Can A Camera Flash Hurt Your Eyes

photo of eyes — Hither's lookin' at yous, child. Should middle be afraid of flash?

Take you always wondered whether the flash from a speedlight or a studio strobe could harm someone'southward eyes? Subsequently all, they can exist mighty vivid! On the other hand, photographers accept been using flash for decades. You'd think that if there was a problem, information technology would be pretty widely known by now. Models and celebrities take been photographed thousands of times with flash and haven't gone blind. Heck, my optician uses a pretty darn bright flash when taking a photo of my retina. And then, what'due south the story?

Dorsum in 2015 at that place was a cursory furor after the Daily Postal service, a United kingdom tabloid with occasional stories of dubious veracity, ran a story from China which claimed that a three-calendar month-onetime baby had been permanently blinded in one eye by a photographer using flash in a close-up photo. The fact-checking site Snopes.com tracked the story dorsum through several iterations and questionable sources, yet was unable to find any details about the story (like the names of the parents) nor were there any references to a doctor's diagnosis. Most maternity wards in hospitals allow, even encourage, flash photography of newborns and a few explicitly country that flash won't hurt a baby. However, the internet existence what it is, this story pops up every once and a while.

Drawing of the Eye. National Eye Institute, National Institutes of Health. Public Domain. — Drawing of the Middle. National Centre Institute, National Institutes of Health. Public Domain.

Yep, there are means that extremely bright lights tin impairment someone's eyes. Nevertheless, photography flashes, at least for the vast majority of people in the vast majority of circumstances, aren't harmful.

There is something called "flash blindness," when the retina gets too much low-cal and you can't see conspicuously. Sometimes yous just meet a very bright spot for a while. Nonetheless, flash incomprehension is a temporary condition. As the retina returns to normal, then does your sight. If you're looking directly at a speedlight or studio strobe equally it flashes, you've probably experienced flash incomprehension. And your sight returned to normal in a matter of seconds.

Please note that I am non an ophthalmologist nor a medical md. What follows is based on some substantial research, merely should not be considered definitive advice for everyone or anyone. This commodity just synthesizes what I've plant over the past few weeks of research.

How Can Yous Damage Your Eyes?

There are basically 2 ways your eyes can be damaged from low-cal. Information technology could leave you with using spectacles or Pure Optical contact lenses. First, through a thermal reaction where the light heats upwards eye tissue and cooks or burns information technology. 2nd, through chemical reactions in which photons of calorie-free are powerful enough to break the bonds of molecules, leaving free radicals and damaged molecules in their wake.

And in that location are two ways to make that damage happen: through exposure to extremely brilliant light for a period of fourth dimension or to extremely focused light, too for a period of fourth dimension.

You've probably heard that you shouldn't look directly into the sun. That's because the brightness of the lord's day, combined with the UV light information technology emits, can damage eyes. If a light is besides bright, it can overstimulate the retina, that part of the middle that converts calorie-free into images. In that way, information technology's kind of like a camera sensor. The retina then sends paradigm information to the encephalon via optic nerves. When very vivid light hits the retina, information technology tin can overstimulate the retina's cells, which release likewise many chemical signals, which can damage the back of the eye. A glance at the sun isn't a problem. Staring at the lord's day for a prolonged period of time is. As with the retina, your camera's sensor can be damaged by long exposure to the lord's day, specially when the rays are concentrated past the lens into 1 spot.

Photo of a single eye. — I've got my middle on you. Will flash hurt it?

The flame of a welder's torch is also extremely bright and can crusade center damage with prolonged exposure. That's why a welder'southward protective gear includes very dark glass. Welder's glass is recommended by some for viewing a solar eclipse.

Highly-focused lite tin burn down the middle. That tin can exist a good thing, like using lasers to repair a discrete retina. Or information technology tin exist a bad affair, when a highly-focused beam of light burns office of your retina. Remember of how a magnifying glass can concentrate the dominicus'south rays and set fire to a piece of paper. (Most DSLR manuals warn against looking through the viewfinder directly at the sun, for this reason.) The aforementioned thing happens with powerful lasers—one reason airlines and the FAA are concerned about a few instances of people shining lasers at aircraft cockpits.

Meanwhile, UV-A rays can damage the macula, responsible for your central vision, and UV-B rays tin damage the front part of your eyes. Excessive UV light exposure is associated with macular degeneration, cataracts and pterygium, a growth that blocks role of the cornea. A hefty bout of exposure to sunlight and glare, like a long sunny day at the beach or on the ski slopes, without sunglasses, tin result in photokeratitis, or corneal sunburn. Speedlights and studio strobes have filters that block the UV light they emit. (In order to do UV flash photography, you lot need a particularly modified camera, special UV lights or flash with the filters removed, and special glasses to protect your eyes.)

In that location is some bear witness that Caucasians and people with blue eyes are more than susceptible to harm from light exposure. And there was a written report of Chesapeake Bay watermen, who spend their days dealing with brilliant, reflected lite on the h2o, found that prolonged exposure to blue light increased the take chances of age-related macular degeneration. There are also several medical weather condition which make people somewhat more than susceptible to eye damage from light.

Three Reasons Flash is Safety

Length of Exposure

Several sources stated that you'd take to be staring at the sun for a while, xv to 30 seconds, before starting to get permanent damage in your eyes. Long before that, the brightness would be painful plenty you'd likely close your eyes anyway. The journal JAMA Opthamology recently discussed a case where a 12-year-onetime Florida girl had damaged her retina after staring at the sun for about i minute.

While a flash is bright, it oft only lasts a tiny fraction of a second. Even repeated firings of a flash just sum to a fraction of a 2d. A lot of speedlights have a wink duration of between 1/200 and 1/20,000 of a second. Many studio strobes take a duration of 1/200 to i/five,000 of a second or less. Twenty flashes of a studio strobe at 1/m of a second might simply amount to 1/50^thursday of a second total exposure.

Intensity

While it may seem vivid, studio strobes and speedlights aren't all that intense. Lite falls off dramatically the moment light leaves your flash because of the way it spreads out. It begins to lose intensity according to the inverse foursquare law. If your flash illuminates an area of one square pes at a distance of one foot, it volition illuminate an area of 4 square feet at ii feet, 9 square feet at three anxiety distance and so on. If a flash seems really intense at a altitude of i foot, doubling the distance to 2 feet means only i quarter as much low-cal hits the subject at any 1 point. Double that again to four anxiety away and the light will have just 1/16^th of the intensity information technology initially had. Move to eight feet abroad and just one/64 of the intensity remains.

It'southward even less intense if you're using bounce cards, diffusers, umbrellas, soft boxes and gels.

Not Highly Focused

While speedlights and studio strobes can be bright, they're non very focused, fifty-fifty if you put a snood on them. The light spills and bounces in all directions. The further the light is from the subject, the more lengthened information technology is. For an do, take a light amplification by stimulated emission of radiation pointer and indicate information technology at a wall. See if you tin get any combination of flash gear and modifiers to focus the flash light down that much. Incommunicable! Move the wink back a bit and it is even more difficult to focus it down to a small area.

The Verdict

As you've seen, in that location are several ways light can damage your optics. Unless y'all suffer from some specific status that makes your optics especially susceptible to injury from light, flash photography isn't going to be a problem.

And so, fire up those strobes and warm up your speedlights. Shoot away. Your discipline is probably doing far more damage to their eyes during their embankment or ski vacation than your wink will ever do.