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This could very well be the most efficient, as well as costly, way of triggering off-camera flashes. Most professionals and serious amateurs would be using this system. How does it work? A trigger, which is connected to your camera and the flashes, are connected to receivers that pick up radio signals emitted by the trigger or transmitter on your camera when the shutter button is pressed. There several options available in this category ranging from cheap options for amateurs, like the
Cactus Wireless Triggering system or the Pocket Wizard. The higher end devices in this category can perform some advance functions like splitting several flashes into channels so that each can be controlled in a group, can be switched on and off wirelessly, etc.

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