Old-Lumens —-a very well respected member , posted this in 2013 here on the BLF in reference to integrating spheres for measuring lumens.
“There’s a reason why an IS is minimum of $10,000. What we do has nothing to do with true readings or even ANSI lumens output. All of the home made IS spheres are subjective and only meant for something for your reference, but they would not be true lumens, nor would they be necessarily repeatable with a whole span of different lights.
In other words, any readings from a home made sphere, or worse, (light box or PVC), are just speculative and cannot be considered true lumens readings. I think too many people take some of the results they see as gospel and they can be totally way off from true lumens readings.”
So why not take some general measurement comparisons of various lights you own and share the results. As stated in the quote above, it’s not going to be 100 % accurate but it will provide some very useful information.
A meter reading from the hottest /intense part of that beam shot on the wall
as well as a measure of the diameter of that same hotspot,
Record the distance from the wall
*****Now you have info to calculate a general idea of multiple aspects at one time.
1- Lumens out the front
2- Candela ( throw)
3-Beam angle
(How wide that hotspot is going to be at any point of distance forward down line, do the Geometry or equation of your choice)
Share your findings here,
I would not like to think that the good old innovation, curiosity ,and helpfull
Qualities the BLF is known for are fading, or becoming more like that other….
Most of the time, due to variance in environment settings, photos just don’t
Seem be the best way on their own, and beam angle data is usually missing from reviews as well.
The old-Lumens comment was sourced from this thread Measuring Lumens, how do you do it?