If you would prefer to use a back button to activate the autofocus on the Sony a7R IV instead of using the shutter button, then this short guide will explain how to set this up.
I’ve also created a short video guide showing how to do this but if you don’t like the sound of my voice, then just keep scrolling for the written steps.
Since I shoot a lot of sports and wildlife and I am probably shooting in AF-C mode 99% of the time, I prefer to use a back button to enable autofocus instead of half-pressing the shutter button.
Using this method I’m much less likely to fire the shutter accidentally and also when I remove my finger from the shutter button the focus will stay locked on so long as I have the back button pressed.
When using the shutter button to focus you’ll lift your finger off the shutter after shooting a burst but in doing so risk re-focusing and potentially losing track of your subject and missing shots, this isn’t an issue when using the back button focusing method.
To setup back button focusing on the a7R IV there are only two steps required.
Step 1. Turn Off Autofocus with Shutter
In the first step we want to remove the autofocus from the shutter button, so when pressed it will now only trigger the shutter and not the autofocus when half-pressed.
Hit the menu button on the back of the a7R IV and navigate to Camera Settings 1 > AF2 (6/15), then select the menu item [AF w / shutter] as shown below:
By default this is set to on, simply click the menu item and set this to off like shown below:
Step 2. AF-On Custom Button Setup
By default the Af-On button on the rear of the a7R IV is already setup to trigger the autofocus when pressed, so you shouldn’t need to follow these steps unless the function of this button has been changed. If it’s not working then here’s what you’ll need to do.
Hit the menu button on the back of the a7R IV and navigate to Camera Settings 2 > Custom Operation 1 (9/11) and select the first menu item [Custom Key] as shown below:
When you press the [Custom Key] menu item you should now see the following page:
Check that custom key number 3 is assigned to the “AF-On” function. Providing it is you can now exit out of the menu, if it’s assigned to another function then you’ll need to select the AF-ON function from page 7/27 as shown below:
Providing everything has gone to plan your shutter button should no longer be activating the autofocus when half-pressed, instead the AF-On button is now used to enable the autofocus when held down.