# Can a (DSLR) flash cause permanent eye damage?



## sandymandy (Jun 7, 2013)

Hi,

out of curiosity and since i just remembered as a kid i accidently fired off my compact camera flash directly in front of my eyes ( : ) im wondering if permanent eye damage is possible with my inbuilt 1100D camera flash for example. Some external flashes are able to burn plastic bags as can be seen on youtube. Oh and the compact camera flash just gave me purple vision for some time but nothing permanent.

Just wanna see some calculations of the mathematics/physics experts here (i suck at this) like

1.) Whats the minimum flash power needed to cause retinal burn or other permanent damage

2.) If its even possible to happen in real cuz light travels different inside the eyeball onto the retina than in the air i guess etc.

im just curious so please satisfy my scientific needs


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## bycostello (Jun 7, 2013)

yes.. but you'd have to be an idiot to get that close and powerful...


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## SwissBear (Jun 7, 2013)

a fully powered 580EX II can leave some patterns for about week or so on stressed eyes.

By stressed eyes i mean 3-5 days in row 1-2 hours exposure to direct sunlight in a snowy environment at midday at high elevation (no sane person would do this, we told all the kids is was mandatory to wear some eye protection during the midday ski break, but some would not listen).

Sometimes, communication between my 600D and the flash clogs up and it goes of at 1/1, thats how i "tested" it. 

But then again, i guess that also a starting fluorescent tube would have caused trouble to these two kids.

But as the flash in the 1100D has less than a forth of the power of the 580EX II, you might get some patterns in your eyes that last for maybe some hours if you fire a 1/1 flash at close distance in pitch black environment.

For physical background: all i remember is that the amount of light is proportional to the square of the distance to the light source. (double the distance results in 1/4 lightpower)


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## Mt Spokane Photography (Jun 7, 2013)

The Press 25 bulbs that everyone used to use did not cause damage, and they gave off extremely bright for a far longer time than the 1/10,000 sec of a electronic flash. I have a few dozen of them stashed away. They keep getting more and more valuable every year.

And then there were the Sylvania FF33 bulbs.
http://www.flashbulbs.com/CresImgs/PagePics/MegaFlsh/PF3300_350.gif


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## nvsravank (Jun 7, 2013)

For newborns yes they can hurt. Try to minimize for newborns and babies. For adults you have to really try hard to damage, but it is possible. Kids are more susceptible. So not too many flashes on them.


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## unfocused (Jun 7, 2013)

If there were any risk of permanent eye damage the American trial lawyers would be all over this like white on rice.


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## AudioGlenn (Jun 7, 2013)

I too am curious about 3rd party batteries for my mk3. I had 2 wasabi batteries for my T3i when I owned one and they worked well but I only had that camera for about 5 months before I sold it.


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## Skirball (Jun 7, 2013)

I'm confident that if you place the flash physically on the eye and fire it will cause permanent damage. Caveat Emptor.


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## jdramirez (Jun 7, 2013)

we need to get Adam and Jamie on this... during sweeps weeks when all the gloves are off of what they are allowed to do.


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## GuyF (Jun 7, 2013)

I recently saw a programme about Nobel prize winning physicist Richard Feynman who worked on the Manhattan project to build the first nuclear bomb. He said, "They gave out dark glasses that you could watch it with. Dark glasses! Twenty miles away, you couldn’t see a damn thing through dark glasses. So I figured the only thing that could really hurt your eyes (bright light can never hurt your eyes) is ultraviolet light. I got behind a truck windshield, because the ultraviolet can’t go through glass, so that would be safe, and so I could see the damn thing.

Time comes, and this tremendous flash out there is so bright that I duck, and I see this purple splotch on the floor of the truck. I said, “That’s not it. That’s an after-image.” So I look back up, and I see this white light changing into yellow and then into orange. Clouds form and disappear again – from the compression and expansion of the shock wave.

Finally, a big ball of orange, the center that was so bright, becomes a ball of orange that starts to rise and billow a little bit and get a little black around the edges, and then you see it’s a big ball of smoke with flashes on the inside, with the heat of the fire going outwards.

All this took about one minute. It was a series from bright to dark, and I had seen it. I am about the only guy who actually looked at the damn thing – the first Trinity test. Everybody else had dark glasses, and the people at six miles couldn’t see it because they were all told to lie on the floor. I’m probably the only guy who saw it with the human eye."

So there you go, as long as there's a sheet of glass between you and the light, you _might_ be fine 8)


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## Mt Spokane Photography (Jun 7, 2013)

Skirball said:


> I'm confident that if you place the flash physically on the eye and fire it will cause permanent damage. Caveat Emptor.


 
Actually, for certain types of eye exams, they do place a ring flash and camera on your eye to photograph the retina. My Retina specialist does it every day with no issues.

If the light is strong enough and lasts long enough, as in a arc welder, your cornea will get burned.

Time of exposure, wavelength as well as brightness are factors.
http://doctor.ndtv.com/faq.aspx?fid=6852


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## Skirball (Jun 7, 2013)

Mt Spokane Photography said:


> Skirball said:
> 
> 
> > I'm confident that if you place the flash physically on the eye and fire it will cause permanent damage. Caveat Emptor.
> ...



Obviously the level of brightness of the light will have an impact, but that's not what I was referring to. Have you ever placed a speedlight on your skin and fired it?


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## sunnyVan (Jun 7, 2013)

A friend of mine is an eye MD. I'll see if I could remember to ask him when I see him. 

I suspect damage is possible if a powerful flash is firing directly at the eyes and the eyes happen to focus on directly on the light source. 

By the way, if you open the aperture all the way and point the camera directly at a bright sun, can it damage the sensor?


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## Skirball (Jun 7, 2013)

sunnyVan said:


> By the way, if you open the aperture all the way and point the camera directly at a bright sun, can it damage the sensor?



It's the same answer as the flash and the eye.


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## sunnyVan (Jun 7, 2013)

Skirball said:


> sunnyVan said:
> 
> 
> > By the way, if you open the aperture all the way and point the camera directly at a bright sun, can it damage the sensor?
> ...



Kind of. But there's difference too. The eye can only regulate amount of light coming in by changing size of iris. Camera has iso, aperture, and shutter speed. To destroy the sensor I think you must be in manual mode and deliberately expose. 

When a flash fires at the eyes, they blink but not fast enough to keep out the immense amount of light. The iris contracts but probably not fast enough either. 

Therefore I think it's much harder to mess up the sensor than the eyes by intense light. Just my two cents.


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## Jules (Jun 7, 2013)

Answer is plain and easy : yes, it can ! And I know the effects firsthand :-(

Some would say it looks like one of these Wile.E Coyote cartoon ... but recipe is easy... wanting to experiment with Photography can be tempting....
Take somebody who is a bit light sensitive (years in Texas with probably poor grade sunglasses didn't help), have fun at night with photo friends for a "lighpainting session" (ie. taking picts with lights effects at night), and fire a 430EX external flash at your face from 30-40cm below, and don't close your eyes .... 
=> result is really cool "ghost like picture" like in the books (ie. your camera set on long exposure takes picts with 3 times your face for example if you move and redo it, just the face that was under flash exposure, rest of the body is invisible and you see the background thru ...), but better if you close your eyes and/or look up instead of looking in front or worst, low at your flash (like the first tries to see where to position it best, etc ...)
=> side effect after multiple attempts in the evening is darker spot in your eyes, showing "paler" zones when looking at lights (and having focus shift left/right) as if you had a water spot on the eye diffracting light a bit, and showing "greyer" areas when looking at uniform white wall (or blue sky) with high luminosity ...


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## jdramirez (Jun 7, 2013)

now I feel bad.. Iwas at a minor league baseball game and taking photos of my daughter andher friends. and some kid asked me to take his picture, so I hit the flash pilot and he wasn't blind immediately thereafter... but in retrospect maybe the next day.


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## Skirball (Jun 7, 2013)

sunnyVan said:


> Skirball said:
> 
> 
> > sunnyVan said:
> ...



I wasn’t referring to the mechanics of it, just the answer. Which in my opinion is: no, for the most part. Typical use of flash won’t blind people or you’d know of it. Flashes would come with huge warnings, flash photography would be heavily controlled, if popular at all. It’d be like going to a laser light show. Likewise, despite all the talk online of the sun damaging sensors there is surprising little evidence of actual damaged cameras. Sure, if you get a really bright flash and stand inches from it staring into it and let the flash rip you could feasibly damage your eye. Point your camera directly at the sun and take some long exposures and I could see damaging the camera. But if you use common sense it won't be an issue. Neither of these are looming perilous threats ready to claim hordes of unsuspecting victims; news at 10.


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## Mt Spokane Photography (Jun 7, 2013)

Jules said:


> Answer is plain and easy : yes, it can ! And I know the effects firsthand :-(
> 
> Some would say it looks like one of these Wile.E Coyote cartoon ... but recipe is easy... wanting to experiment with Photography can be tempting....
> Take somebody who is a bit light sensitive (years in Texas with probably poor grade sunglasses didn't help), have fun at night with photo friends for a "lighpainting session" (ie. taking picts with lights effects at night), and fire a 430EX external flash at your face from 30-40cm below, and don't close your eyes ....
> ...


 
Seeing dark spots after being exposed to a bright light is common, but its not permanent damage to your eyes.


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## GuyF (Jun 8, 2013)

Like I said, Richard Feynman viewed a nuclear test through just a car windshield and didn't report damage to his eyes. Is there any flashgun available that is brighter than a nuke?


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## Marsu42 (Jun 8, 2013)

sunnyVan said:


> A friend of mine is an eye MD. I'll see if I could remember to ask him when I see him.



Please do, I'd really like to get a competent opinion on this - my personal guess is that apart from pre-damaged eyes it's hard to do *permanent* (not long-lasting) damage short of point blank flash or a nuclear explosion, but then again I could be mistaken.


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## sandymandy (Jun 8, 2013)

Well lasers can cause permanent eye damage and they arent near the power of a nuke for sure 

Im just curious not only when using a flash in the normal way but also in a "not normal" way for example. Just the theory behind it and possibility.

I also dont think staring in the sun can cause blindness. Scotoma yes (i got scotoma on both eyes btw) but its not like im not able to see anymore just some parts are missing (replaced by some flickering spots in my case)


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## Jules (Jun 8, 2013)

Well, i'd say after more than 2 years it can be considered quite permanent (even if minor).
But once again, it was handheld, so regular use with camera body regulating it and not held so closely and not focusing on it in the night should be fine...


Mt Spokane Photography said:


> Jules said:
> 
> 
> > Answer is plain and easy : yes, it can ! And I know the effects firsthand :-(
> ...


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