Brian in Whitby wrote:
Diodes, including the light emitting diodes, LEDs, only allow electrical current to pass through them in one direction. Since the lights are using 60 Hz AC, the electricity travels first in one direction and then I the opposite direction. This happens 60 times each second. The result is the LED switches off and on 60 times a second. At shutter speeds faster than 1/60 s, the photo is taken when one of the lights is off. The work around is to use a shutter speed of 1/30 s so you catch both lights on during the exposure.
There are ways of manufacturing LED light bulbs that do not behave this way by using a full wave rectified circuit to change the AC into DC. but it would increase the cost of the bulb and is probably not worth it for holiday lighting.
I wonder is the same thing happens with LEDs used for general lighting? The same thing would happen at least some of the time, the light would be off when you press the shutter.
Diodes, including the light emitting diodes, LEDs,... (
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Merci Brian.