lumen power meter

any ideas on a good or what type of lumen meter will work for checking flashlights? I notice a lot of units designed for photography but not sure id they will work

I like using photography light meters to measure lumens. If you calibrate to, and solve for shutter speed, you have your lumens conversion built right in. The 1/3 photography stops can be kinda wide increments but in practice, many meters register midpoints and so I feel are +/- 10% accurate. If you have EV numbers, there's a formula to convert them to lumens with 1/10-1/100 stop theoretical accuracy.

I've used DSLRs and free smartphone apps with good results - spend 5$ for a few plumbing elbows and you have fine lightbox too .

I'm sure somebody will come in shortly with full and accurate information. In the meantime I will share what I have been doing. I have used camera light meters and I figured it could give somewhat relative ratings. For instance one full stop is twice or half the light etc. Later I got this meter that supposedly measures lux and footcandles.

http://www.amazon.com/dp/B005A0ETXY/?tag=cpf0b6-20

Now how accurate can it be for $30? I really just used it to give me relative results. I figue if it is wrong on one it will be relatively as wrong on the next light. There probably is a way to convert to lumens on this too, but I don't have that at hand. The best way will be to check out selfbuilt's reviews and he has a detailed accurate way of doing it in a sphere.

Lumens is a measure of total light output, not just the brightness of the center of the beam. You need an integrating sphere to measure that.

Found this link on building an integrating sphere.

http://www.candlepowerforums.com/vb/showthread.php?200334-Building-an-Integrating-Sphere/page5