How to Trigger an Off-Camera Flash with the Pop-up Flash

If you have ever wanted to explore off-camera flash but don’t know where to start, I have some good news. Many consumer-grade cameras such as the Canon Rebel series and the higher end Nikons like the D700, D300, D300S, D7000, and D90 (the D3x00 and D5X00 models do not offer this) models have a fantastic feature that might be just what you are looking for.
One challenge with off-camera flash is that you need a way to fire them at precisely the right moment. That usually means outfitting them with tiny little remote controls called triggers, that are tied into a transmitter unit affixed to the flash hot-shoe on your camera. When you want your off-camera flashes to activate, the transmitter sends a radio signal to them, and they go off at precisely the right time to give you the photo you want. Some triggers are inexpensive, while other, more customizable one,s will set you back hundreds of dollars. But, if you own one of the cheaper Canon or Nikon bodies, you already have a handy trigger built right in to your camera; the pop-up flash.
Several manufacturers have this feature built-in to their cameras, but since Canon and Nikon are the most popular, those are what I’m going to focus on in this article. Both types of cameras require you to change a few menu settings that may seem a bit confusing at first, but get easier with practice.
Setup for Nikon cameras
On a Nikon camera the first thing you will need to do is set your internal flash to Commander mode. This means it will still fire a burst of light when you take a picture, as a way of communicating with your external flashes. You will see this when you take a picture, but don’t worry, this brief burst is not bright enough to have much of an impact on your photo. This quick flash instead serves as a signal to your external speedlights that they need to fire. To do this, press your camera’s Menu button, then choose Custom Setting Menu (Bracketing/Flash) and the “Flash control for built-in flash” option.

The default value for the “Flash Control” option is “TTL,” which means that your built-in flash functions exactly how you normally expect, and has no control or interaction with any off-camera flashes. Change this value to “Commander mode” which will then allow you to use it to trigger external speedlights.

The final menu looks a bit complicated, but you only need to change a few settings in order to get everything set up initially. Change the Built-in flash option to display two dashes (–) and leave the rest of the values as shown below; Group A TTL, Group B TTL, and Channel 1.