This is because lumens measure the total amount of visible light from a light source.
CANDELA LUMEN CALCULATOR FULL
Obscuring half the bulb (making it a hemisphere instead of a full sphere), a 1 cd bulb will emit only 6.28 lm. For a bulb emitting 1 cd, that bulb would also have a luminous intensity of 12.57 lm.
To show the difference between lumens and candela, let’s go back to the example previously used for candela with the partially obscured light bulb. To put it simply, the lumen rating is how much total visible light is produced by a light source. The lumen (lm) is a measurement of luminous flux, or the total amount of visible light. Lumens are now the most common measurement for a light bulb. To get the luminous intensity in candela: Enter Luminous intensity in candela: Candela to lumens calculatorĮnter the luminous flux in lumens, apex angle in degrees and press the Calculate button
CANDELA LUMEN CALCULATOR HOW TO
By your logic, everything that gets hit by sunlight would also look darker the further away it is.Candela (cd) to lumens (lm) calculator and how to calculate. It will just be smaller when further away. Assuming no loss in atmosphere, 0.25 lux will look just as bright in front of you as it will 100m away. If you shine the light at a wall 100m away then the light will be bright enough for someone standing next to the wall to see but for you to see the wall, the light has to bounce back another 100m to your eyes.” “This means that a light with 100m ANSI throw won’t allow you to see 100m away clearly. If I wanted to calculate the distance at which the brightness will be 2 lux for example, I’d divide the candela by 2 instead before taking the square root. So while “times 4” isn’t wrong mathematically, it certainly doesn’t help understanding that actually it should be “divided by 0.25” since that’s the brightness value selected. Throw (in m) is calculated from intensity (in cd) by assuming a brightness of 0.25 lux. Your use of “times 4” and “divided by 4” bothers me. Here’s some examples from candela to meters:Īnd some examples from meters to candela: Dividing by 0.25 is the same as multiplying by 4. Watch out for the “k” in “kcd”, which means 1000.Īs Streamtronics pointed out in the comments, technically you divide the candela by 0.25 (as throw is measured at 0.25 lux). Or square the throw in meters then divide by 4 to get the candela. Multiply the candela by 4, then square root it to get the throw in meters. You can convert between throw (m) and candela (cd) quite easily. Converting between ANSI throw and candela The 0.25 lux when measuring throw is about the same brightness as a full moon.Ġ.25 lux from the moon is enough to hike fairly easily. Mega throwers can throw over 1000m (1km or 2/3 of a mile). More “throwy” lights are useful outdoors, where 500m or more throw can come in handy for seeing things far away. Mid range lights with 200m to 400m are useful indoors and out. If you have a light with lots of throw indoors then you’ll only be able to see one small area at a time. With a headlamp or flashlight for use inside, throw over 300m isn’t especially useful unless you want to point at things. When buying a flashlight you generally want a certain amount of lumens (total light) and throw (for seeing things at a distance). Throw (m) is an ANSI measurement that relates to the distance that a light generates 0.25 lux.At twice the distance, the area the light hits is 4 times the size, so you’d need a 4cd light to produce 1 lux at 2 meters. Candela (cd) is how intense a light us at 1 meter.Going further away from a light source makes it less intense and reduces the lux, so lux measurements by themselves aren’t very useful for comparing lights. If you have 100lm, you can make them more intense by pointing them all in the same direction with reflectors or lenses. You can think of Lux as how intense or concentrated the lumens are. Lux is how much light there is in a square meter.
More lumens means a brighter light and generally takes more power to produce. Lumens (lm) is how much light there is in total.These measurements are both about how bright a flashlight hotspot is, rather than the total brightness, which is measured in lumens. Or square the throw in meters then divide by 4 to get the candela.įlashlight specs sometimes mention their throw in meters (m) or their intensity in candela (cd or kcd for thousand candela). Tl dr: Multiply the candela by 4, then square root it to get the throw in meters.
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