When you choose tactical lights, you often see the values of luminous flux (lm) and illuminance (lx). How do we use these values to judge whether the tactical lights are on or off? I will share it with you today.


First, we need to understand the meaning of these values:
Luminous flux refers to the amount of light emitted by a light source per unit time, called the luminous flux of a light source, in lumens (lm). Illuminance refers to the amount of light flux received by the visible light per unit area, in lux (lx).


In simple terms, luminous flux refers to how much light a light source emits, and the illuminance is how much light is on the illuminated object. For example: 1250lm ordinary incandescent lamp and 200lm ordinary tactical lamp, in the same environment, we will feel the brightness of the tactical lamp is higher, why?


The reason is the illuminance. When the illuminance per unit area is larger in the same environment, the brightness will be higher. The brightness of tactical lights is higher than incandescent lamps because the illuminance of tactical lights per unit area is greater than that of incandescent lamps. From the above case, we conclude that the size of the luminous flux (lm) is independent of the brightness, not the brighter the luminous flux, but the illuminance per unit area.Then the question comes. When choosing a tactical light, is the greater the luminous flux, the better? Actually not. The luminous flux of conventional tactical lighting should be higher than 60 lm, but not the higher the luminous flux (lm), the better. When the tactical light use environment is a small space in a city street and a building, the lighting light is likely to be reflected back at a close wall or mirror surface, and the excessive brightness will greatly interfere with its visual function. Not only is it not conducive to search, but it is extremely easy to have a negative impact on observation and judgment, and increase the risk of exposure.

It can be seen that in close combat, we should choose a tactical light with a relatively high luminous flux and a high illumination divergence angle (the divergence angle refers to the angle of the beam illumination). This kind of light covers a wider area, and the illumination is low, it will not interfere with the shooter's line of sight. The commonly used is the American CREE R5 lamp bead.

When the tactical light is used in a long distance, such as an open field, in order to observe the distant target and understand the surrounding environment, we need tactical lights with sufficient brightness to ensure that our sight is clear. At this time, we should choose a tactical lamp with large illumination and small divergence angle. Because the illumination on the unit area is larger in the same environment, the brightness will be higher, thus ensuring the clear vision of the shooter. The commonly used CREE is American. Q5 lamp beads.



So, what is the difference between the R5 and Q5 lamp beads mentioned above?

Through the comparison of the pictures, we found that the R5 lamp beads have low illumination, large divergence angle and good flooding, which is suitable for close-up combat of pistols. Q5 lamp beads have high illumination, small divergence angle and good concentration. They are more suitable for long-distance illumination on rifles. Judging from this, when selecting tactical lights, it is necessary to make choices based on the specific use environment, combined with the characteristics of tactical light flux and illumination. The above is a brief introduction of luminous flux and illuminance. The next issue is to explain how to judge the brightness of laser products based on numerical values. Stay tuned!