Measure at 10 meters for throwers. Set it to lux, and measure…
I was thinking to use a box, cover it inside with aluminum foil to make a ulbricht sphere / “ceiling bounce” device…
shouldn’t I get consistent values from a thing like that?
- I want to compare my lights together
(like: my DD-Hd2010 puts double the light than my stock C8)
same with throw…
at (some) distance, A has 4 times the lux than B
if I get numbers which are comparable with you guys here in the forum - that would be great
Normally for stock lights we should get the same numbers with some lttle deviation.
Regarding lux the bigger the diameter of the head of the light the further the distance should get more precise measurements. For small light 3,18 m should be enough in my opinion allways assuming light are focused @ infinity.
For total lumens in bounce there is not an fixed distance, just choose one that is easy for you and allways use that distance in other measuremen(an fixed value for both your light meter and your flashlight). U have to own an light from an trusty brand with an known lumen value first. In this way you will get the koeficient of your setup and after that you can use that coeficient to find lumens in other flashlight. Hope i dont make it a mess for you.
Celling bounce should be ok as well, make sure you put the lights at same position, and aim for same spot. Even if you don’t it will still be very accurate.
Compared to one other, similar class lux meters, HS1010A showing like 5-10% less lux, some users said it was showing a bit low, i guess its true because it show less in my case as well.
thanks!
If you are measuring lux I’d advise getting a tripod or similar for the light so it points at right angle to the sensor, so you can get repeatable results first with the same light.
Then measure at intervals, generally 1m, 3m, 5m (depending on the light size/power and how much space you have). You can take the candela from each distance and compare (numbers will be different but you can observe a trend):
The first minute is most crucial in terms of peak output so use a stopwatch and log it. 30 seconds seems fair from my testing.
For example, the first minute of an Olight ST-25 running on eneloops spans some 100 lux:
Of course there is some variation between different users measurements depending on this factor alone (not to mention bin and calibration variations).
Is that a buoy? Looks cool!
how do you guys measure the lumens via ceiling bounce?
Thanks Cloe, agree on your method!
I feel like I’m an idiot or something…. can someone help me understand what I’m reading here and how to convert it to intensity. This is what I got when I measure a Nitecore MH12 @ 2 meters:
2190 x 4 = 8760cd