How to Use External Flash on a Canon

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Canon offers a versatile range of cameras that allow you to capture aesthetic shots. Despite their features, using external flash gives you a lot more flexibility and the ability to capture better photos in low light conditions. Therefore, learning how to use an external flash on a Canon camera allows you to capture better photos.

How to Use an External Flash on a Canon Camera

To use an external flash with a Canon camera body, you need to first choose the right flash unit. After that, mount the unit and choose the shooting and the flash synchronization modes. After that set the ISO levels on your camera and you are good to go.

An image of external flash on Canon

Choose the Right Unit

First, choose the right unit. Canon cameras are compatible with flash units besides the Canon brand, which include Neewer, Meike, and Godox. You can connect these with either the hot shoe on the camera or connect it wirelessly.

Mount the Unit

Insert the flash unit onto the hot shoe at the top of your camera. Make sure that the it fits into your camera, otherwise it won’t fire. There are different attachments, so check if your camera’s hot shoe can fit the unit first.

Slide the mounting foot lever to lock it. Switch on the camera and make sure it is connected to the external flash by going into the menu and under external speedlite control flash firing is enabled.

Choose the Shooting Mode

Next, choose the right mode. The mode depends on the conditions you are shooting in and your preference.

For example, you can choose the TTL mode. The TTL or “through the lens” mode is an automatic mode which sets the flash settings according to the situation at hand. This mode is chosen when the conditions are changing and you do not have time to change the settings manually constantly.

Then there is a manual flash mode, which allows you to set each setting manually. This includes the flash output, that determines the intensity of the flash.

Another mode that you can choose are the slave modes. These modes allow you to establish a wireless connection with the unit. When the master flash fires, the unit goes off too.

Choose the Shutter Synchronization Mode

After selecting the shooting mode, pick the shutter synchronization mode. You have two main options: high speed sync and second-curtain sync. A high speed sync is a good idea when you plan to use a faster shutter speed. This makes sure that the flash fires according to the shutter speed.

The second-curtain speed is more suitable for long exposure shots. You can change this mode by holding down the flash button and moving the mode dial on your camera.

A close-up image of external flash

Set the ISO Levels

The ISO levels refer to the camera’s sensitivity to light. ISO level allows you to capture photos in low light conditions. However, with a flash unit, you do not need high ISO levels. Therefore, adjust the ISO levels to a low level, since this will reduce the noise in your pictures.

Use the Flash Unit to Capture Photos

Once attached, you can use this unit to capture photos in various ways. One way you can use the flash is in low light conditions. These might include capturing photos at night as well as indoors. Besides that you can use the flash to illuminate the subject when the surroundings are bright.

Furthermore, you can diffuse the light coming from the flash unit. There is an in-built diffuser that can be used for this purpose or you can cover the flash with an opaque object. This reduces the intensity of the light and creates a nice effect.

Using Wireless Flash on Canon

Some Canon cameras allow you to use external flash units wirelessly. This means that you can fire a unit without it being attached to the camera. This gives you a lot more flexibility as it is not restricted by the position of the camera.

However, not all the Canon cameras support this. Some models that support wireless connection include 7D Mark II, 5D Mark IV, T5i, T4i, T3i, and 60D.

To use the flash unit wirelessly on your Canon camera, follow these steps:

  1. Turn on your camera and turn the mode dial (on the top of your camera) to one of the manual flash modes. The manual flash modes include PASM modes.
  2. Press the Q button which you will find on the back of your camera. Move around or look through the options until you find the flash icon. Press the “select” button.
  3. You will now be presented with three options: easy wireless flash, custom wireless flash, and normal wireless flash. Choose the easy wireless flash option. For some versions you will find this under flash control.
  4. Make a note of the channel your camera is using. By default this would be channel 1.
  5. Pop up the flash on your camera. This is very important and the wireless connection will not work if you skip this step. For cameras that do not have a pop up flash, you can set up a remote flash trigger. Here, one trigger is attached to the camera through the hot shoe, while the other is attached to the external flash. When you click the shutter, it sends a signal to the external flash to fire.
  6. On your flash unit choose the slave mode. On some models it can be done by switching on the physical switch. For others you will need to press and hold the zoom button to change modes.
  7. Change the flash unit’s channel to the same one as your camera. 
  8. Position your flash. When you fire your camera’s flash, the flash unit’s flash will fire too.

Advantages of Using External Flash on Canon

There are several advantages of using external flash on Canon. These include the following:

An image of external flash
  • Low Light: Using an external unit improves your ability to capture photos in low light conditions.
  • Diffusers: These units allow you to use diffusers that give light a lot more cleaner look. While you can use handheld diffusers with your camera’s in-built flash, it is a lot more convenient and better looking with external units.
  • Red Eye: These units allow you to reduce chances of red eye in photos. This is because the light is not coming from the center of the camera.
  • Better Illumination: They allow you to better illuminate objects at a high distance from your camera. These units are more powerful than your camera’s in-built flash.
  • Better Control: They give you a lot more control over the lighting of the situation. You can move the flash unit around to create shadows, highlights and a lot more effects than your camera’s in-built flash. This is thanks to the wireless connection ability.

Related Questions

Why Is My External Flash Not Working?

Your external flash might not be working because it is not inserted into the hot shoe of your camera correctly. Also, your connection cord might not have been connected to the camera the right way either. Moreover, there is a chance that the batteries have been drained or entered incorrectly.

Furthermore, the hot shoe on your camera might not be compatible with the type of external unit. In case of wireless connection, you might not have chosen the right channel.


You can use an external flash on your Canon camera by mounting the unit and choosing the various modes. Make sure that the camera is compatible with the unit in question. Some Canon cameras also allow you to use the unit wirelessly, therefore giving you a lot of flexibility.