As outdoor flashlight fans, we need to know some of these commonly used LED strong light flashlight terms in order to avoid being fooled in the purchase.
1. Luminous flux. The total brightness emitted by the illuminant. Only when the unit lumen is LM, can the professional integrating sphere measure accurately.
2. Light intensity. The total light flux per unit area. Unit lux, the illuminometer can measure accurately.
3. Light efficiency. Luminous efficiency, luminous flux of the emitter at 1W power. The unit lumen is LMW per watt.
4. VF value. In short, it is the working voltage of LED under the current.
5. Focus. In pursuit of the projection distance of the flashlight, the smaller the luminous angle of the LED and the larger the size of the light cup, the better the focusing performance.
6. Floodlight: floodlight is just the opposite of spotlight, pursuing the irradiation area. Need large angle led and small light cup.
To see whether the flashlight is on or not, ordinary users only need to check the brightness of the central spot of the flashlight. However, if you are a flashlight enthusiast, you can't judge the actual brightness of the flashlight only by the brightness of the central spot. This is because the brightness of the central spot can only reflect the light intensity of the flashlight, but not the overall luminous flux of the flashlight.
It's not that the higher the light intensity, the higher the luminous flux. Only the smaller the luminous angle of the LED, the larger the size of the light cup, then the better the spotlight, light intensity is certainly high. So it is possible that the central spot brightness of a flashlight with a large aperture light cup is brighter than that of a flashlight with a small aperture light cup. But if you use it at night, you can find a big difference. The illumination area and brightness of the flashlight with small aperture light cup are better than those with large aperture light cup.