How to calculate throw from candela?

LED Flashlights – General Info
1

I am sure that I did saw the formula somewhere in some topic, but there is so much content here... Should have wrote it down...

So, candels to meters!

2

sqroot of candela *2

EDIT: that’s to moonlight,

to 1 lux is just sqroot of candela, and to 2 lux is *0.5

EDIT2: this table is relevant. source

3

Thanks

4

Please refer to here: http://flashlightwiki.com/Light_Output_Measurements, para on throw. The FL-1 standard is based on 1/4 lux, which is moonlight.

100 kcd is 632 meters using this equation: SQRT(100000/0.25).

5

I think it’s easier to just square root the candela and multiply it by two, but that equation is still correct. Just another way of doing it :smiley:

6

Ooops, yes: SQRT(4) = 2, so the math works!

x/0.25 = x * 4, --> SQRT(x * 4) = SQRT(x) * SQRT(4), so --> SQRT(x) * 2

Ex: SQRT(100,000) = 316.228, 316.228 * 2 = 632.456

7

Yup :slight_smile: