Imagine you’ve just turned up at your all important shoot where you’ll be using flash. You have your flash guns, your light stands and modifiers. All you’ve forgotten is the wireless trigger! So you go home, everyone is sad, and the world ends the next day.
If only there were a way to fix it…
Well, there is, and it’s a simple one.
Your manual flash has various modes, one of which is called “slave” mode. What slave mode means is that the flash will trigger as soon as it sees another flash. In traditional flash photography, when using two lights, typically you set one to be triggered wirelessly, and any others can be set to slave mode and they will trigger when the first flash fires.
So set your flash to slave mode, and we’re going to trigger it with another flash. Your pop-up flash.
“Yuck”, you cry, “no one uses the pop-up flash, the light it creates is hard and flat.” True, but we’re going to dial it back until we can’t see it. Go into the camera’s menu (read the manual if you need to) and dial back the flash power to minimum. You may find it helpful to lower the flash exposure compensation to the lowest it will go. We don’t want the light from the pop-up flash to illuminate the scene, just to trigger our main flash.
So, I demonstrated this with a shot of the Canon AE-1. From the test shot with the slave flash switched off, you can see that the only light is a reflection in the lens from the flash.