Are UW video lights additive

[Craig66]

If I use two 500 lumen lights. Do I have 1000 lumens or do I have 500 lumens but with a wider field of light?

Thanks

Craig

 

[EastEndDiver]

If I remember my college physics correctly Light in not cumulative,you have two 500 lumen lights with a wider beam.

 

[Ed Palma]

It would be somewhat cumulative... after all, that's the basis for multi-LED lights.

 

[ronscuba]

It would be somewhat cumulative... after all, that's the basis for multi-LED lights.

Lumen ratings on lights can be misleading. A reflector is used to create the light beam. It could be narrow or wide depending on what the mfr is trying to emphasize. A wide beam covers more area, but will be less intense and look less bright.

There is some lumen loss from the reflector. Most manufacturers list the lumen rating of the element and don't account for the loss due to the reflector. Not all reflectors are the same. Some lose more light than others.

A mfr will list their light as 4000 lumen because it consists of 10 LED elements with each element rated at 400 lumen. However, the total light output in actual UW use will not be 4000 lumen. You have the loss from the reflector and the loss because light is not 100% additive. The physics guys can answer what the % is, but I know when I use my two 1500 lumen "rated" LED lights, turning on the 2nd light does not make the scene look twice as bright.

Unfortunately, there is no industry requirement to test, measure and document the lumen output of the finished product.

 

[DazedAndConfuzed]

photons could act as a waveform and destructively cancel each other out if the dispersed beam is allowed to re-emerge together again.

 

[ronscuba]

photons could act as a waveform and destructively cancel each other out if the dispersed beam is allowed to re-emerge together again.

I don't think I ever learned in school what this means and even if I did, I am too old to remember. Can you explain ?

 

[drbill]

I wasn't very good in physics, but there is one side of the question I can answer... a second video light will indeed be additive... in terms of cost!

 

[gracet]

Assuming two lights are shining their circles together at the same spot, (fully overlapped and at the same distance) the light energy of two seperate lit spots (at the wall) should be fully additive when the spots are fully overlapped. The percieved human brightness might not be twice. The camera perceived brightness should be twice. We are talking about the brightness of one spot from one light, compared to two fully overlapped spots from two lights at the same distance. Losses from the light bulb to the wall are very real, but a comparison test between one and two lights could be made and judged at the wall.