300 lumens + 300 lumens = ??

Hi, this is probably stupid, but ...

If you have two lights at 300 lumens each and you point them both at the same subject, do you get 600 lumens of illumination or the abouts? My friend checked this out for me and he said that when he overlapped the beams of two lights, the overlapped section did not appear any brighter than the rest.

Sent from my iPad using Tapatalk

Find me on Twitter if you like @BazMattaz

Yes. This is for example how multi led lights work.

Yes, the lumens add, but the eye doesn't see 600 as looking twice as bright as 300. The brain is very accommodating when it comes to eyes and ears.

Practically, lumen measurement is taken on the front of the torch's lens.

Once it has traveled through water a short distance, you will be seeing substantially less than 300 lumens per side. To be honest, my experience of 300 lumen lights underwater is that I can't see much effect!

If you were to conduct the experiment in a dark room (in air), you would see a brighter area where you have the output of both torches overlapping.

Adam

Lumens is how much light there is; the brightness on an object depends on the distance to an object, and how much the beam is spread. A narrow beam, 200 lumen light is actually pretty bright on an object; a wide-beam 200 lumen light is pretty dim on an object...the lumens are spread out over a large area.

I guess if the question was whether would you see a difference when two 5,000 lumen lights overlap, the answer would be yes you would

Many thanks for your help people

Sent from my iPad using Tapatalk

Find me on Twitter if you like @Baz_Mattaz