Adding multiple flashes to your outfit can dramatically improve the quality of your photos. The creation of master and slave flash systems allows for unusual creative ideas and illumination of large objects.
Separating flash units into master and slave
The master flash can be any device that can give a bright impulse - an external or built-in flash, as well as an infrared trigger. The impulse of the starter differs from the usual flash in its spectrum, it is not visible to the human eye.
Modern flashes have a special light trap on their body that gives a command to fire. Such traps can be found both on expensive top-end models from leading manufacturers and on the cheapest devices. They are even on flashes, made in the form of a light bulb, which is screwed into a standard cartridge and operates on a 220 V network.
Using light traps, flashes can be divided into master and slave. As a rule, the flash built into the camera is designated as the slave, and the others - as the slaves. The main condition is that the master flash unit must operate in manual mode. The slave device can be controlled in several ways - infrared, optical or radio. Newer cameras and large studio flashes support all three modes at the same time, and they can also be operated using a sync cable.
Multiple flash systems
If you line up several flashes, located at a certain distance from each other, in one line, then each of them will catch the impulse of the previous one and ignite from it. By its own impulse, it causes other devices to fire.
This system works due to the fact that the duration of the pulse of most flashes is 1/1000 of a second, while when shooting they work at slower shutter speeds - from 1/30 to 1/200 of a second. Each flash of this system has enough time to fire, it will still hit the shutter speed of the camera and its light will be registered in the frame.
Wireless flashes
Wireless flashes can be placed anywhere, however there are some limitations due to the principle of their operation. Infrared and optical systems must work within line of sight, especially when they are outdoors, and where there are no surfaces from which the signal can be reflected. One of the limiting factors is distance, with optical and infrared systems the signal will be too weak at a distance of 18 meters. Radio systems do not have this drawback, but their price is much higher.
