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You need to go read Don K's lighting web pages. You can also go toI have an array of an unkown LED and a lightmeter that only reads
footcandles and is color and cosine corrected.
Is there a way to convert footcandles to mcd (roughly)?
LEDs are red, water clear and at ~6mA are quite bright.
Jeff
Hi,I have an array of an unkown LED and a lightmeter that only reads
footcandles and is color and cosine corrected.
Is there a way to convert footcandles to mcd (roughly)?
LEDs are red, water clear and at ~6mA are quite bright.
Jeff
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Jeff wrote:
I have an array of an unkown LED and a lightmeter that only reads
footcandles and is color and cosine corrected.
Is there a way to convert footcandles to mcd (roughly)?
LEDs are red, water clear and at ~6mA are quite bright.
Jeff
Hi,
0.0929 footcandles [fc] = 1 lux [lx] = 1 lumen per square meter
[lm/m^2]. On the other hand, 1 candela [cd] = 1 lumen/sterad [lm/sr].
So, in order to convert from lux to candela (or millicandela [mcd]) you
have to convert the illuminated area (measured in square meter) to the
corresponding solid angle (measured in sterad): to this end, divide the
illuminated area by the square of its distance from the light source.
Hope this helps,
Martin.
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Hi.
Thanks, thats what I needed, a description in english of
the math involved with these standards I am not used to
at all.
So we came to the conclusion last night after posting
the question that there are too many varriables to deal
with without a known reference to acheive an accurate
rough approximation within 200mcd or less.
(we = a few friends + a few beers)
I will order a few higher output LEDs for future
reference and maybe some other parts to make a
more accurate measurement tool.
Thanks to all.
Jeff
Given the above, mcd is 1,000 times the footcandles, multiplied by theI have an array of an unkown LED and a lightmeter that only reads
footcandles and is color and cosine corrected.
Is there a way to convert footcandles to mcd (roughly)?
LEDs are red, water clear and at ~6mA are quite bright.
Don and all thanks!In article <0o0mb.12634$Ec1.1119801@bgtnsc05-news.ops.worldnet.att.net>,
Jeff wrote:
I have an array of an unkown LED and a lightmeter that only reads
footcandles and is color and cosine corrected.
Is there a way to convert footcandles to mcd (roughly)?
LEDs are red, water clear and at ~6mA are quite bright.
Given the above, mcd is 1,000 times the footcandles, multiplied by the
square of the distance in feet between the LED and the lightmeter.
Give or take various meter errors including any in its color correction,
as well as matching human vision in determining visibility of different
wavelengths of red, blue and violet.
- Don Klipstein (don@misty.com, http://www.misty.com/~don/ledx.html)