Comparison Aimpoint CompM4 vs EOTech HWS EXPS3-0

— Closed. Devices in a closed case, often also sealed. Classical optics, "night lights" and thermal imagers (see "Type"), by definition, use only this design. But collimators can also be open (see below), so only this type makes sense to compare by this parameter. With such a comparison, the main advantage of closed collimators can be called good protection from dirt, dust and accidental contact with foreign objects. In addition, the reticle in the closed housing is clearly visible even in bright ambient light; and in some models there is even the possibility of installing additional accessories, such as hoods, filters and flip-up protective covers. On the other hand, such sights are somewhat more expensive than open ones and more restrict the field of view for the working eye — a fairly significant part of the view is covered by the case.

— Open. A type of construction found exclusively in red dot sights (see "Type"): a single lens mounted in a special frame. Such models are more compact, lighter, simpler and cheaper than closed ones, and the frame is usually made thin and almost invisible to the shooter's working eye. On the other hand, open sights are more sensitive to dirt and damage, and under bright sunlight they can "go blind" — the brand becomes hardly noticeable. In general, this option is recommended mainly for "fast" shooting, when the speed of aiming and maximum control of the situatio...n are critical, first of all; for relatively calm situations, closed collimators are better suited.

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 type of aiming mark (reticle) provided in the device. There are models for which several options are indicated at once: this implies the possibility of switching between them.

As for specific varieties, in collimators, all brands have a common specificity - they should provide the convenience of quick aiming at relatively short distances. But the reticles of optical and other similar sights can be divided into hunting and tactical (sniper) sights. The former are relatively simple and have a minimum of additional elements, as they are designed for short distances and relatively large targets; and the latter are designed for high-precision shooting, military and police use, and therefore must be supplemented with various elements for measuring angles and taking corrections on the go, including between shots.

Among the specific types of grids most popular in our time are the cross with divisions, BDC, duplex, cross, half-cross, cross with a dot, cross with a circle, herringbone, rangefinder, dot, circle with a dot and circle with 2 points. Here are th...e main features of each:

— Cross with divisions. One of the most popular types of "tactical" reticles used in optical sights. The key element is the crosshair, on the lines of which additional dots are applied. The distance between the points corresponds to a strictly defined angular size; initially it was 1 MRAD (1 "mil", hence the name), however, in modern sights, other values \u200b\u200bcan be found, they should be specified according to the instructions. In addition, such grids can differ in the number of points, the presence of thickening on the lines (as in the duplexes described below), etc. Be that as it may, such a grid is very convenient for estimating distances and making corrections on the fly, many professional shooters consider it almost ideal for high-precision shooting, including at long distances, besides, the original cross with divisions (Mil-Dot) is widely used by military and police snipers around the world.
We also note that there is also a collimator variety of "mildots" - in this case, the grid looks like a circle with a dot in the middle and several dots below it, with an interval of the same 1 MRAD. However, when using collimators, the real need for making vertical corrections rarely arises, and this option is not widely used.

- Duplex. Reticles for optical and night sights (see "Type"), which look like a classic crosshair with different line thicknesses: they are thin in the center, and noticeably thicker near the edges. The meaning of this combination is that thin lines do not “clutter up” the field of view at the aiming point, and thick lines remain visible even under adverse conditions (for example, at dusk) and allow you to aim at least approximately. In addition, the thickness of large lines and the distance between their edges can correspond to well-defined angles, which allows some of these sights to be used even as simple goniometers. However, these possibilities are very limited, and in general, "duplexes" are classic hunting nets.

- Half cross. Hunting net, the main elements of which are T-shaped. One of the varieties of semi-crosses - "German grid", it is also "stump" - consists of a vertical line from the edge to the center of the sight and two horizontal lines that do not reach it; the aiming point corresponds to the upper point of the central "stump", and the thickness of the lines and the distance between them can be specified in the documentation - this allows you to carry out the simplest measurements of angles. A more modern version of the half-cross is the crosshair, in which one line (from the center to the top edge) is much thinner than the rest, or even absent altogether.

- Dot. In its pure form, the dot is used exclusively in collimator sights (see "Type"). This is an extremely convenient option for such devices: there are no unnecessary details in the field of view of the shooter, only a mark that clearly shows exactly where the weapon is aimed - more is often not required when using collimators. The disadvantages of the dot in comparison with other marks in the sights of this type include less visibility, especially in bright ambient light. However, many sights allow you to set a fairly high brightness of the mark, and sometimes even increase its size, increasing visibility. Also note that for a point, the angular size can be specified, which can be useful for quick estimation of distances.
In addition, the dot can also be used in optical and night sights, but in such cases it is usually used as an addition to another scale - for example, it additionally highlights the intersection of lines in a semi-cross.

— Circle with a dot. Another type of marks, used in collimators as the main one, and in other types of sights - as an addition to a crosshair or other more traditional grid. However, the latter is rare, so let's focus on the first option. Compared to another popular "collimator" mark - a dot - the circle covers more visible space, however, it is very noticeable and often turns out to be more convenient when shooting offhand or sharply turning the weapon to the side. In addition, for both the circle and the dot, it often indicates the exact angular size, which gives extended (compared to the usual dot) possibilities for using the aiming mark as the simplest goniometric (rangefinding) scale.

- Circle with 2 dots. A variation of the circle with a point described on top, having a second, additional point - usually below the first, at a strictly defined angular distance from it. This expands the possibilities for using the sight as an impromptu rangefinder, and also allows you to "on the move" take an amendment when shooting at long distances - just aim at the second, lower point. However, such opportunities for collimators are extremely rarely required, so this option has not received much distribution either.

- Cross. Features of this type of brand depend on the type of sights in question - optical / night or collimator (see "Type"). In classical optics, a cross is the simplest crosshair of thin lines of the same thickness. Naturally, in terms of general specialization, such reticles are hunting, but they are also found in a fairly advanced variety of sights - sports models for benchrest (shooting from a machine gun at maximum range and accuracy). The convenience of the cross in such an application lies in the fact that the lines have a minimum thickness and practically do not block the view. In nightlights, this type of grid is usually one of several options available to choose from. But in collimators, the cross is in many ways similar to a circle with a dot - it is provided as one of the large, well-marked marks with a clearly defined angular size.

- Cross with a dot. A grid in the form of a crosshair of two lines (as a rule, quite thin), at the intersection of which a clearly visible point is applied. It is in this form, as a rule, that is used in collimator and other types of sights. In the first case, such a stamp is actually a slightly modified version of the usual cross (see on top). And in optics, the presence of a point allows you to additionally highlight the crosshairs, which is convenient in some situations; the general purpose of such sights is, of course, hunting.

- A cross with a circle. Stamp in the form of a cross, complemented by a circle. It can also be used in different types of sights and has its own specialization everywhere. In classical optics, such a grid usually has a hunting purpose, although there are also varieties with additional marks that expand the "tactical" functions. And even in the absence of such marks in the characteristics, the angular size of the circle is usually specified, which provides additional opportunities for impromptu measurement of distances. We also note that the cross itself can be both ordinary and duplex (see on top). The situation is similar in night sights, however, there a cross with a circle is usually only one of the available mark options. As for the collimators, they can use both a full-fledged crosshair in a circle, and a ring with “rays” protruding from it; in any case, such a mark is more noticeable than an ordinary cross.

— BDC. This reticle got its name from the English phrase Bullet Drop Compensation, which translates as “bullet drop compensation”. The BDC ballistic reticle allows for range correction based on the bullet's trajectory. It is calibrated for a specific ammunition and sharpened for quick aiming at various distances using the same type of bullets. Distance markers in a ballistic reticle are hash marks, circles, or dots. The main sign of their placement is that the vertical markings have different gaps, increasing towards the bottom. An additional distance scale is often placed in such grids on the "six" shoulder. In addition, the ammunition for which the reticle is calibrated is usually indicated (caliber, bullet weight, weight).

- Christmas tree. Informative reticle resembling a Christmas tree in its structure. Actually, this is where the name of this type of grid came from. Each array of dots on its "six o'clock" arm is longer than the previous one - the marks increase in width when viewed from top to bottom from the central crosshair. These markers are used to correct for wind drift, which is extremely important when conducting aimed fire at long distances. The most common herringbone reticle is found in hunting hybrids, tactical sights, and military rifle scopes.

- Rangefinder. This type includes all grids that do not belong to any of the types described on top and provide for special markings for measuring angles and distances. The specific design of such markings may be different, but the general principle of operation is the same everywhere: rangefinder marks allow you to determine the angular size of a visible object, and if the linear size of this object is known, you can easily estimate the distance to it (at least approximately). Each type of rangefinder reticle has its own rules for use.

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.