See related links below
Look under heading Explaination.
AnswerYou are mixing apples and Oranges! A lux is a special name given to a lumen per square metre. The former is a measure of luminous flux, or the rate at which visible light energy is emitted from a source, while a lux is a measure of the illuminance or luminous flux per unit area. Two different quantities!
Incandescent bulbs give about 10 lumens of light per watt of electric power Halogens give about 13 lumens per watt CFLs give about 50 lumens per watt So it depends on the type of bulb.
13000 MCD (millicandela) is a unit of luminous intensity, not luminous flux like lumens. The relationship between lux and lumens depends on the beam angle of the light source. You would need to know the specific beam angle of the light to convert MCD to lumens.
Lumens is the total amount of light a light source (a light bulb, for instance) throws in all directions. Lux (lumens per square meter) can measure how intense light from that light source is when looking toward it from a certain distance. Lux depends greatly on how far away you are from a light source. At any given instant, light is thrown from the source in a perfect sphere.If you are trying to calculate how many lumens your light bulb shines and you have a light meter that gives you lux, point your meter at the light, then take your lux multiply by 12.57 (pi times 4). Then, multiply this by the distance of your light meter from the light bulb (in meters) squared. That will give you the lumens of the light bulb. In equation form, where lm is lumens, r is your distance from the light source, and pi is (come on) about 3.14, lux=lm/(pi*4*(r^2)), or lm=lux*pi*4*(r^2). The (pi*4*(r^2)) part is used to calculate the surface area of a sphere around the light source.Note: this calculation does not account for reflected light, and will only work on an exposed light bulb. Lights housed in a reflective cone (like in a flashlight) are designed to project light in one direction and (within the spot where light is projected) will have a lux much higher at any given distance than if the light bulb wasn't housed in a cone.
The illuminance of direct sunlight is approximately 100,000 lux, but normal daylight, which is filtered through a cloudy sky, is between 5,000 and 10,000 lux, while moonlight can be as little as 0.25 lux. About 1000 Lumen is equal to direct bright daylight .
They really aren't equal because they measure two different things. However, they are related to each other.The Candela is the measure of the luminous intensity of a light source. A higher Candela number means a brighter light. Lux is a measurement of light density and means lumens per square meter. Again, a greater number of lux means that the surface being illuminated by the light is is receiving more light per square meter.The formula for calculating the conversion of candelas to lux is E = I/(D*D) where E is the Illuminance of the the surface in lumens per square meter (lux), I is the Intensity of the the light source in Candelas and of course (D*D) is the square of the distance from the light source in meters.Therefore 1 Candela will illuminate a surface with 1 Lux only at one meter from a light source. At different distances it will illuminate to different densities of light.For example: Solving for E, that same one candela light source would only read 1/4 lux at two meters [ 1/(2*2)] and 1/16 lux at four meters [1/(4*4)].If you know the lux at a given distance in meters from the light source you can solve for I and it will give you the intensity of the light in Candelas. From that you can calculate the intensity of the light.For example: Solving for I, multiply the lux times the square of the distance in meters and you will have the intensity of the light source in Candelas.So a reading of 8 lux at a distance of 3 meters would mean that the light source has an intensity of 8*3*3 or 72 candelas.
Lumens measure the total amount of light emitted by a source, candela measures the intensity of light in a specific direction, and lux measures the amount of light that falls on a surface. Lumens indicate overall brightness, candela measures brightness in a specific direction, and lux measures brightness on a surface.
The brightness of a light is determined by its intensity, which is the amount of light energy emitted per unit of time. This intensity is measured in units such as lumens or lux. The higher the intensity of a light source, the brighter it appears to the human eye.
Incandescent bulbs give about 10 lumens of light per watt of electric power Halogens give about 13 lumens per watt CFLs give about 50 lumens per watt So it depends on the type of bulb.
Candela measures the intensity of light emitted in a specific direction, lumens measure the total amount of light emitted by a source, and lux measures the amount of light that falls on a surface. Candela is used for directional light sources like flashlights, lumens for overall brightness of a light source, and lux for the brightness of light on a surface.
You can use a light meter to measure the brightness of a light bulb. This device measures the illuminance or luminance level produced by the light bulb and gives you a numerical value for its brightness in units such as lux or foot-candles.
Light intensity is measured in LUX, which is defined as LUMENS/square meter. Lumens derives from the base unit CANDELA.
13000 MCD (millicandela) is a unit of luminous intensity, not luminous flux like lumens. The relationship between lux and lumens depends on the beam angle of the light source. You would need to know the specific beam angle of the light to convert MCD to lumens.
To convert lux to watts, you need to know the luminous efficacy of the light source in lumens per watt. Then, you can use the formula: Power (watts) Illuminance (lux) x Area (square meters) x Luminous Efficacy (lumens per watt). This calculation will help you determine the power of light emitted by a source.
The luminous output of a 400-watt metal halide lamp typically ranges from about 30,000 to 40,000 lumens, depending on the specific design and efficiency of the bulb. To convert lumens to lux, you need to consider the area over which the light is distributed. For example, if the light is spread over an area of 10 square meters, the illuminance would be approximately 3,000 to 4,000 lux.
There's not a direct conversion, but both are based on the candela, a unit of luminous intensity. There is a nice explanation of the difference between lumens and lux at http://en.wikipedia.org/wiki/Lumen_(unit).Lumens is the total amount of light a light source (a light bulb, for instance) throws in all directions. Lux (lumens per square meter) can measure how intense light from that light source is when looking toward it from a certain distance. Lux depends greatly on how far away you are from a light source. At any given instant, light is thrown from the source in a perfect sphere.If you are trying to calculate how many lumens your light bulb shines and you have a light meter that gives you lux, point your meter at the light, then take your lux multiply by 12.57 (pi times 4). Then, multiply this by the distance of your light meter from the light bulb (in meters) squared. That will give you the lumens of the light bulb. In equation form, where lm is lumens, r is your distance from the light source, and pi is (come on) about 3.14, lux=lm/(pi*4*(r^2)), or lm=lux*pi*4*(r^2). The (pi*4*(r^2)) part is used to calculate the surface area of a sphere around the light source.Note: this calculation does not account for reflected light, and will only work on an exposed light bulb. Lights housed in a reflective cone (like in a flashlight) are designed to project light in one direction and (within the spot where light is projected) will have a lux much higher at any given distance than if the light bulb wasn't housed in a cone.AnswerA lux is a special name given to a lumen per square metre. To convert lux to lumens, you need to multiply the illuminance (light arriving) on a surface, in lux, by the area of that surface, in square metres.
The illuminance of direct sunlight is approximately 100,000 lux, but normal daylight, which is filtered through a cloudy sky, is between 5,000 and 10,000 lux, while moonlight can be as little as 0.25 lux. About 1000 Lumen is equal to direct bright daylight .
Light is measured in units called lux (luminous flux per unit area) or lumens (total amount of light emitted by a source). Lux is commonly used to measure the intensity of light falling on a surface, while lumens are used to measure the total output of light from a source.