Back button focus is just what it sounds like. Instead of using half-press on the shutter button to enable auto focus, hold a dedicated button on the camera's backside instead. When you release, the focus remains locked. This is why you may want to use it.
RELATED: How to Get the Most Out of Auto Focus with Your Camera
Advantages of Backward Focus
The great advantage of backward focus is that it differs from the Action to focus on taking pictures. The default camera setting where the shutter button controls both actions makes some things difficult, like trying to focus on a part of the scene that does not fall well below an autofocus point. It can also slow down the camera burst mode while the auto focus chases, which prevents you from taking pictures.
With Auto Focus Backward, you can easily focus on what scene you want in the scene and then reshape your shot without worrying about using any kind of AF lock. And because your focus will be locked until you change it, you can continue shooting without worrying about auto focus and try to focus on something else. This is very useful when your subject does not move too much.
Another great feature is that you do not need to choose between manual focus or individual and continuous auto focus modes. If you enable Back Button Focus and set the camera to continuous auto focus:
- To manually focus, do not press the focus button, but focus manually with the lens ring instead. Most pros and professional lenses let you focus manually, even though the lens is set to auto focus.
- To focus, hold down the focus button until the focus acquires a lock. Then release it and slide away.
- To continuously focus, hold down the focus button and continue firing.
As you can imagine, after hanging on things, it makes it much faster for you to respond to different situations. And as I have said time after time, it's not about not using the camera's automatic features. It's about using them in such a way that you control how they work. Autofocus on the back button is one of these ways.
Setting Back Button Focus
To set the Back Button Focus, you must dig in camera menus. You usually have to do two things:
- Remove autofocus from the shutter button.
- Set the AF-ON button – or if the camera does not have one, AE-L (* on Canon cameras) – can be used to enable auto focus.
For Canon cameras, dig in the menu until you find Custom Features. On consumer cameras, look for the option that sets the shutter button on AE Lock and the AE lock button to AF. On more advanced cameras you have more control over which buttons are working, so you can play until you have a setting that you like.
For Nikon cameras, find the Custom Settings menu (that's the pen icon) and go to the controls. Select Assign the AE-L / AF-L button and select AF-ON. Then go to autofocus and select AF activation. Just select AF-ON, and you're good to go.
If you have any issues or if the camera is not of any of these manufacturers, Google will display your camera's model and auto focus on the back button. Someone will almost certainly have a specific guide.
Backward focus is much more flexible. When you begin to check the basic exposure settings, it's worth playing with it and see if it's for you.