Comparison Vector Optics VictOptics C3 3-9x32 SFP vs Leapers UTG BugBuster 3-9x32 AO

The offset is the distance between the eyepiece lens and the exit pupil of an optical instrument (see "Exit Pupil Diameter"). Optimum image quality is achieved when the exit pupil is projected directly into the observer's eye; so from a practical point of view, offset is the distance from the eye to the eyepiece lens that provides the best visibility and does not darken the edges (vignetting). A large offset is especially important if the sight is planned to be used simultaneously with glasses — after all, in such cases it is not possible to bring the eyepiece close to the eye, and it must be at some distance from the glasses so as not to hit the glass due to recoil.

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 complex indicator that describes the quality of any optical system (including sights) at dusk — when the lighting is weaker than during the day, but not yet as dim as in the deep evening or at night. It is primarily about the ability to see small details through the device.

The need to use this parameter is due to the fact that twilight is a special condition. In daylight, the visibility of small details is determined primarily by the magnification of the optics, and in night light, by the diameter of the lens (see above); at dusk, both of these indicators affect the quality. This feature takes into account the twilight factor. Its specific value is calculated as the square root of the product of the multiplicity and the diameter of the lens. For example, for an 8x40 scope, the twilight factor would be the root of 8x40=320, which is approximately 17.8. Models with adjustable magnification (see above) usually indicate the minimum twilight factor corresponding to the minimum magnification.

The lowest value of this parameter for normal visibility at dusk is considered to be 17. At the same time, it is worth noting that the twilight factor does not take into account the actual light transmission of the system — and it strongly depends on the quality of the lenses, the use of antireflection coatings (see below), etc. Therefore, the actual image quality at dusk for two models with the same twilight factor may differ markedly.

One of the parameters describing the quality of visibility through an optical device in low light conditions. Relative brightness is denoted as the diameter of the exit pupil (see above), squared; the higher this number, the more light the sight lets through. At the same time, this indicator does not take into account the quality of the lenses and their coatings used in the design. Therefore, comparing two sights in terms of relative brightness is only possible approximately, because even if the values are equal, the actual image quality may differ markedly. Also note that it makes sense to pay attention to this parameter only if the sight is planned to be used at dusk.

As for specific values, in the "dimest" models, the relative brightness does not exceed 100, in the most "bright" it can be 300 or more. Detailed recommendations regarding the choice of this parameter for certain conditions can be found in special sources. Here it is worth mentioning that the relative brightness is not directly related to the price category of the sight: models similar in this indicator can vary significantly in price.

The possibility of manual adjustment of the sight from parallax, by the user himself. For this purpose, the design provides a corresponding regulator.

Parallax in this case is a phenomenon when, when the eye deviates from the optical axis of the sight (from the center of the eyepiece), the aiming mark visible to the shooter also shifts, while the sight itself remains motionless. As a result, if the eye is not exactly in the center, the visible position of the mark does not coincide with the actual aiming point. This phenomenon is especially pronounced in optical sights (see "Type"), and many collimators are also subject to it, although not to the same extent (but "night vision" and thermal imagers are free of this drawback, since the mark is displayed on the built-in display).

To eliminate this phenomenon, a specific adjustment is used - parallax adjustment. It is usually done right at the factory. However, the sight can be adjusted from parallax only for a certain distance, and with significant deviations from this distance (more than 30% downwards or 60% upwards), this effect begins to manifest itself again. It can be compensated for by an ideal insert ("eye strictly in the center"), but even for experienced shooters this can be difficult, especially when shooting standing, offhand and in other uncomfortable positions. In light of this, some models also provide manual parallax adjustment - a regulator that allows you...to set the adjustment distance at the user's discretion. In addition to the situations described above, this function will be especially useful for novice users, as well as for high-precision shooting at long distances.

Optical sights with parallax adjustment> can be equipped with a wide ring on the AO (Adjustable Objective) lens or a drum on the SF (Side Focusing) control unit, on which additional accessories for fine-tuning the focus in the form of wheels are installed.

The scope has a zero adjustment function. This function is used during the initial sighting of optical sights (see "Type") for a specific rifle and ammunition, and later it greatly simplifies the work with vertical and horizontal corrections. Its essence is as follows

The process of zeroing in optics, roughly speaking, is the selection of such a position of the drums, in which at a distance of 100 m the sight ensures a clear hit at the aiming point (taking into account the spread of the weapon, of course). Such settings are taken as zero, it is from them that all further corrections are counted. However, the scales of the drums already show certain values by the time they are brought to this position — because of this, when you subsequently enter corrections, you can get confused in the number of clicks, make a mistake when returning the sight to its original settings, etc. The zero setting solves the problem: after zeroing, it is possible to rearrange the scales of the drums to the zero position without knocking down the settings of the adjusted sight. Thus, all subsequent corrections of the hands will be able to count from zero values on the scale, and to return to the original settings, it is enough to return the drums to the same zeros.

The specific method and features of such a setting may be different, usually, they are described in detail in the instruction manual. Here we note that this function is highly desir...able for sights used in high-precision (sniper) shooting, where you have to work a lot and often with amendments.

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 location of the reticle in the optical sight (see "Type").

Such a grid can be installed either in the first focal plane, FFP(roughly speaking, in the lens area), or in the second, SFP(in the eyepiece area). At the same time, for sights with a fixed magnification, the difference between these options is only in price, so they use only the simpler and cheaper SFP. But in models with multiplicity adjustment, this parameter directly affects the application features, and we will analyze this difference in more detail:

— In the 1st focal plane (FFP). The key advantage of reticles in the first focal plane is that their apparent size also changes in direct proportion with a change in magnification. In fact, this means that the angular dimensions of the individual mesh elements remain the same regardless of the set magnification. That is, for example, if a distance of 1 MRAD is claimed between two neighboring points, then it will be 1 MRAD in the entire range of multiplicity adjustment. This means that you can work with the grid for measuring distances and taking corrections according to the same rules, regardless of the selected degree of increase. Thus, FFP sights are much more convenient and easier to use than SFP. On the other hand, such models are noticeably more complex and expensive; and many hunting reticles — for example, a duplex or a classic cross (see "Reticle Type") — it makes...no sense at all to install in the first focal plane. In light of all this, this option is relatively rare and only in mid-range and top-level models designed for high-precision shooting.

— In the 2nd focal plane (SFP). The most common reticle placement option, including variable magnification sights. Such popularity is primarily due to the simplicity of design and low cost. However, the reverse side of these advantages are additional difficulties when using goniometric mesh elements. The fact is that in SFP sights, the apparent size of such elements remains unchanged when the magnification changes, which means that the dimensions of individual parts at different magnifications will correspond to different angles. More precisely, the angular dimensions in such systems change in inverse proportion to the multiplicity: for example, if at a multiplicity of 5x the distance between two adjacent points is 6 MOA, then at 15x it will decrease to 2 MOA. Thus, the “true” angular size indicated in the characteristics, the marking elements have only at a strictly defined multiplicity, in other cases, this size must be recalculated using special formulas. At the same time, it is worth noting that if the grid does not have special goniometric elements, then this disadvantage becomes practically irrelevant for it; examples are hunting nets of the "half-cross" type (traditional, not "stump") and "cross with a circle" (see "Net type").

Units of measurement that are used in the marking of goniometric elements of the reticle. In our time, there are two main units: - MOA. The abbreviation for minute of arc is 1/60 of a degree. Initially, this unit is associated with the English system of measures and is convenient primarily for calculations in yards and inches: at a distance of 100 yards, an angle of 1 MOA corresponds to a linear dimension of approximately 1 inch. In the more familiar metric system for us, this gives 2.91 cm at a distance of 100 m. We also note that this unit is a kind of accuracy standard: it is believed that a full-fledged sniper rifle should give a spread of no more than 1 MOA.

— MRAD. Conventional designation miradian - an angle of one thousandth of a radian (approximately 0.06 °). Also in the jargon of snipers, this unit is called "thousandth", or "mil". It is already tied to the metric system: at a distance of 100 m, an angle of 1 MRAD corresponds to a linear size of 10 cm (approximately 3.5 times greater than 1 MOA).

The choice for this indicator largely depends on the personal preferences of the shooter. We also note that inconsistencies are often found in low-cost sights: their drums are marked on the MOA scale, and the reticle is in MRAD units.