Max. luminous flux
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.Lighting range
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).
Max. operating time
Maximum runtime of the flashlight without changing batteries or recharging the battery.
Note that in models with brightness control, this time is indicated for the most modest and, accordingly, economical mode. For example, in a flashlight with a maximum luminous flux of 1000 lm, the claimed operating time of 20 hours can be achieved at a brightness of only 30 lm, and at maximum battery life may not exceed half an hour. These nuances should be clarified according to the detailed characteristics. However, also note that additional modes of operation (see below) are not taken into account in this case: for example, if the flashlight from our example in SOS mode can operate for 30 hours, the characteristics will still state 20 hours.
It is also worth bearing in mind that for models with replaceable batteries, the actual operating time will also depend on the quality of such batteries. For example, for flashlights for AA and AAA elements, battery life is most often given when using high-quality alkaline batteries; if instead of them inexpensive saline ones are used, the operating time may be several times shorter.
In general, when choosing a flashlight according to the maximum operating time, it does not always make sense to focus on “long-playing” models: they often have either low power or impressive weight / dimensions, and the price can significantly “bite”. Flashlights with a long battery life will be useful first of all to those who have to s...tay “away from civilization” for a long time: extreme tourists, rescuers, military, etc. And for most everyday tasks in a modern city, and even for trips to nature for several days, up to 10 hours is enough.
