> I was shopping for a flashlight recently, and naturally
> noticed a trade-off between size/compactness and brightness.
> The devices range up to 500 Lumens.
> Human perception is logarithmic. So I wonder, at what
> point, measured in Lumens, does apparent brightness
> level off? For instance, imagine you're in a dark place,
> and you want to blind an adversary. How many Lumens required?
Lumens are like watts---they measure the total amount of visible light.
A good 100W incandescent bulb circa 2012 put out 1690 lumens. That's a
whole lot for a flashlight.
For a narrow-angle applications, you care more about lux (lumens/sq
metre). 1000 lux is a nice number for reading a book, but 5000 is better
for an old guy doing close work. ;)
For incapacitating somebody, you're much better off with an 8-D-cell
Maglite, know wha' I mean?
Dr Philip C D Hobbs
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510