Comparison Yajia YJ-2829 vs Yajia YJ-2805

The number of LEDs (see "Lamp type") provided in the design of the lantern.

At first glance, the more LEDs, the more powerful this model. However, in fact, things are not so clear cut. Firstly, one high-end LED may well provide more light output than several inexpensive diodes. Secondly, modern luminaires can use both traditional LEDs and arrays of numerous miniature diodes on a common basis. Such arrays can be implemented using SMD technology or more advanced COB; the differences between these options are described in more detail in the Diode Model section, here we note that a solid SMD or COB plate is also considered to be 1 LED — despite the fact that in terms of luminosity it can exceed conventional LEDs by several times, or even orders of magnitude.

Thus, it is hardly worth directly evaluating the brightness and efficiency of the flashlight by this parameter. But what the number of diodes often directly affects is reliability: most “repeatedly charged” lamps are able to continue working even if some of the diodes fail. In addition, in some types of flashlights — in particular, tourist models and hand-held diffused lamps (see "Type") — each LED illuminates a separate sector, and together they cover a full 360 ° horizontally.

The maximum luminous flux provided by the lantern.

Luminous flux (denoted in lumens) can be described as the total amount of light produced by an LED or other light source and distributed in all directions where this source shines by itself (without lenses, reflectors, etc.). In fact, this means that the capabilities of the flashlight depend not only on the luminous flux, but also on the angle of illumination (see "Angle of illumination (light)"). For example, a relatively weak stream can be concentrated into a narrow beam, providing good range; and a large number of lumens will inevitably be needed to effectively cover a wide area.

Note that the coverage angle is not always specified in the characteristics, and even with such data it is difficult to immediately assess the real capabilities of the flashlight. Therefore, for such an assessment, it is best to use information about the actual illumination range (see below), and also take into account the general type of device (see above). For example, for the same number of lumens, a handheld flashlight with a reflector to form a directional beam will give a noticeably greater range than a tourist lamp with 360 ° coverage.

It should also be borne in mind that the high brightness of the flashlight is far from always justified, and it is worth choosing according to this parameter, taking into account the actual conditions of use. S...o, when working at short ranges, bright light can become a hindrance: it tyres the eyes and can blind others. In addition, an increase in brightness usually requires more powerful sources of both light and power, and the weight and dimensions of the lantern increase accordingly.

The maximum range at which the flashlight provides any effective illumination of objects. Different manufacturers have different criteria for this efficiency when measuring ranges, and therefore it is only possible to unequivocally compare among themselves in range only models of one manufacturer. At the same time, this parameter allows us to compare models from different manufacturers with some certainty: for example, flashlights with a lighting range of 15 m and 100 m will clearly belong to different range classes, regardless of manufacturers.

Note that the range of illumination depends not only on the maximum luminous flux provided by the lantern (see above), but also on the features of its design: the narrower the beam is provided by the reflector of the lantern, the greater the range will be, and vice versa — scattered light does not spread far. Some models allow you to adjust the beam width depending on the requirements of the situation (for more details, see "Adjusting the focus").

It is also worth bearing in mind that models with the same claimed lighting range can cover different spaces. For example, a hand lamp (see Type) with a reflector diameter of 20 cm will be able to provide a wider beam than a conventional hand lamp with a 5 cm reflector. And although in both cases the objects that fall into the light spot will be illuminated in the same way, however, in the first case, the size of the spot itself will be larger, and the actual efficien...cy of the flashlight will be correspondingly higher (in light of the fact that it is easier to "feel" individual objects with a wide beam, especially at a considerable distance).

The number and types of additional modes of operation provided for in the flashlight.

Additional modes include all modes in which the flashlight operation format differs from the standard “constant luminous flux in the visible range without pronounced coloration”. Namely strobe, SOS, beacon, flicker, light, low / high beam, infrared (IR), ultraviolet (UV), red light, blue light, green light, etc. More details about each:

- Stroboscope. Fast flashing mode - several flashes per second. One of the most popular applications of this function is disorientation of the enemy in an extreme situation; in light of this, a stroboscope is often provided in underbarrel flashlights (see "Type"), as well as manual models of "tactical" specialization. In addition, fast blinking is well suited to distinguish yourself on the road - especially in cloudy weather or at night: such a light is much more visible than constant light, including with peripheral vision. At the same time, we note that when using a stroboscope, some caution should be observed: due to the specific effect on the p...syche, this mode can provoke exacerbations of certain diseases - for example, seizures in patients with epilepsy.

— S.O.S. The mode of operation is "three short flashes - three long - three short", which corresponds to the international signal "please help" (letters SOS in Morse code format). This eliminates the need to send such a signal manually and allows you to leave the flashlight to work autonomously, and take care of more pressing problems (which often accompany situations that require the "SOS").

— Low / high beam. Possibility to switch between far directional beam and near diffused light. This switching is most often accomplished by using multiple sets of LEDs; at the same time, in some models, each of these sets is responsible for its own mode, in others, all diodes work in the high beam, and only a part of them work in the low beam.

— Infrared (IR). Illumination in the invisible infrared range. It is used, in particular, to improve the efficiency of night vision devices and IR sights. Note that many of the LEDs responsible for this mode also glow in the visible range (red light) during operation; however, this glow is quite weak and, as a rule, is noticeable to the human eye only when looking directly at its source from a short distance.

- Ultraviolet (UV). Illumination in the ultraviolet range is mainly used to identify objects and traces that are invisible under normal lighting. One of the most popular ways to use this feature is with a makeshift currency detector: most modern banknotes have markings that glow under UV light. Also, such light can be used to detect inscriptions with “invisible” ink (including marks on the same banknotes), some biological (for example, blood) and chemical liquids (in particular, UV-sensitive compounds can detect leaks in pipes and liquid contours), etc. Note that the UV emitter usually glows in the visible range - with a characteristic bluish tint; this allows you to accurately determine whether such a light is on or off.

- Red light. One of the more popular complementary colors in modern flashlights; can be used both in combination with blue and green (in the so-called RGB models), and as the only auxiliary shade. One of the features of red light is that it practically does not affect night vision, does not penetrate through the eyelids, and even after complete darkness does not blind the eyes. This makes such lighting the best option, for example, for clarifying map data during a night hike, when you need to quickly restore vision after turning off the light, or for emergency lighting in a sleeping room, where you need to see the environment and at the same time it is undesirable to disturb sleeping people with the light. . Another way to use red light is signaling: this light travels farther than blue or green, and stands out prominently against most landscapes and man-made objects. Hue change can be carried out both due to the light filter on the main light source, and due to a separate LED.

- Blue light. One of the shades used in the main three-color "RGB-lanterns" - along with red (see above) and green. This light is intended mainly for situations where you need to effectively illuminate the space in front of you, but it is undesirable to use ordinary white light. Human vision is most sensitive just to blue and green shades; therefore, a relatively weak blue light flux allows a large amount of detail to be revealed. And in some situations, such lighting can be even more effective than white. For example, if at night a white lantern is pointed at a light object, then the space behind this object will be hardly noticeable due to the bright reflected light; and a weak blue light will evenly highlight both the "foreground" and the "background". But using this shade at high brightness, on the contrary, is undesirable - reflection from bright blue light will dazzle even more than from white, and even more so red. And if a blue beam, even a weak one, hits directly into the eyes, it will instantly knock out night vision, and it will take quite a long time to restore it.
Note that the choice between blue and the similar green (see below) depends on the specific situation: different shades may be optimal in different situations.

- Green light. Hue, most commonly used in tri-color RGB lights, but sometimes used as the only complementary color. In many ways it is similar to the blue described above - in particular, in some situations, a weak green light can clearly reveal details that are invisible in other shades (even under the same blue light), but high brightness is undesirable for such a beam. In addition, this color has its own specific feature: many animals almost do not react to green light, so it is especially convenient for hunting.

- Lighthouse. The mode of infrequent flashes with a repeating amplitude, most often at a relatively low brightness (with some exceptions to the rule). In some models of lanterns, you can even meet more than one version of the lighthouse. The mode is designed to detect and observe the user at a distance; at the same time, the beacon not only consumes battery power more economically than a constant light of the same brightness, but is also better visible from afar. We also note that in headlamps, the flicker mode performs a similar function (see below).

- Flicker. In this mode, the flashlight emits short pulses or shines with a variable, "pulsating" brightness. This format of work is not intended to illuminate the surrounding area, but to make the user more visible to others: a person reacts to flickering light reflexively, even if its source is far in the peripheral vision zone. The flicker mode will be useful primarily on the roads - for example, when walking or cycling at night: in the same city, such a warning for surrounding drivers will not be out of place, and there is no need to talk about dark country roads.

— Red blinking (red blinking, red beacon). This mode allows you to make the flashlight as noticeable as possible: the red light, especially the flashing one, catches the eye even in the daytime. And in the dark, this shade is also useful due to the fact that it does not harm night vision (for more on this, see "Red Light" above). But the specific specialization of the red flashing may be different, depending on the specialization of the flashlight. For example, in tourist models (see "Type"), this mode allows you to give a signal, indicate the location of the camp, collection points, etc.; and in headbands, it is used to highlight the user on the road and make him as visible as possible to others (primarily for car drivers).

- Lamp. The function is found, as a rule, among hand lamps and in tourist models of flashlights (as an addition to the main directional light). In fact, we are talking about a scattered light mode - as opposed to a directional beam that provides the main light source with a reflector. Diffused light does not differ in range, but it allows you to cover a significant space - for example, to illuminate an entire room.

- LCU. Laser pointer mode: the flashlight emits a laser beam, the mark from which points to the intended point of impact. It makes sense to provide for such a regime only in underbarrel models (see "Type").

Note that this list is not exhaustive: modern flashlights may provide for other, more specific modes of operation. In such cases, the features of the functionality should be clarified according to the manufacturer's documentation.

The time to fully charge the battery, which is equipped with a flashlight, from a standard charger (when using other batteries or a "non-native" charger, this time can vary both in one direction and in the other direction).