The electronic device known as a trigger circuit is used by photographers to activate external and supplementary flash devices. The trigger is used to make sure external flash devices and the camera’s go off at the exact same moment.
When all of the flashes fire simultaneously it will produce clear and shadow less photos in situations where the harsh primary light will surround the subject in deep shadows. There are two typical trigger circuit types, the slave circuit and synchronized output circuit.
The best way to get rid of unwanted shadows is to utilize fill flashes and fill lighting to evenly illuminate the person or object. Natural and studio lighting techniques are easier to control as the light source is constantly on, but when using flash fills everything should be properly synchronized by using a trigger circuit.
The trigger circuit basically provides a circuit or connection between the trigger source and external flash. When you trigger the circuit the external flash will fire. The circuit is connected in a way that makes the camera the actual trigger source. The external units then go off when the camera’s flash fires.
Slave trigger circuits aren’t connected with your camera and external sensors provide the trigger source. Some types of slave trigger circuits fire the flashes and activate the camera’s shutter release by using a sound sensor.