Maximum flash power harmless for the model's eysight

[Andrey Vorobyov]

Hello,

there was a related topic about portraits in LF: http://greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=003TNA

One of the solutions is obviously to increase the flash power. Sometimes my models say their eyes become quickly tired when I use even VERY wea k flash. My question is: are there some common limit of flash power from point o f view of the healt? Are such limits individual?

Thanks

Andrey

[John H. Henderson]

I believe that eyes tire because of the pupil opening and closing in response to changing levels of light. This is why your eyes tire while driving at night - they are constantly trying to readjust to the headlights of oncoming traffic and to passing lights.

I doubt that most commercially-available flashes are going to cause any damage when used as intended. (e.g., you don't hold the bulb to your eye when you fire it.)

As for your situation, Andrey, are you in a studio? Are you turning modelling lights on and off? That may tire a model's eyes more quickly than the actual flash.

[Brian C. Miller]

Have you tried increasing the ambient light level in your studio? If the ambient light level is brighter, then there won't be as much a shock to the eye when the flashes are triggered.

I remember that when Kodak was making their large panoramas, they used multiple 9600ws heads, which vaporized the water in the surrounding air, letting off a puff of steam around them when they were fired. (Oh, yeah: the models were fine.)

[Andrey Vorobyov]

Thanks for the input, gentlemen.

Yes, I'm in studio. I don't turn the modelling light on/off, but the level of the ambient light was sometimes pretty low, so you are correct: it is the shock from quick changing light level. I avoided to increase the ambient light level fearing it can destroy the lighing pattern, but some simple measurements showed I can do it at certain degree without affecting the pattern. So thanks for the idea! I've forgotten to mention that the tired eyes simptom occurs only if the flash directed in the face -- a very uncomon situation in my work but, but in still takes place sometimes. So I'm just curious: e.g. flash with power f/90 (at 1 m ISO 100) are not uncommon, so how harmless is to use it if model eyes are accomodated (or not accomodated) to bright light? (The accomodation degree can be judged looking at model's eye pupil, for example). Personally I never heard about harm to eysight caused with flash light, I'm just trying to foresee (and prevent if necessary) a possible harm. Thanks

Andrey

[Altaf Shaikh]

f90? that's some serious flash power in someones face. What exactly are you trying to accomplish?

[Andrey Vorobyov]

Altaf, I do NOT intend to bounce f/90 into face of someone, and never will, hopefully. I only ask about limits.

Andrey

[Lloyd Chamber]

Flash at close range and/or at high power can damage the retina. Just put your hand over your flash and pop it--it gets pretty hot. A powerful flash could cause a burn.

So the question is the intensity of light reaching the eye.