What is the formula to work out beam distance

As per title. I'm struggling to find this on Google. Don't think I've missed anything obvious either. How the heck do you work out beam distance from candela????
Specifically how far in meters does 400kcd throw
I know that 422000cd is 1300 meters as per the acebeam k70. So I guess it'll be 1250ish meters but intrigued how it's worked out
Thanks

If you take the square root of the given cd, that will give you the distance in meters for 1 lux .
Multiply that number by 2, and you'll get the make believe throw distance to 0.25 lux.

So... working in the other direction.
If you have the throw distance to 0.25 lux.
Divide by 2, you'll have the distance to 1 lux.
Then square it, and you have the cd.

With the known cd, it is easier to compare one light to another, and whether it will throw far enough light for your particular needs. (LOL... but you knew that! )

Perfect..thanks

torchsarecool said:

Perfect..thanks

Click to expand...

I learned that from our friend TEEJ