Use case for diffusors on small LED video lights

[DirkPeh]

I just got the small Ace Amaran 25x video-lights. I bought them as a toy and they are a bit more, really impressed.

The set came with a small magnetic grid and one of these plastic dome diffusors. Middle right of the photo. What use case have these dome diffusors, esp. as you lose about 2/3 of the light intensity. These are for free, but I am seeing these offered for other lights for real money. And I have lots of other comparable small diffusors or mini softboxes lying around from flashes I bought etc. I never used them, mainly because I couldn’t see a desirable effect and didn’t want to lose light.

But if these have little to no effect, mainly due to their size (soft light needs size I learned), why do people buy them, why do the manufacturers care about putting these into the package? Especially considering the loss of light these cause.

I have seen people using these for video and if asked they reply: they were in the package, they diffuse, must be something good, otherwise they wouldn’t add it. But in most cases, I assume, the loss of light is far worse than any added diffusion, if at all.

Any rational use case, where these would make sense? Maybe macro photography, where in relation to the sujét the light power is sufficient and the diffusor size really softens the light for the tiny sujét? Just curious.

These numbers are from Amaran for 5600K;

0,5 meter:

6,320 lux. With diffusor: 2,293 lux

1 meter:

1,636 lux. With diffusor: 580 lux.

 

[Jacques Cornell]

You're right that they don't actually soften the light. For that, you need to make your light source's apparent size much bigger, either by moving it closer or making it physically larger. I see two use cases for white domes, including the ones made for speedlights:

1. Make the light dimmer when at the dimmest setting. At very close distances, this could let you achieve softer light by moving it closer, as described above, without over-lighting the subject.
2. Spread the light across a wider angle of coverage.

 

[tugwilson]

The diffuser doesn't make the light softer it makes it more diffuse (i.e. it reduces the specularity). You generally don't want specular lighting if you have higly reflective surfaces.

In the Ace 25 case it also hides the separate emitters.

 

[Jacques Cornell]

The diffuser doesn't make the light softer it makes it more diffuse (i.e. it reduces the specularity).

That is an excellent distinction. Well-put.

You generally don't want specular lighting if you have higly reflective surfaces.

In the Ace 25 case it also hides the separate emitters.

 

[A-Marc]

it hides the LED´s, so they dont show up as refection on shiny surfaces.

it created a homogene square catchlight in the models eyes, if used as on axis fill.

--
https://www.flickr.com/photos/146973265@N06/
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http://www.fivedaggers.com

 

[DirkPeh]

You're right that they don't actually soften the light. For that, you need to make your light source's apparent size much bigger, either by moving it closer or making it physically larger. I see two use cases for white domes, including the ones made for speedlights:

1. Make the light dimmer when at the dimmest setting.
2. At very close distances, this could let you achieve softer light by moving it closer, as described above, without over-lighting the subject.
3. Spread the light across a wider angle of coverage.

Make the light dimmer…

Never thought of situations, where my lights need to be dimmer than the 1% the Amran offer. I guess this is the punishment for using continuous light for stills.

 

[DirkPeh]

The diffuser doesn't make the light softer it makes it more diffuse (i.e. it reduces the specularity). You generally don't want specular lighting if you have higly reflective surfaces.

In the Ace 25 case it also hides the separate emitters.

Is the loss of about 2/3 of the luminous intensity to be expected? I didn’t expect that much reduction, but fair if Amran reports the realistic values, 2300 lux with the dome diffuser vs. 6400 without at 0.5 meter.

With flashes I get the loss, but these small lights that rather serve as hair or fill lights besides macro photography, but are more and more used as main lights by v-loggers and younger photographers? They reach an astounding 32 watts in boost mode, but as impressive that is, they are still small and not much compared with strobes or flashes.

 

[A-Marc]

The diffuser doesn't make the light softer it makes it more diffuse (i.e. it reduces the specularity). You generally don't want specular lighting if you have higly reflective surfaces.

In the Ace 25 case it also hides the separate emitters.

Is the loss of about 2/3 of the luminous intensity to be expected? I didn’t expect that much reduction, but fair if Amran reports the realistic values, 2300 lux with the dome diffuser vs. 6400 without at 0.5 meter.

With flashes I get the loss, but these small lights that rather serve as hair or fill lights besides macro photography, but are more and more used as main lights by v-loggers and younger photographers? They reach an astounding 32 watts in boost mode, but as impressive that is, they are still small and not much compared with strobes or flashes.

LEE Filter White diffusion 216 eats 1 1/2 stops of light. So yes, the loss is to be expected.

 

[tugwilson]

Is the loss of about 2/3 of the luminous intensity to be expected? I didn’t expect that much reduction, but fair if Amran reports the realistic values, 2300 lux with the dome diffuser vs. 6400 without at 0.5 meter.

With flashes I get the loss, but these small lights that rather serve as hair or fill lights besides macro photography, but are more and more used as main lights by v-loggers and younger photographers? They reach an astounding 32 watts in boost mode, but as impressive that is, they are still small and not much compared with strobes or flashes.

The "loss" is to be expected. Of course some light will be consumed by the dome but mostly the light will be redistributed. If you hold it 1/2 metre away from a white wall in a darkened room you will see a very significant hotspot without the diffuser which disappears when the diffuser is on.

This is not a light to be used with strobes. Even a speedlight is going to overpower it unless you have extremely long exposure times. 32W with a shutter speed of 1/200th gives you around 0.16Ws. A speedlight at 1/256th is about a stop brighter.

 

[DirkPeh]

For sure nothing scientific, but this is the light at K5600 against a white wall, no boost mode, at 100%. Shutter speed, ISO, Aperture the same (1/125, 800, f/5.6) , with and without the dome. The metering of the cam showed about 0.7 difference.

Distance from the wall about 1,2 meters.

Without Dome Diffusor

With Dome Diffusor

Another try, slightly adjusted ISO to get the same metering. Distance light to figure 0.9 meter.

Without Dome at 100%, no boost. 1/320, ISO 250

With Dome. 1/250, ISO 320

 

[tugwilson]

I'm not sure I understand what you are trying to demonstrate here.

You've shown that without the dome you get a hotspot which mostly disappears with the dome.

You've shown that the dome requires an adjustment to the camera to get as good an exposure as without the dome.

You've shown that the dome reduces specularity.

None of these are surprising.

What other conclusions are you asking us to come to?

 

[DirkPeh]

I'm not sure I understand what you are trying to demonstrate here.

You've shown that without the dome you get a hotspot which mostly disappears with the dome.

You've shown that the dome requires an adjustment to the camera to get as good an exposure as without the dome.

You've shown that the dome reduces specularity.

None of these are surprising.

What other conclusions are you asking us to come to?

I have expected a more radical difference between 1 and 2, exact same camera settings, supposing that I loose 2/3 of the light with the dome. To me it’s just weaker, but I don’t see much difference in the quality or texture of the light.

Same for pictures 3 and 4. I aimed for an equal exposure and lowered the shutter speed 320 to 250 and raised the ISO from 250 to 320. 2 is still a bit less exposed, the metering jumped between -0.3 and 0. But I don’t see a significant difference.

Another aspect that surprised me is that with the small video light as the only light source, I get away with such high shutter speeds and low ISO on a 50 mm full frame with f/2.5, even when using the dome and don’t even activate the boost mode (25 -> 32 watts) on the small light.

 

[tugwilson]

You're not really losing 2/3rds of the light. There will be some diminution but mostly the light is being redistributed.

 

[A-Marc]

I'm not sure I understand what you are trying to demonstrate here.

You've shown that without the dome you get a hotspot which mostly disappears with the dome.

You've shown that the dome requires an adjustment to the camera to get as good an exposure as without the dome.

You've shown that the dome reduces specularity.

None of these are surprising.

What other conclusions are you asking us to come to?

I have expected a more radical difference between 1 and 2, exact same camera settings, supposing that I loose 2/3 of the light with the dome. To me it’s just weaker, but I don’t see much difference in the quality or texture of the light.

tugwilson already said about the hot spot in the center, thats a very noticeable difference. The light does get scattered over a bigger area, reducing the hot spot in the center.

The next difference is in the specular highlights, they appear less crisp (call it bit of dull). A big misunderstanding is that the light with diffusion is "softer", thats not the case. When we talk about soft light, we refer to the shadow transition. When you look at the shadow your TV does cast on the wall, the transition from dark to light does stay the same, the diffusor does not change the characteristic of the shadow transition. Only a bigger light source would change this characteristic.

Same for pictures 3 and 4. I aimed for an equal exposure and lowered the shutter speed 320 to 250 and raised the ISO from 250 to 320. 2 is still a bit less exposed, the metering jumped between -0.3 and 0. But I don’t see a significant difference.

your metering reflected light, your camera averages out the exposure at 18% Gray. Thats common to do so with natural light. In Studio, or with flash, we meter the incident light. so to say, when we talk about light, its the light what actually hits the subject. Most of the time we do not talk about the in camera metering.

Another aspect that surprised me is that with the small video light as the only light source, I get away with such high shutter speeds and low ISO on a 50 mm full frame with f/2.5, even when using the dome and don’t even activate the boost mode (25 -> 32 watts) on the small light.

these things drastically change when you have to move the light away from the subject, and or you like to shoot narrow apertures. give it a try, its a great way to learn about light.

Hope that helps with understanding whats happening here.

 

[Ellis Vener]

They are useful when used very close to what you are lighting with it. By very close, I mean no further away than 2x the diagonal.

 

[DirkPeh]

They are useful when used very close to what you are lighting with it. By very close, I mean no further away than 2x the diagonal.

Thank you. In picture 3 and 4 the light was 0.9 meter away and not in boost mode and allowed 1/350 ISO 250 at f/2.5! The diagonal of the light is 11 cm / 0.11 meter.

But it goes from 6400 lux at 0.5 meter to only 1.700 at 1 meter.

 

[Ellis Vener]

Max brightness is not typically my main concern when I am using a light close to a subject.

 

[Victor Engel]

They are useful when used very close to what you are lighting with it. By very close, I mean no further away than 2x the diagonal.

That's what I was going to say. My own use would be high magnification macro, but for such a case, usually the diffuser goes around the subject.

This reminds me of glamour shots taken with ring lights. The specular reflections in the eyes are really distracting in my opinion. Such a setup seems quite popular, though.