Radio trigger
A small radio unit normally mounted on the camera hot shoe. A small receiver unit is also mounted on the off-camera flash. The radio trigger saves having the camera and flash connected by long wires.
When the camera takes a shot the radio trigger will broadcast a signal. This trips the flash receiver unit. The receiver then fires the flash gun.
A radio trigger normally has more than one radio channel. Possibly as many as sixteen channels. This allows the user to change channels to prevent firing flash units of other users nearby. If a user takes a photo using the same channel as other nearby users the shot will fire the flash of both cameras. That might cause too much light to be output from two flash guns when only one was expected. It’s rude to fire other peoples flash guns. It is a battery drain and may spoil a shot they were going to take.
Each make and model of a radio trigger offers different functions. The more functions offered the higher the price. Branded models of radio trigger are often the most expensive. However, they offer a lot of control over the flash via the radio trigger. The most complex radio trigger will operate the flash as if in TTL mode (through the lens mode). Check your manual for details of the TTL mode functions.
The most basic model of radio trigger will only fire the flash when triggered. This leaves the user to manually set the flash intensity (power) in advance. A little experience is needed for this manual use. But, most learners can quickly and easily take a few test shots and gauge what flash power-setting to use. Read your manual on how to change the flash power level.
Please carefully check the specification for radio trigger units. Often units are designed for a small range of cameras. If you buy one that is not compatible you may damage your camera.
Photographic Glossary – Definitions, articles and resources…
Definition: Hot Shoe.
Definition: Off-camera flash; Flash, off-camera.
How to take a test shot
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