Is 4800ws in a standard reflector too bright for the eyes?

Qebs · Jul 8, 2021

Greetings,

Could somebody tell me if 4800ws is too bright for the eyes if it's in a standard reflector about 4 feet away?

I'm slowly trying to get into alternative analog processes and will need a lot of light but don't want to damage people's eyes.

I know some wet plate people use 4800ws or 9600ws but they are using light softening modifiers and
I would like to try some direct lighting.

Thanks so much!
Be well

Best Regards,
Kevin H.

Pieter12 · Jul 8, 2021

Geez, that's a lot of joules! When Chuck Close made a series of daguerreotype portraits, he used six flash strobes to make the exposure almost instantaneous. According to him, "Your eyes slam shut so fast, it feels like somebody stuck an ice pick into the middle of your eye. If we don't have the shields, you can smell your hair and your face burning." I haven't seen any information about how powerful the strobes were.

AnselMortensen · Jul 8, 2021

My immediate response:
"OMG, Yes!"

Adrian Bacon · Jul 9, 2021

Qebs said:
Greetings,

Could somebody tell me if 4800ws is too bright for the eyes if it's in a standard reflector about 4 feet away?

I'm slowly trying to get into alternative analog processes and will need a lot of light but don't want to damage people's eyes.

I know some wet plate people use 4800ws or 9600ws but they are using light softening modifiers and
I would like to try some direct lighting.

Thanks so much!
Be well

Best Regards,
Kevin H.

1000ws in a standard reflector 3-4 feet away is enough that people feel quite cooked when that thing fires. You can feel 500ws quite a bit at full power at that distance. 4800ws? I’d be careful about a whether you actually need that much power. Having that much fire on you is a whole lotta no fun.

wiltw · Jul 9, 2021

I have a Dynalite M2000 power pack...2000w-s.
Years ago I measured my Dynalite M2000 which has 2000 w-s of power into a Dynalite 4040 head, and at ISO 200 it was about GN380, or f/38 at 10'
4000 w-s would be about GN538, or f/54 at 10'

Adrian Bacon · Jul 9, 2021

wiltw said:
I have a Dynalite M2000 power pack...2000w-s.
Years ago I measured my Dynalite M2000 which has 2000 w-s of power into a Dynalite 4040 head, and at ISO 200 it was about GN380, or f/38 at 10'
4000 w-s would be about GN538, or f/54 at 10'

ive been on the receiving end of 500ws at full power in a standard reflector at 3-4 feet. It’s not that pleasant. It’s not so much how bright it is, it’s the amount of heat you get put on you.

Qebs · Jul 9, 2021

Thanks everyone for your input.

May I will plan to stick with using a large light modifier like what others already do for wetplate collodion.

Thanks again!
Be well.
Have a great weekend!
Cheers,
Kevin H.

wiltw · Jul 9, 2021

Qebs said:
Greetings,

Could somebody tell me if 4800ws is too bright for the eyes if it's in a standard reflector about 4 feet away?.

We need some clarification...are you wanting to use a source which is

4800 Watt-seconds of instantaneous output strobe (electronic flash)
4800 Watts of constant light output halide bulb

Very different animals!

Qebs · Jul 9, 2021

Hey wiltw,

I'm hoping to use my 4800ws Speedotron for direct positive color reversal for fun and maybe as an on going project if I like or accept the wonky colors and mottling.

I like the editorial/magazine look with direct flash (where the light is sitting right above the lens).

Since ISO is around 1-3, from my calculations, it seems I don't want the light further than 4 feet from the subject.
To get the camera 4 feet away I think I need a 240mm lens for my 8x10 format camera.

I just don't know if the light will be too bright as a point light source.
I remember though, that people on a some forum said that if you make the light bigger, it's less dangerous for the eyes.
So, I know at least I can use an umbrella or softbox/octabox. I'm going to test with a light meter tonight to see how many tops I loose with the diffusion layers in my softbox at ISO 3 / f/5.6 with the light as close as possible. (with Alien Bees)

But yesterday I found a competitor to the Arri SkyPanel s360c, the SpaceX by creamsource.com.
The Spacex is a 1200 watt LED light.
I contacted the manufacturer and they did some light metering tests for me and they got:

light to subject distance 3 feet
ISO 3
f/5.6
Shutter Speed 1/8 - 1/2 second depending on narrow beam vs wide beam vs diffusion layer used.

The only issue is that It would end up costing me 9000 Canadian dollars to get setup and I would like to test the strobes
first (Waiting to find time to get my Speedotron powerpacks to a repair shop for service/checkup).

What do you think I should do Wiltw? Stick with the strobe and avoid direct light lighting?
And if the strobes with a softbox modifier is still to uncomfortable/dangerous, I guess I can sell some toys and
buy the LED light.

Thanks for your time again
Be well!
Kevin H.

wiltw · Jul 9, 2021

Qebs said:
Hey wiltw,

I'm hoping to use my 4800ws Speedotron for direct positive color reversal for fun and maybe as an on going project if I like or accept the wonky colors and mottling.
light to subject distance 3 feet
ISO 3
f/5.6
Shutter Speed 1/8 - 1/2 second depending on narrow beam vs wide beam vs diffusion layer used.
What do you think I should do Wiltw? Stick with the strobe and avoid direct light lighting?
.

I have no experience with what you are doing, so I cannot offer suggestion.
I recently read something about wet colloidian exposure and the recommendation was, "Closer you eyes during exposure."

I asked about source type simply because 1000W halide outputs 110,000-120,000 lumens of light, and bulbs are $25 apiece.

About eye damage:

"In experimental mice, bright light does cause permanent retinal damage. If the light has the intensity of sunlight, short exposure times can cause damage. If the light is not quite so bright, chronic exposure over days to weeks can cause permanent damage. This is thought to be due to what is called photo-oxidative damage; the light reacts with the retina to produce molecules that are very reactive and cause damage to surrounding molecules."

"Is the flash safe?
"Ultimately, yes, a camera’s flash is very safe for our eyes. This is due to three main factors: exposure, intensity, and focus. As most camera flashes last for just 1/400th of a second (although it might feel like a lot longer!), our exposure to the flash is very small. Even if someone took ten flash photos of you in a row, there would be no damage. Some studies show it takes around 100 seconds of looking at bright light for permanent damage to be done to the retina, while other sources suggest the limit is around 30 seconds. While there is some disparity here, we know that camera flashes don’t last for 30 seconds, let alone 100 seconds. Even if it’s a particularly long photo shoot, there are small breaks in between shots and flashes. These gaps are enough to ensure that your retina isn’t permanently damaged."

How many lumens will damage your eyes?

"Safe to say the amount of lumens needed to damage your eye is in the tens of thousands, as anything over 4000 will make you squint, and anything in the hundred thousands is in laser territory. A good rule-of-thumb is, if it hurts then look away."

Chan Tran · Jul 9, 2021

Qebs said:
Hey wiltw,

I'm hoping to use my 4800ws Speedotron for direct positive color reversal for fun and maybe as an on going project if I like or accept the wonky colors and mottling.

I like the editorial/magazine look with direct flash (where the light is sitting right above the lens).

Since ISO is around 1-3, from my calculations, it seems I don't want the light further than 4 feet from the subject.
To get the camera 4 feet away I think I need a 240mm lens for my 8x10 format camera.

I just don't know if the light will be too bright as a point light source.
I remember though, that people on a some forum said that if you make the light bigger, it's less dangerous for the eyes.
So, I know at least I can use an umbrella or softbox/octabox. I'm going to test with a light meter tonight to see how many tops I loose with the diffusion layers in my softbox at ISO 3 / f/5.6 with the light as close as possible. (with Alien Bees)

But yesterday I found a competitor to the Arri SkyPanel s360c, the SpaceX by creamsource.com.
The Spacex is a 1200 watt LED light.
I contacted the manufacturer and they did some light metering tests for me and they got:

light to subject distance 3 feet
ISO 3
f/5.6
Shutter Speed 1/8 - 1/2 second depending on narrow beam vs wide beam vs diffusion layer used.

The only issue is that It would end up costing me 9000 Canadian dollars to get setup and I would like to test the strobes
first (Waiting to find time to get my Speedotron powerpacks to a repair shop for service/checkup).

What do you think I should do Wiltw? Stick with the strobe and avoid direct light lighting?
And if the strobes with a softbox modifier is still to uncomfortable/dangerous, I guess I can sell some toys and
buy the LED light.

Thanks for your time again
Be well!
Kevin H.

Are you photographing people? If not then it doesn't matter. Just look away during the exposure.

Pieter12 · Jul 9, 2021

Qebs said:
So, I know at least I can use an umbrella or softbox/octabox.

I don't think you will get the look you want with an umbrella or soft box. It will have to be above the camera, so above the subject by at least 1/2 the diameter or short dimension of the soft box. Ringlight, maybe? But I don't think there are any 4800WS ringlights made. You could try to fashion a custom soft box out of foam core that fits around the camera...it would take some fiddling to do, but should be possible. I would be more concerned about that much light only 4 feet from the subject. And don't stand near it, either. It will generate a lot of noise...I only use 1500 WS and it makes a pretty big "pop!"

Qebs · Jul 9, 2021

Thanks wiltw for researching a bit to help!
You are too kind with your time Sir!
Yep, I did wonder and look into hot/tungsten lights.
I like the LEDS because I can control the color temperature to dial in the RA4 paper colors (with out printing/darkroom gels).

I should have stated I'm not looking for medical advice as my question (s)
might deter people from answering.

I'm looking at lumens to watts conversion to better understand but
I don't think I'm doing it right.

Using this calculator and chart, it seems a 1000 watt halide lamp should give more lumens than 10K-12K.
https://www.rapidtables.com/calc/light/lumen-to-watt-calculator.html

I'm looking at this website to better understand lumens/seconds and such but my math is horrible these days.
https://photo.stackexchange.com/questions/77356/how-to-calculate-light-output-from-strobe-lights

It seems 4800 ws strobes put out a wild amount of lumens, but I know Speedotron systems have very short durations.

Hmm... still not sure if Strobes are safe.

~~~

Hello Chan Tran, yep, I would be taking portraits of people. (sorry, I should have wrote that)

~~~

Hi, Pieter12, awesome suggestion, I too was thinking of a DIY ring flash, but it's a different look than direct flash.
Oh, I didn't mean to try to replicate direct flash with a softbox. I just think I might want to forget about direct flash and just stick with softboxes with rembrandt, loop, split lights etc...

Thanks for the warning, yep, I'm starting to think 4800 ws at 4 feet is not safe for the subject.

~~~

I guess if the 4800 ws heads or my 9600 ws heads are too bright even in a diffused large light modifier,
I guess I can get rid of some toys and but that 1200 watt LED light.

Thanks everyone, have a great weekend!

wiltw · Jul 9, 2021

Qebs said:
I'm looking at lumens to watts conversion to better understand but
I don't think I'm doing it right.

Using this calculator and chart, it seems a 1000 watt halide lamp should give more lumens than 10K-12K.
https://www.rapidtables.com/calc/light/lumen-to-watt-calculator.html

I'm looking at this website to better understand lumens/seconds and such but my math is horrible these days.
https://photo.stackexchange.com/questions/77356/how-to-calculate-light-output-from-strobe-lights

It seems 4800 ws strobes put out a wild amount of lumens, but I know Speedotron systems have very short durations.
!

There IS NO DIRECT conversion between

units of electricity pulled from the wall to charge a power capacitor
:Lumens of light that come out any ANYTHING!

Proof statements of above fact:

Loolk up 60W incandescent bulbs of different brands and even models and they are different in the Lumens they output
Chimera (softbox company) decades ago proved that 1000 w-s rated power packs from many different brands did NOT all have similar outputs, as measured by lightmeters...a 1000 w-s Dynalite was measured at about +1EV more light than a 1000 w-s Speedotron or TWICE as much light, for example.
If you merely put longer extension cables between head and pack, the power will drop due to losses in the cabling
Different heads have different efficiency in coverting a given amount of electricity to a variable intensity of light, because of reflector shape and coverage angle, reflector surface, lack of reflector
So-called 60W equivalent LED bulbs use from 6W-9W to produce 700-800 Lumens of light.

Qebs said:
Using this calculator and chart, it seems a 1000 watt halide lamp should give more lumens than 10K-12K.
https://www.rapidtables.com/calc/light/lumen-to-watt-calculator.html

Oops! typos... 110,000 Lumens and 120,000 Lumens (earlier post edited)

jacaquarie · Jul 9, 2021

I am offering the opinion from a different viewpoint.
My thoughts are this is way too intense for the human eye.
In my past I had arc welded and have had the "flash burn", think sunburn but on the inside of the eye.
Not fun.
Since you are asking the questions, my impression is you have doubts of how safe is this?
If in doubt do not!
I have had experience with something similar to what you are doing in the industrial situation. You would be impressed with the multiple interlocks to prevent the exposure to the light.
If you think this is safe then you expose yourself to light of this intensity. Wear safety glasses.
Think about what happens if a bulb lets go.

had my say, be smart!

AgX · Jul 10, 2021

Squinting should be out of the discussion here, as in any case it would come too late at 1/500th or shorter flash duration.

Qebs · Jul 10, 2021

wiltw, thanks! I barely remember reading what you are saying but it's all a bit confusing haha.
~~~
jacaquarie, do you mean direct flash is too dangerous or even using a softbox with diffusion layers?

~~~

Thanks Agx!

wiltw · Jul 10, 2021

Qebs said:
wiltw, thanks! I barely remember reading what you are saying but it's all a bit confusing haha.
~~~
jacaquarie, do you mean direct flash is too dangerous or even using a softbox with diffusion layers?

~~~

Thanks Agx!

To refresh your memory with what was posted earlier:

"Is the flash safe?
"Ultimately, yes, a camera’s flash is very safe for our eyes. This is due to three main factors: exposure, intensity, and focus. As most camera flashes last for just 1/400th of a second (although it might feel like a lot longer!), our exposure to the flash is very small. Even if someone took ten flash photos of you in a row, there would be no damage. Some studies show it takes around 100 seconds of looking at bright light for permanent damage to be done to the retina, while other sources suggest the limit is around 30 seconds. While there is some disparity here, we know that camera flashes don’t last for 30 seconds, let alone 100 seconds. Even if it’s a particularly long photo shoot, there are small breaks in between shots and flashes. These gaps are enough to ensure that your retina isn’t permanently damaged."

Arc welding is a very different animal than 1/400 burst duration flash.
Your mention of Speedotron took the issue out of the realm of very bright constant source, like four 1000W halide bulbs.

AgX · Jul 10, 2021

wiltw said:
Some studies show it takes around 100 seconds of looking at bright light for permanent damage to be done to the retina, while other sources suggest the limit is around 30 seconds.

What is "bright" light in those studies?

With flaslight the energy necessary for let's say 1/10 second with continuous lighting is applied in about 1/1000 second. So in this example we are speaking of difference of already 2 magnitudes.

Also a longterm application of energy versus an impuls application of same energy cannot be easily compared, as non-reciprocal effect are to be expected. Just think of the lacking cell/tissue cooling at impuls application.

Qebs · Jul 10, 2021

Hey peeps, thanks for your continued help.

I asked a wet plate photographer on Facebook how it's like working with 9600 watt second strobe heads in softboxes.
They said, you get blurry and disturbed color artifacts in your vision for a few seconds but it goes away.
I'm not sure if this is acceptable treatment of one's subjects.
I'm reaching out to people in different ways if I can make one of these safely/better engineered (but also with color changing abilities):
(A diy LED light panel - 4000 LEDs at 1000 watts)

Have a good weekend!
Cheers

Pieter12 · Jul 10, 2021

Maybe you should shoot a few self-portraits with the lighting you plan to use, just so you know what your subject might be experiencing.

gone · Jul 10, 2021

That "study" which stated that it took exposures of over 100 seconds to permanently damage the retina is preposterous. Even brief exposure to a solar eclipse can cause permanent eye damage or blindness. I was once a welder myself, and can assure you that looking at that arc for 100 seconds w/o a shield will make you as blind as a bat.

Being near a lot of voltage, even for brief periods, is hazardous in itself.

wiltw · Jul 10, 2021

momus said:
That "study" which stated that it took exposures of over 100 seconds to permanently damage the retina is preposterous. Even brief exposure to a solar eclipse can cause permanent eye damage or blindness. I was once a welder myself, and can assure you that looking at that arc for 100 seconds w/o a shield will make you as blind as a bat.

Being near a lot of voltage, even for brief periods, is hazardous in itself.

AgX raised the right question, "How much light is 'bright light' for 100 sec. to be threshhold of damage?" (which I do not posssess the answer, since that is not my statement) The original quote was taken from and eye surgery website.
https://www.optimax.co.uk/blog/photo-flash-damage-eyes/
and the key to that statement is "some studies show" is linked to https://scienceline.ucsb.edu/getkey.php?key=3269

momus said:
I was once a welder myself, and can assure you that looking at that arc for 100 seconds w/o a shield will make you as blind as a bat

IIRC, welder glasses (level 11) will not protect your eyes from arc welding and from the sun., they need to be the very darkest lens, Level 14 for sun protection...not 'the same' but both pretty dammed bright.

AgX · Jul 11, 2021

This quotation from the first source tells all about its validity:
"Further to this, eye doctors frequently shine torches into their patients’ eyes to check their eye health, particularly when assessing the pupil size. These examinations expose your eyes to a light as bright as a photo flash, but for a much longer period."

Pieter12 · Jul 11, 2021

AgX said:
This quotation from the first source tells all about its validity:
"Further to this, eye doctors frequently shine torches into their patients’ eyes to check their eye health, particularly when assessing the pupil size. These examinations expose your eyes to a light as bright as a photo flash, but for a much longer period."

I think this quote puts everything in the article in doubt: "Most modern day flashes use relatively low wattage LED bulbs."

Is 4800ws in a standard reflector too bright for the eyes?

Attachments

Privacy & Transparency

Privacy & Transparency