WHAT ARE GROUPS AND CHANNELS IN PHOTOGRAPHY? Super-simply explained

Hello, fellow photographer! We've all been there, especially at the beginning of our journey, wondering how to connect our flash with the trigger so that everything works smoothly in the studio. All the settings can look so complicated! But don’t worry, I’ve got you covered.

I won’t delve too deeply into technical details, but I’ll explain the basics so you understand how triggers work with flashes and how you can pair them effectively. As I said above - super simply explained!

What are Channels and groups?

To pair a trigger with flashes, we need to set up their channels and groups. Both channels and groups allow us to connect the trigger to the flashlights and adjust their settings through the trigger. In the hierarchy, groups are located under channels.

Usually, you set all your flashes to the same channel but (in most cases) each flash is set to the different group.

One trigger won’t be able to work with different channels at the same time (i.e. if you have one flashlight set to channel 1 and the other set to channel 2, you won’t be able to fire them at the same time with your trigger), however, once all the flashes set to one channel - you can fire them all simultaneously.

Depending on your needs, you can either set all your flashes to the same group or each flashlight will be assigned to a different group.

Channels and groups explained

Channels

Why do you need multiple channels if you use just one? You might need different channels if, for example, you are in a photo studio with two different studios close to each other (like behind a wall). If you set your flashes to channel 1, and so does the other photographer in the studio behind the wall, you risk triggering each other’s flashes. To avoid this, you set flashlights in different studios (that are close to each other) to different channels.

Having said that, to each channel we can assign multiple groups, but each group is assigned only to one channel. Different channels can have the same groups, and they won’t interfere with each other.

When the photographer in studio 1 fires a flash, it won’t affect studio 2. However, if both are set to channel 1, then when the photographer in studio 1 fires the flash, it will also trigger the flash in studio 2.

Groups

Groups are helpful when you want to shoot with more than one flashlight and adjust their power separately.

Let’s say you want your key light to be more powerful than your fill light. In this case, you set your key light to one group (e.g., A) and the fill light to another group (e.g., B). This will allow you to adjust the key light’s power without affecting the fill light’s power settings. If you set both lights to the same group, their power will always align, which is not always useful.

On the example below, on the left I’d set each light to different group, to make sure I can easily adjust keylight’s power without affecting backlight, or vice versa. This way, I can set keylight e.g. to power 5 and my fill-light to power 2 and adjust them separately.

On the right, I can set both flashes to the same group, as I need them to be equally powerful (as long as both flashes are identical), to ensure my background is nicely lit without any gradients.

Note: If you set two different flashes (e.g., one is 500W and the other 400W) to the same settings, they will provide different results, as a 500W flash on power setting 5 will be more powerful than a 400W flash on the same power setting. In this case, I’d recommend setting them to different groups and adjusting them separately to equalise their light power.

Channels and groups explained

 To summarise...

• Channels help us avoid affecting (or being affected by) other photographers shooting nearby with flashlights.

• Ensure all your flashes and your trigger are set to the same channel.

• Groups allow us to control each light source separately. With groups and trigger manipulation, you can activate/deactivate lights, adjust their power, turn on/off modeling lights, etc., without directly interacting with the flashlight heads themselves.