Click Thumbnails to Enlarge
Correct positioning of flash

How does wireless flash work?

Techniques

28 October 2008 15:59

These days when we think ‘wireless’ we think of networks similar to those used for computers in the home or office. However, wireless flash simply refers to the fact that these are no wires, rather than relying on radio waves as your wireless network at home does. Instead, wireless flash uses light to transmit the signals and data between units.

The system relies on a master/commander unit (weather it’s your pop-up or additional on-camera flashgun), which sends out a series of tiny flashes that are too quick for our eyes to detect. These flashes are picked up by ‘slave’ units, which then communicate back to the master. The maser unit can then process all the data it receives to determine the amount of power needed. It does all this in the time between you pressing the shutter button and the picture being taken.

Learn the wireless basics
There are a few more terms you need to get to grips with before you can start experimenting with wireless.

Commander/Master unit
This is the unit that controls the wireless flash system. Some cameras allow you to use the pop-up flash as a commander but if yours doesn’t, you’ll need to buy either a flashgun with commander capability or a special commander unit in addition to your remote flash.

Remote/Slave unit
This refers to the flash or flashes positioned off-camera to be controlled by the commander unit. You can use just one, or several slave units, depending on how many you can buy, beg or borrow from friends. Each needs to be wireless-enabled and compatible with the system your using.

Channel
When setting up a wireless flash network, you need to select one of the 2-4 available channels offered by your commander unit. All remotes you intend to use need to be set to the same channel.

Group
Each channel is broken down into groups. This allows you to set the power differently for individual remote units so they don’t all deliver the same amount of flash. This allows you to set up a powerful main flash complemented by less powerful fill-flash.