Comparison BRESSER Corvette 10x50 vs BRESSER Hunter 8x40

The magnification factor indicates how many times the image of any object in the eyepiece will be larger than what is visible to the naked eye. Standard values are 7x, 8x, 10x, 12x, 20x. The higher the magnification, the greater the degree of approximation and the further the distance from which one or another object can be seen through binoculars. On the other hand, increasing the magnification usually means decreasing the angle of view, and it can be very difficult to “catch” an object of interest (especially a moving one) through binoculars. In addition, with the same lens size, a model with a higher magnification will have a smaller exit pupil size and, accordingly, a lower aperture ratio (see below for more details). For models with multiplicity adjustment (see below), this item usually indicates the maximum value of this parameter. The magnification is the first number in traditional markings like 8x40 - this example corresponds to eight-fold optics. If there is a multiplicity adjustment (see below), the markings indicate the entire range - for example, 8-12x40.

The diameter of the area visible through binoculars / monoculars from a distance of 1 km — 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". Along with the angular field of view (see below), this parameter characterizes the space covered by the optics; at the same time, it describes the capabilities of a particular model more clearly than data on viewing angles. Models with magnification adjustment (see above) usually indicate the maximum field of view — at the lowest magnification and the widest angle of view. This information is often supplemented by data on the minimum value.

The smallest distance to the observed object, at which it will be clearly visible through binoculars / monoculars. All such optical instruments were initially created for observing remote objects, therefore, not all of them are able to work at short distances. When choosing a model for this parameter, one should proceed from the expected observation conditions: ideally, the minimum focus distance should not be greater than the smallest possible distance to the observed object.

A complex indicator that describes the quality of binoculars / monoculars at dusk — when the illumination 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 through binoculars is determined primarily by the magnification of the optics, and in night light, by the diameter of the lens (see below); 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 8x40 binoculars, the twilight factor will be the root of 8x40=320, that is, approximately 17.8. In models with power adjustment (see above), the minimum twilight factor is usually indicated at the lowest magnification, but data is often given for the maximum. 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 lenses and prisms, the use of antireflection coatings, etc. Therefore, the actual image quality at dusk for two models with the same twilight factor may differ markedly.

The lens diameter is the front lens of the binocular/monocular. This parameter is also called "aperture". Designate it in millimetres. Aperture is one of the most important characteristics of an optical device: it describes the amount of light that the device is able to "capture" into the lens, and largely determines the image quality in low light. Therefore, the second number in the traditional marking of binoculars / monoculars is precisely the diameter of the lens — for example, 8x40 mm corresponds to 8x binoculars with an aperture of 40 mm. In addition, with a large lens it is easier to provide a wide field of view without sacrificing magnification. In general, the larger the aperture, the more advanced the optical device is considered. On the other hand, the increase in lenses has a corresponding effect on the weight and dimensions of the entire structure. And you should not forget about the influence of individual components of the system (for example, prisms) on the overall image quality.

Coating is a special coating applied to the surface of the lens. This coating is intended to reduce light loss at the air-glass interface. Such losses inevitably arise due to the reflection of light, and the antireflective coating “turns” the reflected rays back, thus increasing the light transmission of the lens. In addition, this function reduces the amount of glare on objects visible through binoculars/monoculars. There are single-layer, full single-layer, multi-layer, full multi-layer. More details about them:

- Single layer. This marking indicates that one or more lens surfaces (but not all) have a single layer of anti-reflective coating applied to them. This is inexpensive and can be used even in entry-level optical instruments. On the other hand, it filters out a certain spectrum of light, which distorts the color rendition in the visible image - sometimes quite noticeably. In addition, in this case, on some lens surfaces there is no coating at all, which inevitably leads to glare in the field of view. Thus, single-layer coating is the simplest type and is used extremely rarely, mainly in budget models.

- Full single layer. A variation of the single-layer coating described above, in which an anti-reflective coating is present on all surfaces of the lenses (at each air-glass interface). Although this option is al...so characterized by color distortion, it is devoid of another, the most key drawback of “incomplete” enlightenment - glare in the field of view. And the mentioned color distortion is most often not critical. With all this, full single-layer coating is relatively inexpensive, which is why it is very popular in entry-level and entry-mid-level models.

- Multi-layered. A type of coating in which multiple layers of reflective coating are applied to one or more lens surfaces (but not all). The advantage of such a coating over a single-layer coating is that it uniformly transmits almost the entire visible spectrum and does not create noticeable color distortions. The absence of a coating on individual surfaces reduces the cost of the device (compared to full multi-layer coating), but it is impossible to completely get rid of glare in such a system.

- Fully multi-layered. The most advanced and effective of modern types of coating: a multilayer coating is applied to all surfaces of the lenses. This way, high brightness and clarity of the “picture” is achieved, with natural color rendition and no glare. The classic disadvantage of this option is its high cost; Accordingly, full multi-layer coating is typical mainly for high-end models.

Interpupillary distance adjustment range provided in binoculars with the corresponding function.

Recall that, ideally, the interpupillary distance of the device should correspond to the distance between the centers of the pupils of the user himself. With this calculation, it is worth choosing binoculars according to this parameter; and if the device will be used by several people, it is worth making sure that they all “fit” into the adjustment range of the selected model. However, not every person knows exactly their interpupillary distance, especially since it changes with age; and the circle of users can be indefinite — for example, if we are talking about "rolling" binoculars in the hunting industry. In such cases, it is worth proceeding from the following.

In adults of more or less standard physique, the interpupillary distance is in the range from 60 to 66 mm. Modern binoculars cover this range with a margin — even the most modest models support values from 60 to 70 mm, and in most cases the lower limit of the range lies in the region of 54 – 57 mm, and the upper one — 72 – 75 mm. This is quite enough for most adults, including those with a non-standard physique — miniature, or vice versa, large. So a wider range may come in handy only in special cases. For example, if a child will use binoculars, it is desirable that the lower adjustment limit be lower than the standard 50 – 55 mm (in some models, this limit is at the level of 38 mm, or even 34 mm).

The presence of a special gas in the body of binoculars / monoculars — usually nitrogen or argon. Due to its chemical inertness, such a gas does not oxidize internal parts (unlike the oxygen contained in the air). In addition, this function assumes the tightness of the case, which allows most of these binoculars to endure even diving under water (for more details, see "Dust and water protection"), and also protects the optics from the harmful effects of fog. All this has a positive effect on the reliability and service life of the device. In turn, the gas filler itself contains practically no water vapor — thanks to this, the lenses do not fog up from the inside, as happens with conventional models during temperature changes.

The body of the binocular / monocular is protected from dust and moisture. You should pay attention to such models if you plan to use the device in nature — while hiking, hunting, fishing, etc. The degree of such protection can vary, from splash resistance to water immersion; this point should be clarified according to the official characteristics. Also note here that most of the "waterfowl" models usually have gas filling (see above), and the absence of such filling, usually, indicates low moisture resistance.