The Digital Photography Book

What Flash “Groups” and “Channels” Are For

Say you’ve set up three flashes—one is lighting your subject, the second is a hair light, and the third is lighting the background. If you increase the brightness, using your wireless controller (sitting on top of your camera), all three flashes will increase. You turn one up, they all go up. Turn one off, they all go off. If you wanted to control each one separately, you’d assign each to a different group. Most wireless controllers have three groups (some have four), usually named A, B, and C. I like to assign a flash to a group based on what it does. So, I always assign the main flash that lights my ...