Back button focus is all the rage with both amateur and professional photographers alike. It essentially removes the auto focus function from the shutter button. By default, when the shutter button is pressed half way down on Canon cameras, the camera meters the scene, auto focuses the lens and chooses a white balance. If the shutter button is pressed down all the way, the photograph is captured. By changing a setting within the camera, it’s possible to strip the auto focus function from the shutter button and reassign it to a another button that’s located on the rear of the camera. To be more specific, it will assign it to the AE Lock button. This button is located in the upper right corner of the rear of the camera. It’s marked by an asterisk.
Once the change is made, to focus the camera, you’ll need to press the new back button. To take the photo, you’ll use the shutter button as you always have. For more on this topic, please visit my post on back button auto focus.
I’ll include the instructions below to change the settings for the Canon Rebel line of cameras as well as many other Canon cameras. These instructions may not be an exact fit for your camera, but I’m sure you can get things to work with a little fishing around in your settings menu.
1. Turn your camera on and press the MENU button on the back of it.
2. Inside the menu area, you’ll need to scroll to the left or to the right with the arrow keys until you land on the screen that contains the Custom Functions (C.Fn) menu item. Press the SET button to access that area.
3. Next, scroll to the left or to the right again until you reach the Shutter/AE Lock button screen.
4. Scroll down and change the highlighted option of 0. AF/AE Lock to 1. AE Lock/AF. Press SET to accept the change.
5. That’s it!
If you have any questions regarding these instructions, please ask below. Also, if you have anything else to add, you may post that below as well. Thanks!