What is a trigger?

An infra-red, radio or wireless trigger is a wireless set, consisting of a transmitter and receiver, with which the communication between a flash and camera is realized. When working with separate studio-flashes, you must be able to control these remotely in order to be able to adjust the moment of flashing and photographing to each other properly. The great advantage to using a trigger is that it can control several light sources, as a result of which you can light the subject of the photo exactly as you want it.

Communication between transmitter and receiver

As standard, a synchro cable is supplied with a studio-flash for realizing the contact between the camera and the flash. A great disadvantage is that with this option there is a wire hanging between the camera and flash and this could lead to accidents, certainly with studio photography with changing light. In this situation, it is more useful to purchase a wireless trigger set, with which the communication between transmitter and receiver is wireless. The transmitter is attached to the top of the camera and receives a signal when a photo is taken. This signal is picked up by the receiver. The receiver is located next to the studio-flash and is connected via a short wire. A reporter flash can then be attached on top of the receiver. The receiver reacts to the infrared or radio signal from the transmitter and sends a signal to the flash to give one or more flashes with the power settings. The signal strength can be configured in order to use several triggers at the same time. It is important when purchasing a trigger to carefully consider the maximum range, sometimes this is 10 metres and in other cases as much as 50 metres. Of course, the choice is completely dependent on the distance between the camera and flash(s).

Flash and camera settings

With a transmitter and receiver alone, the entire scenario of photographing using a trigger is still not complete. Because it is important to adjust the settings on the flash and camera in such a way that the desired light strength falls on the subject. It is important to set to work with the manual camera operation. For portrait or product photography in the studio, always assume an aperture of at least f/7 to have sufficient depth of field available. The ISO value can be set at 100 and during testing adjusted downwards or upwards. The shutter speed for flashing is between 1/125s and 1/200s. With a grey card and light meter, all these settings can be further improved.  

Use with several flashes and receivers

The advantage of a trigger set is that with a single transmitter and receiver several flashes can be operated. A flash is connected via the method discussed and will react to the signal from the transmitter. For other flashes, the slave function is engaged so that they can react immediately to the flash lighting from the first studio-flash. Since they can only give a flash in a fraction of a second, the delay is barely noticeable. Another possibility is to connect extra receivers to the trigger set and to therefore operate several flashes. This can be important in cases where there is no slave function, as well as when too much light enters the studio and as a result the flashes cannot react to each other.

Advantages of a TTL trigger

Just as with flashes, there are triggers available which support TTL. This stands for Through the Lens and is a lighting system with which the flash can be automatically provided with the correct power. The system can also respond well to the circumstances and the settings of the accompanying camera.