Some of the cameras in Nikon’s Z mirrorless range have a dedicated AF-ON button on the back that is preprogrammed for back-button focus. In keeping with its minimalist and retro aesthetic, Nikon Zf doesn’t have that button.
But it does have an AE-L/AF-L button. By default, it’s assigned the role indicated on its label: locking auto exposure and autofocus. But you can repurpose that button for AF-ON.
It’s a two-step process. Here’s how to do it.
Back button focus assigns the camera’s focus function to a button on the back of the camera so that it’s separate from the shutter release button. This allows you to control focusing independently from taking the picture, which gives more control and flexibility for framing the shot. It’s particularly useful in genres like sports and wildlife photography, where maintaining focus on moving subjects is crucial, but I find it useful for any shooting situation, and it’s one of the first things I set up with a new camera.
Table of Contents
Step 1: Enable AF-ON Focus ONLY
By default, the Nikon Zf can autofocus two ways: by half-pressing the shutter and by using the AF-ON button (assigned by default to a lens button, if that’s available on that particular lens).
But you can disable the autofocus job from the shutter button. Like many photographers, I much prefer to have them separate, and find autofocus from the shutter button to be a real inconvenience when reframing the shot.
So the first step here is to disable the autofocus roll of the shutter button. To do that, go to:
Custom Settings Menu (pencil icon) > a Focus > a6 AF Activation
By default, it’s set to
Shutter/AF-ON, which displays on the screen as
To disable the shutter button functionality for focus, change that setting to
When you go back a level of the menu, the
a6 AF activation option will now show as
Step 2: Reassign the AF-ON Button to the AE-L/AF-L Button
That’s the first part done. The next step is to reassign the function of the AE-L/AF-L button. To do that, we use the Custom Controls.
Drill down to:
Custom Settings Menu (pencil icon) > f Controls > f2 Custom controls (shooting)
Then you want to click right to the AE-L/AF-L button. You’ll also see it highlighted in yellow in the camera diagram at left.
OK on that, and then scroll up on the menu until you get to
Select that, and back out by pressing the MENU button.
But What If You Want the AE-L Function?
Doing this, of course, will mean that the AE-L/AF-L button will no longer work for locking the exposure.
But being able to lock the exposure can be useful in lots of different shooting scenarios. And obvious example would be taking the exposure of a subject’s face and then wanting to lock that as you reframe the photo. Without exposure lock, the camera might recalculate the exposure based on the background or some other element in the frame.
I don’t tend to use the AE-L function all that much, but it’s still useful to have available. So what I’ve done is to reassign the front button on the camera, which is easily reached with the right-hand fingers when shooting. You could, of course, choose just about any other control on the camera–that’s the beauty of the ability to customize the functionality of the camera’s controls and buttons (and the lens’s, if you have a lens with a Fn button and/or a customizable utility ring.)
An Alternative Approach
There is, of course, an alternative approach that uses a different technique to get a similar outcome but does so without reassigning controls.
And that is to keep the existing functions as is and use them as a back-button focus lock override rather than as a back-button focus.
What I mean is that you can still use the shutter button half-press to focus, then lock that focus point in place with the AE-L/AF-L button, reframe the photo while still holding the AE-L/AF-L button, and press the shutter as normal. So long as you haven’t released the AE-L/AF-L button, the shutter button won’t refocus.