Question about Eyes and Flash powerful.

[SergeiR]

But there's no energy there...

there is, actually.

Basically people can go blind by doing plenty of stupid things (i had shot myself in the eye with toy revolver when i was a kid). As long as one is thinking about it - its all fine.

I shoot with 1200ws flashes all the time, actually. I do smell ozone of those guys, when you close and you feel like your eyebrows gone, if it pops too close. But 1 meter distance is more or less ok.

If OP planning to use that to shoot collodion i can tell you right away from experience with dry plates that you dont need full blast on those guys to get enough light to shoot with f5.6/4.5. Certainly not at the 1m distance (you get in area of f128 pretty damn fast).

[SergeiR]

Also it might be cheaper and easier to just build up fluorescent light rig, like in old days

[E. von Hoegh]

there is, actually.

Basically people can go blind by doing plenty of stupid things (i had shot myself in the eye with toy revolver when i was a kid). As long as one is thinking about it - its all fine.

I shoot with 1200ws flashes all the time, actually. I do smell ozone of those guys, when you close and you feel like your eyebrows gone, if it pops too close. But 1 meter distance is more or less ok.

If OP planning to use that to shoot collodion i can tell you right away from experience with dry plates that you dont need full blast on those guys to get enough light to shoot with f5.6/4.5. Certainly not at the 1m distance (you get in area of f128 pretty @#!*% fast).

That was sarcasm, Sergei.

[jp]

I have a tiny bad spot in one of my eyes from eposure to a welding torch (not an arc). Were my opthalmologist (not optometrist) to tell me what yours told you, I'd leave the office immediately and permanently and find a new eyeball doctor.

I got a real bad sunburn once from arc welding. My apron wasn't high enough and got a nice v-shaped burn above the apron and under my mask. But it happened over a whole evening of welding, not a fraction of a second. The deal with any sort of welding, is that the light is a point source, like a magnifying glass burning an ant when the light would have been harmless otherwise. Spread that out with a reflector or modifier and it's not an extreme point source of light anymore. It's the point source that hurts your eyes (like a laser beam), not the quantity of light.

The advice about looking away, I'd not trust for welding, but would for flash. The amount of light needed to illuminate an indoor stadium is immense. Yeh, there's the inverse square law, but they use a very large amount of strobes to light the place.

This is an interesting topic.. I personally wouldn't risk spending thousands of dollars on monster speedotron flash only to upset my friends and relatives such that they'd never pose for me again if the flash were uncomfortable.

[E. von Hoegh]

I got a real bad sunburn once from arc welding. My apron wasn't high enough and got a nice v-shaped burn above the apron and under my mask. But it happened over a whole evening of welding, not a fraction of a second. The deal with any sort of welding, is that the light is a point source, like a magnifying glass burning an ant when the light would have been harmless otherwise. Spread that out with a reflector or modifier and it's not an extreme point source of light anymore. It's the point source that hurts your eyes (like a laser beam), not the quantity of light.

The advice about looking away, I'd not trust for welding, but would for flash. The amount of light needed to illuminate an indoor stadium is immense. Yeh, there's the inverse square law, but they use a very large amount of strobes to light the place.

This is an interesting topic.. I personally wouldn't risk spending thousands of dollars on monster speedotron flash only to upset my friends and relatives such that they'd never pose for me again if the flash were uncomfortable.

There's also quite a lot of UV and IR present at levels not found in other common sources, point or otherwise. What got me was the fact that a cutting torch uses oxygen at pressure to burn the metal it cuts - the metal becomes the fuel to cut itself, the oxyacetylene flame is just to get the steel hot enough that it will react with the oxygen.

[BrianShaw]

The impact and hazards of photons on eye/retina/skin has not gone unrecognized. This is controlled by FDA/CDRH in USA and I believe regulated through equivalent ISO guidelines in other parts of the world.

Product liability laws take care of the rest.

Generically speaking I understand what you say. But can you please point me to an applicable example of FDA regulation or ISO guidelines for photographic strobe exposure? I have searched the internet and found plenty on UV and bright light exposure from constant source exposure and "flash blindness"... all of which are real and well-understood problems... but nothing specific to photographic strobes. If so well understood and controlled, I would expect warning labels, etc. The internet is either ignorant of this information or I'm searching for it in the wrong places. I actually have advanced degree in areas relating to this and product liability... but for some reason I have never had chance to work this specific area professionally and not finding much as I casually search for "data" to supplement the intelligent opinion.

[BrianShaw]

... This is an interesting topic.. I personally wouldn't risk spending thousands of dollars on monster speedotron flash only to upset my friends and relatives such that they'd never pose for me again if the flash were uncomfortable.

amen.

[Amedeus]

But can you please point me to an applicable example of FDA regulation or ISO guidelines for photographic strobe exposure?

Brian, There is none because there's none needed for flash photography from a scientific/medical perspective. Normal use of high powered photography flash lamps is not going to burn your retina nor cornea. Flash lamps are not good "point sources", so there's insufficient optical coupling with a retina to cause a burn under normal application circumstances. There are a quite a number of factors playing here.

It's a different story for lasers (typically collimated and coherent) as that source is easily focussed on the retina to spot sizes of 100 micron or less ... I've seen a few cases of permanent eye damage with laser light but never with incoherent light. Temporary flash blindness from pulsed or continuous light sources is a different story

UV exposure (sun or a welding source) damages the eye in a different way ... the invisible radiation is mostly absorbed by the cornea (not retina ... ) and that can cause corneal damage.

Retinal absorption of visible to near infrared (400-1400nm) can lead to permanent injury. That's why you don't stare in the sun for prolonged periods of time, that's why you don't point a laser of any power at someone ... the sun is a good point source from the distance we're viewing it and our normal aversion for bright lights will either force us to close the eyes or turn our head away. The only reason why Class I lasers are considered "safe" is that it is assumed the human blink reflex to take care of "over-exposure" and associated risk for retinal damage. (All bets are off if you force a stare in a Class I laser ... not recommended and permanent damage is possible.)

I've been all my professional life around lasers (up to 40W visible) and extremely bright light sources, both continuous (up to 18kW) and flashed (well over 6kJ). No retina burns, no cornea burns.

[BrianShaw]

Brian, There is none because there's none needed for flash photography from a scientific/medical perspective. Normal use of high powered photography flash lamps is not going to burn your retina nor cornea. Flash lamps are not good "point sources", so there's insufficient optical coupling with a retina to cause a burn under normal application circumstances. There are a quite a number of factors playing here.
...

Thanks for the clarification. I misunderstood your earlier post and thought you meant that there was governmental/industry guidance regarding photographic strobes.