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TECHNICAL INFORMATION
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TEC
Candela is a term that refers to the amount of visible light at any one point, within a specific light pattern. Candela
values measure intensity of light at a specific location, and this number, just as lumen values, can be used to mislead.
For instance, you could have two different flashlights (Flashlights A and B) that both claim to be 18,000 candela. This
gives us a general idea of the capabilities of the flashlight, but leaves much to be questioned about the performance.
Since candela is the measure of light intensity—
not
total light output. Remember, lumen equals total light. Both of
these flashlights can claim that they output 18,000 candela even though they are clearly not performing at the same
level. Flashlight A illuminates half of our subject, as does Flashlight B. However, Flashlight A is covering a much wider
area of our subject at the same candela value as Flashlight B, which means we can assume that Flashlight A has a
higher lumen value.
Lumen values cannot accurately be converted into candela values (and vice-versa), because they are measures of
completely different elements.
Another way to compare candela and lumen values, wouldbe to think of a pressure-washer and a fire hose. Let’s assume
our fire hose has a 2-inch diameter barrel and our pressure-washer nozzle head is 1/16
th
inch. Now lets say that both
our fire hose and pressure-washer are pressurized to 2700psi, or in other words the water will be flowing out of each
hose at the same intensity. Both hoses are rated at 2700psi, yet, the fire hose displaces much more water overall.
Lumen would be the equivalent of
the total amount of water coming out
of the hoses and candela would be
equivalent to the amount of pressure
from where the water is flowing.
A lamp is successful only when
it illuminates what it is supposed
to be illuminating. A ball with ten,
one-hundred lumen diodes placed all around its surface, would
technically be rated at 1000 lumens, but it would make a very poor
spot light.
The Candela:
A Measurement In Flux
18,000 Candela
18,000 Candela
A
B
2700
psi
2700
psi
Identical
Intensity
Different
OUTPUT