Domes on strobes and video lights - benefit or hype?

I was recently running a boat and one of my guests had a set of Inon Z330. He told me he had issues controlling the power of the strobes and even at low setting in close up work they were still too strong.

This reminded me of an experiment I did a few years back and never decided to publish, perhaps the time has come.

In essence I believe there is no value in having curved shaped video lights or strobes for two reasons

1. The light source is essentially on the glass is not a far distance light ray that is going through water

2. There is an obvious effect of scattering around the light itself that actually expands the beam. This is very noticeable with strobes where you literally see a cloud around the strobes that is is due to light particles colliding with water

My conclusion was at the time that light at the strobes actually expands compared to use in air due to rayleigh scattering for what concerns blue light while red tones are absorbed by water and therefore a dome shaped strobe or light front is not necessary. Also important to make a distinction between angle of coverage and diffusion of light

So my take is that curved surfaces increase diffusion but don't really do much to increase actual coverage angle, at short distance the diffusion effect may be too strong and the light source be too invasive and need a device to reduce the beam

I did not want to publish the video evidence at the time (you can do yourself in a sink) because those products had just been released and did not want to create a ****storm however I personally have no interest in curved shaped lights they are not practical and make things more complicated than required and I will stick with flat lights for the foreseeable future...

I figure you are correct that the beam angle wouldnt change (much) if the light source is at the same given depth within the opaque part of the light housing, but I always figured having a domed front for a light would allow for a more foward seating of the source which would expand the angle by simply uncovering more of the beam. 

I figure you are correct that the beam angle wouldnt change (much) if the light source is at the same given depth within the opaque part of the light housing, but I always figured having a domed front for a light would allow for a more foward seating of the source which would expand the angle by simply uncovering more of the beam. 

I thought it was similar to using a dome port vs. a flat port in helping to get a wider spread of the light by avoiding the focusing effects of refraction.

It sounds like your guest was adjusting the power knob but had the strobe in full power mode.

6 minutes ago, rwb500 said:

I thought it was similar to using a dome port vs. a flat port in helping to get a wider spread of the light by avoiding the focusing effects of refraction.

It sounds like your guest was adjusting the power knob but had the strobe in full power mode.

It does not because there is not a light beam travelling at distance

Put a video light in a sink and you will see that the beam actually expands when there is water due to scattering around the light

As the light emitting source is close to the surface the effect of refractive index appears to be less important than the scattering

When you have a port instead the light travels inside the housing where there is a considerable more length of air so it seems the conclusion that is the same thing does not hold

All the dome surface does is to increase diffusion but does not make the light rays go any deeper

16 hours ago, Interceptor121 said:

It does not because there is not a light beam travelling at distance

Put a video light in a sink and you will see that the beam actually expands when there is water due to scattering around the light

As the light emitting source is close to the surface the effect of refractive index appears to be less important than the scattering

When you have a port instead the light travels inside the housing where there is a considerable more length of air so it seems the conclusion that is the same thing does not hold

All the dome surface does is to increase diffusion but does not make the light rays go any deeper

I'm not sure what a lot of this means, sorry.  But I do believe the dome shape increases coverage.  And while there is some random scattering of light due to debris in the water, I believe it is relatively minor in water that is clear enough for wide angle photography.

4 hours ago, rwb500 said:

 
I'm not sure what a lot of this means, sorry.  But I do believe the dome shape increases coverage.  And while there is some random scattering of light due to debris in the water, I believe it is relatively minor in water that is clear enough for wide angle photography.

Scattering happens also in clear water this is the reason why water looks blue
Light is made of particles and so is water. Debris creates backscatter not scattering
As I said put a video light in an empty sink take a photo then fill the sink and see what you get

I think Inon explains it fairly on their Z330 the benefit of a dome shape is to be more effective at diffusing and therefore use a bit less power. However in terms of angle of coverage a traditional strobe with a standard diffuser achieves the same result

So the dome shape diffuser may give an edge when it comes to power to angle of coverage compared to a traditional strobe with a standard plastic diffuser.

My point is that if you have a strobe with a dome shape that is less powerful than a flat one at the end you put a diffuser on the flat one and you are back to the same place with less money in addition you can always take the diffuser off in those cases you don't need it instead of having to put a device to restrict the beam


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Often wondered about this - good topic....

Hans

"Light is made of particles and so is water" , unless it is when light is made of waves
Bill

"Light is made of particles and so is water" , unless it is when light is made of waves[emoji5]

Bill

Light is made of photons and can be analysed as waves or particles

Scattering and other phenomena are better explained using particles

Likewise camera sensors are modelled through photon conversion into electrons

Some elementary optics approximates light as geometric rays especially when looking at lenses but then you can’t explain a range of other phenomena with that model

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I understand (sort of) both the Maxwell Equations from the wave side and the photoelectric effect from the particle size (several classes in QM) and was mostly just teasing. My impression of Raleigh scattering though is that it is the oscillating electric field (waviness) of the light that leads to scattering. Same for some types of inelastic scattering.

Cheers

BVA
 

I understand (sort of) both the Maxwell Equations from the wave side and the photoelectric effect from the particle size (several classes in QM) and was mostly just teasing. My impression of Raleigh scattering though is that it is the oscillating electric field (waviness) of the light that leads to scattering. Same for some types of inelastic scattering.
Cheers
BVA
 

I have shot the Iron Z330 and the Z240 with the dome diffuser and flat and mostly can't see a difference. Maybe for some specific shot it might matter.

Bill

I have shot the Iron Z330 and the Z240 with the dome diffuser and flat and mostly can't see a difference. Maybe for some specific shot it might matter.
Bill