Among flashlights specifications, you often encounter the terms Lux, Lumen and Candela. What do they mean and how they relate?
Lumen, Candela and Lux are every 3 units for measuring light. However, one can not directly compare.
Lux is a measure of the intensity of the light falling at a specific location. For example, on a wall or on the floor of an office. Lux 1 is about the brightness of a candle 1 meter away.
You can add the Lux, so if one candle product 1 Lux at 1 meter distance, then 2 will light candles to Lux 2 a meter away.
If the distance from a light source is doubled, the number of lux falling on a surface is reduced by 4. Thus, an average candle product approx. 0.25 lux at 2 meters distance. This is because the surface to be illuminated is 4x larger.
Lux is not a unit that can be used to measure the light intensity of a light source such as a flashlight. However, this is a unit that is the basis of Lumen and Candela units used in flashlights specifications.
Candela / Candle Power
Candela, also called Candle Power, Lux is the amount of a light source product to 1 meter distance, at the brightest spot of the beam. This is a measure which was previously widely used to specify the light intensity flashlights. The Candela tells you about the intensity of light, but not on the total amount of light. After all with a reflector or lens, you can get more light intensity (and therefore more Lux), without necessarily using a more powerful lamp.
Lumen is a measure of the total amount of light from a lamp. With Lumen unit of measurement, the beam does not matter. Two flashlights that offer the same number of lumens do not have to be too bright or have the same scope.
The Lumen is a measure that is now widely used in flashlights specifications.However, the number of lumens is silent on the scope of a lamp. You must then take into account at least the shape of the beam.
Fortunately nowadays many manufacturers also give, besides the number of lumens, the distance a flashlight can achieve and, in addition, we conducted our own measures. Read more: Ranking of the most powerful flashlights.