# Avg lux in sunlight?



## Phaserburn (Oct 26, 2004)

What is an average lux reading in direct sunlight on a clear day?  Anyone know? I've seen many references to the color temp of sunlight, but not lux strength.


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## MoonRise (Oct 26, 2004)

Clear sky luminance is about 5.16 cd/in2 (8 kcd/m2) with a color temp of 6000K. That is equivalent to 2332 lumens/ft2, or 25,101 lumens/m2 which is 25,101 lux. (lux is lumen/meter2).

Shifting to photgraphy knowledge, since there are about 2-3 f/stops (each f/stop is a doubling of light) difference between direct sun and clear sky lighting, there would be about 100,000 to 200,000 lux.

The sun puts out a LOT of light. Also some heat. /ubbthreads/images/graemlins/smile.gif


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## Phaserburn (Oct 29, 2004)

Found this, for your amusement:

Outdoors Conditional Illumination 

(ftcd) (lux) 
Sunlight 10,000 107,527 
Full Daylight 1,000 10,752
Overcast Day 100 1,075
Very Dark Day 10 107
Twilight 1 10 
Deep Twilight .1 1.08 
Full Moon .01 .108 
Quarter Moon .001 .0108 
Starlight .0001 .0011 
Overcast Night .00001 .0001


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## thesurefire (Nov 3, 2004)

[ QUOTE ]
*MoonRise said:*
Clear sky luminance is about 5.16 cd/in2 (8 kcd/m2) with a color temp of 6000K. That is equivalent to 2332 lumens/ft2, or 25,101 lumens/m2 which is 25,101 lux. (lux is lumen/meter2).

Shifting to photgraphy knowledge, since there are about 2-3 f/stops (each f/stop is a doubling of light) difference between direct sun and clear sky lighting, there would be about 100,000 to 200,000 lux.

The sun puts out a LOT of light. Also some heat. /ubbthreads/images/graemlins/smile.gif 

[/ QUOTE ]


Does that mean that looking at the sun and looking at a 25,000 lux incan are about the same?


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## evan9162 (Nov 4, 2004)

Nope, it means that looking directly at the sun would be equivalent to looking at a 100K-200K lux light.


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