Thanks jhalb. I would like to make a new setup. I have been using a pretty rough light box for years. The other day I made one of those lumen tubes just for fun, but am not all that impressed with it. I was thinking for the new sphere I will probly cut the hole for the size of a maglite head since I work with them a lot. I will keep the lumen tube for measuring larger lights as it was made from 4” pipe.
I have another question for the pros… What method are you guys using to derive your multiplier?
I have always done it like this.
1. Take know source ( in my case 875 lumen maglite measured by another member).
2. Divide lumen output by lux reading.
Example 875 lumen light produces 2550 lux. So 875 divided by 2550= 0.343
So from hence forth all measurements from other lights are multiplied by .343
However just now reading posts by others I see that Match appears to be doing the opposite.
A quote from his post.
but the most accurate one I tried was to simply take a light of known value, test it to get the lux reading, and then divide that reading by it’s alleged lumen rating.
Then here I looked and found yet an even more obscure method. Something about measuring the hole??
How are you doing it?