Now, we come to the high end stuff – radio triggers. For what it’s worth, this is what I use day in and day out when I’m shooting with flash. These devices consist of 2 parts – a radio transmitter, and a radio receiver. The transmitter is attached to the camera, and the receiver is then plugged into the flash unit. You can buy generic triggers, such as these, which can then be plugged into pretty much any camera or flash unit, simply by using standard PC cables, or you can use a unit dedicated to your brand of flash like this one. In the case of the branded units, the receivers are generally built into the flash units – providing you buy one that is part of the system.
They have several advantages. First off, obviously, they’re not cabled in any way, so you can place lights pretty much wherever you choose. With no real need for line of sight, you can even position lights behind things, or in another room. I’ve triggered flashes from hundreds of meters away with these sort of things.
Dedicated units, like this Profoto system, will allow a great deal of communication between the transmitter and the flashes. This can not only allow you to know when they’re ready to fire, but can allow you to control power outputs, turn modelling lights on and off, and even use things like TTL mode.
Triggers can generally be set to different channels, and flash units to match. This serves 2 purposes – it permits you to create quite clever and complex set ups – you can have a whole lighting rig that’s very “soft” on channel one, and then a 2nd set of lights on channel 2 that’s very “hard”, and to switch between them all you need to do is press a button on the transmitter, rather than walk round each unit. Different channels are also vital if you’re working around other photographers with the same triggers. Channel 1 on my Calumet triggers will set off all the lights on any Calumet trigger within range on channel 1, even if they belong to someone else! Setting different channels avoids this.
The downsides are that obviously, they’re a bit more expensive, although not as much as you think – these Calumet ones are about £50 for a set, although they don’t offer the same degree of control that this dedicated Profoto one does. All radio triggers are also vulnerable to interference from other parts of the electromagnetic spectrum – so phones, broadcast equipment and so on, may interfere with your signal.
You can probably guess – I’m quite a fan. I switched to using radio triggers about 15 years ago, and haven’t looked back. Dedicated ones like the Profoto one are fantastic, but if you’re just starting out, even a simple system like these Calumet ones are well worth the money. You’ll be so grateful when you’re able to trigger a light you’ve placed in a remote location, and don’t have to trip over cables, or better yet, turn the power up or down on a light that’s rigged up in the rafters where you can’t reach
Light-based control systems
The final type of triggering I want to talk about is specific to camera manufacturers – Nikon call it CLS, and Canon have a similar system too. I think other camera makers have something like this, but you’ll need to check. It’s essentially just like a radio trigger, except that it uses pulses of light from a “master” flash to control the output of other “slave” flashes. It gives you all of that control, and allows you to create groups and channels, and all of this without wires.
The catch is that, being optical, it needs line of sight. You can get away with a little bit of hiding indoors, as walls and the like will reflect the light signals, but outside, particularly on a bright sunny day, it’s range is very limited. It also only works with specific flash guns – whichever ones you want to use must all have this system, you can’t mix and match. Since it works by sending out a pulse of light in advance of the main flash, it also often precludes you from using a simple optical slave – the slave will see the pulse flash and fire it’s own flash – but it will be out of sync.
I’ve used it from time to time, and if you’re lucky enough to have several flashguns from the same brand, give it a go, it’s very handy in indoor situations. However, it’s limitations mean that I don’t rely on it much as a professional, and if you’re just starting out, I’d suggest investing your money in some inexpensive radio triggers instead. There are now systems out there, such as these pocket wizards, which allow systems like this to function over a radio signal, thereby removing a lot of the issues. The catch with this though, is the cost, as now you not only need to buy flashes that are part of the system, but a trigger of some sort for each flash!
Triggering – Conclusion
So, that’s how to trigger your flash. Sorry for going in to what seems like so much detail, but I’m very aware that if you’re just starting out it can be bewildering, and hopefully I’ve made things clear and simple enough. That wraps flash up for now, although we’ll be touching on it again a bit later when we talk about modifiers. Next, we’re going to look at continuous light.