I wish I could but I just cant. Congratulations to the lucky people who grab these. :bigsmile:
+1
i would be all over these if i wasnt busy destroying mine!
If the tint in real life looks anything like in the pics, it ought to be gorgeous. If I could spare the cash right now…the side switch upgrade doubles the appeal over the stock 3D light.
Gotta jump on the 3D! Heading over to PP now. >)
So, someone help me here with the calculations for throw. I see the thread I was using is gone, as well as a member.
Defiant 3D @2meters - 24,900 lux and @10meters - 2,800 lux
Defiant 3C @2meters - 76,900 lux and @10meters - 8,000 lux
EDIT: I think the meter might have been on x10, not on x100 so these numbers might make more sense?
Defiant 3D @2meters - 2490 lux and @10meters - 280 lux
Defiant 3C @2meters - 7690 lux and @10meters - 800 lux
How do I convert these numbers. The formula I had is gone.
Reading at 10m x 100 (10^2) for 1m equivalent
My apologies. I never got past basic math in school. I do not know what that symbol means and does the result equal throw in meters?
Take your LUX reading at M meters. To calculate the equivalent reading at one meter calculate:
LUX times M times M
For a sanity check compare the calculated 1 meter readings taken at different distances. They should be close. If they are not, then most likely the beam profile has not leveled out at the closer distances and you need to take the readings at a farther distance.
To calculate throw distance, take the calculated 1 meter LUX reading, multiply it by 4, and then take the square root of that number. That is the throw distance in meters (when the lux reading should be 0.25 lux).
Old-Lumens,
The ANSI FL-1 standard dictates that throw is the maximum distance a light is supposed to paint 0.25 lux on a target.
The 3D’s reading you took at 10m is equivalent to 28kCd, good for 335m of throw to 0.25 lux.
The 3C’s reading you took at 10m is equivalent to 80kCd, which is good for 566m of throw to 0.25 lux.
As texaspyro pointed out, you’ll find that you get a more representative reading further away, especially when larger-reflectored lights such as these come into play.
Thank you.
So if I do the 1M reading and them keep going farther out, at some point I will find a peak, where the beam is collimated?
Thank you
Depending upon the beam profile, it might not be a peak. The calculated 1 meter readings could be increasing or decreasing as you move farther out, but at some distance they should settle down to a reasonably constant value.
Also, you want to take the reading at the brightest point of the beam. That may not always be apparent to the naked eye. Move your meter around and hunt out the hotest spot.
I could not read the meter and aim the light at the same time, so I enlisted my wife. Picture her with her back to me and the meter sensor hanging over her shoulder, on her back, while she reads the meter itself, as I aim the lights at her back. I did move the beams around and she recorded the highest reading from each.
She puts up with a lot!
Yes, especially in the case of these two lights with honkin’ big reflectors. You’d find a measuring distance that gives readings close to the maximum throw potential. Any further than that yields minimal returns.
We can use the throw equation,
ANSI Throw = SquareRoot[(lux reading*distance from lux meter*distance from lux meter)÷(0.25 lux)]
and the readings you took to demonstrate this idea.
For the 3D’s reading you took at 2m:
Throw = SquareRoot[(2490)(2)(2)÷(0.25)] = 200m
Compare this to the 335m of throw obtained by the 10m reading. The 10m reading more closely represents the true throw of which the light is capable.
I should have been more clear. 10^2 is ten squared or 10 times 10. As everyone else has said, simply multiply your meter eading by the distance squared to get equivalent 1m reading. The throw formula is a post or two above this.
does your lux meter not have a peak function?
No, it does not. It’s the one I am sending back, because it’s the wrong one.
I have that same meter. What i do is measure from 3 meters on the 20,000/x10 setting what ever that number is I multiply that number x 3 x 3. For example the jacob a60 does around 800.
So that would be 800 x 3 x 3 = 7,200 then add the zero for the x10 setting which give 72,000 or 72k
Hope this what you are looking for dont know though. Heck hopefully i am doing it correct. I just know that that is about the numbers some people are getting out of there stock lights.
I think your distances or readings are in error.
Because your second set of readings (from 10m) is 5 times as far from the source as your first set (from 2m), the lux readings at 10M should be approximately 1/25th of the readings at 2m, with some leeway for measurement error and optics. This is the “one over r squared” rule (1 over 5 squared = 1 over 5 times 5 = 1/25).
Your readings are more like 1/9th for two different lights with totally different beams which implies a consistent error. Either the two distances were actually 3 times as far from the lights or there’s some issue with the readings. I’ve done this extensively with all kinds of lights at varying distances and see nothing about your lights, either from the beam shots or the optics, that would warrant such a huge discrepancy.