muzzle energy of 4000 J and above. Because of this, they can be used even with large-caliber firearms, as well as with some powerful calibers that are not formally large — for example, .300 Win and .338 Lapua Magnum. The specific restriction on muzzle energy, again, may be different, but if you are looking for a sight for a caliber more powerful than 7.62x54R or for reinforced rifle ammunition like 12x76, you should definitely pay attention to this category.

Separately, it is worth noting that “firearm” sights, even quite durable and reliable, are not recommended to be installed on pneumatics with a spring-piston mechanism or a gas spring. The fact is that such rifles have a specific recoil, directed forward rather than backward, moreover, giving sharp vibrations in different directions; and although the force of such recoil is low, it can still adversely affect the sight, which was not originally designed for it.