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"burning" is a bit of an exaggeration, I think. It's just overstimulating your retina cells, so they sort of take a rest. It doesn't take much energy - glance a
by jonhendry 16y ago
"burning" is a bit of an exaggeration, I think. It's just overstimulating your retina cells, so they sort of take a rest. It doesn't take much energy - glance at a 40-watt unfrosted bulb, then close your eyes, and you'll see an afterimage.
- mansr 16y agoFrom the video it appears they are using 2 (or more) Pro-7b 1200 units, each delivering 1200 Joules of energy per flash. That's enough to light a 40-watt bulb for a full minute, and the lighting efficiency is considerably higher. BTW, the Pro-7b is a rather small battery-powered flash unit. The bigger mains-powered ones pack twice the energy (and have much shorter cycle times).
- brk 16y agoYes, but that energy was also mostly masked by the "BMW" stencil and then also apparently filtered through the projection screen. The amount of light actually hitting the viewers' eyes was much much less than the actual output of the strobe units.
- hardy263 16y agoYour 40-watt bulb has to be fairly close in proximity in order for the light to make things more visible. And since movie screens are so big, you have to be fairly far away in order to see the whole picture. The energy output from light follows the inverse-square law, so double the distance is 4 times less bright, and quadruple the distance is 16 times less bright. So although the energy output is higher, it's probably not as bad as you think it is.
- mansr 16y agoI never meant to imply it was bad. Looking directly at a flash bulb like that from typical movie-viewing distance is perfectly harmless. I would not want to look at one up close, however.