I’m primarily a Canon shooter myself and I recently wrote a tutorial about how to set up a Canon camera for back button focus with two different buttons, where each button initiates a different focus mode. It’s a technique that’s not that well known, but I absolutely love using it. I wasn’t sure if Nikon cameras has similar functionality but I borrowed one from my friends at B&H Photo to take a look, and sure enough, you can also set up some Nikon cameras in much the same way.
Firstly, if you’re not familiar with the general benefits of back button focus then I would urge you to read my popular article: The Ultimate Guide to Back Button Focus. This details many reasons why professional and advanced amateurs gravitate to using this focus method. That same post also has details on how to set up standard single back button focus on Nikon cameras, so it’s a good place to start if this concept is new to you. If you’re comfortable with using back button focus though, it might be time to add even more functionality, and that’s what I’m going to talk about in this post.
What Exactly Are We Setting Up Here?
With regular back button focus the AF-On button activates the currently selected autofocus mode with the currently selected set of AF points. In this tutorial I will show you how to use two different buttons to activate two totally different sets of autofocus points. There are many combinations of AF settings that can be applied to these buttons, but in general most people will probably want to set up one button for single point AF and the second button for a dynamic group of AF points. This means you can switch back and forth between single point AF and an AF grouping just by moving your thumb to a different button.
An example of when this might be useful would be photographing an owl that is perched on a post. With the own sat still you would use a single AF point to make sure you are getting your focus in the right place to get nice sharp eyes. When the owl raises its wings to take off though, you can shift your thumb to the dynamic AF button which will be much easier to use when tracking an erratic and fast moving bird.
Can Your Nikon Camera Use This Focus Method?
Setting up any kind of back button focus requires the ability to customize the function of at least one or two buttons on the back of the camera. Some lower end DSLR models don’t offer this option, but if you’re using a mid range DSLR or higher, it shouldn’t be a problem. Double back button focus is certainly an option on the D500, D850 and the D5 but I can’t be certain about earlier cameras. Thankfully manufacturers seem to be more aware that people like the option to customize things, so I think these features will most likely trickle down to lower models in the coming years. If you aren’t sure if your camera can do it, the easiest thing is just to try and follow along using your camera menu. I think it’ll be pretty obvious when an option I mention in the list of steps, isn’t available in your menu. Since the technique we’re talking about doesn’t really have an official name (double back button focus is something I came up with), it’s not really possible to just search the user manual.
How to Set Up Double Back Button AF
Note that the screenshots in this tutorial come from a Nikon D500. It’s possible that the order of menu items and menu style might differ for your camera.
Part 1 – First Button – AF-On
You have a couple of choices here. Firstly, you can set the AF-On button so that it activates the currently chosen AF settings. This means that you still have control over things and can quickly change them if you need to. The second option is that you set it up to activate a specific set of AF settings, which is what I’m going to do because I think it’s a better demonstration of the adaptability of these buttons and settings. Once you’ve read though this, you’ll have the knowledge and understanding to choose whichever option makes the most sense to you.
Select Custom Setting menu (red pencil icon).
Select (a) Autofocus from the top of the menu, then scroll down to (a8) AF Activation. You’ll notice that in the screenshot above there is an asterisk above the a, which means that a setting in this section has been changed from the default setting. When you first encounter this menu, the default is for AF activation to be ON.
Select a8 and then select AF-ON Only. Press right on your 8-way controller to open the sub-section, and change Out-of-focus release to Enable. Once you then return to the (a) Autofocus menu, you will now see that a8 AF Activation is set to OFF. Frankly, the chosen terminology for this part of the setup process is awful, and it’s easy to get confused as to what is going on here. Essentially, this is where you are removing the AF function from the shutter button so that a half press of the shutter button no longer triggers AF activation.
Next you need to head back to the custom setting menu and choose (f) Controls, and then (f1) Custom Control Assignment.
In this menu we get to specify the function of many of the camera’s buttons. By default, the majority of Nikon cameras that have an AF-ON button have it set to AF-ON in this menu already, just like in the photo above. This means that when you press the AF-ON button, the currently chosen AF settings will be activated. For this tutorial we are going to make a change though, so go ahead and select the AF-ON button in this menu.
This next menu is where things start to get interesting! Even though the button is called (and labelled) AF-ON, you can actually choose from a plethora of different functions. The third option is the one we are most interested in so move your selector down to that one.
In this menu you can see that you’re able to choose the type of autofocus function that is activated by the press of the AF-ON button. For this example I’m going to choose Single-Point AF, but the choice is yours.
Part 2 – Second Button
Basically the process is going to be repeated for this second button, except that this time you’ll choose a different focus area mode. Exactly which button you choose for the second button is again, up to you. Nikon generously gives you several options on most cameras, including function (fn) buttons, and the depth of field preview button on the front of the camera. For this example, I’m choosing to use the sub selector centre because it is closest to the AF-ON button which makes it faster to switch my thumb from one to the other. You can see that I chose Dynamic 153-point or d153.
That’s it! With these settings, you can press the AF-ON button to use single-point AF, and a press of the sub selector button to activate d153 focussing. One thing that’s worth noting is that the AF Mode (AF-C continuous, AF-S single shot) isn’t affected by these buttons. So you still need to choose that, and then the two AF-ON buttons you’ve setup will just activate whichever mode is currently selected. The vast majority of people will want to simply select AF-C and leave it there though, because AF-S is somewhat redundant when you use any kind of back button focus. Simple press the AF-ON button quickly to focus, then release it, and you’ve basically got a single shot mode right there anyway.
Want to Take It Further?
If you don’t need to use the customizable buttons for anything else, you could even assign a third set of AF settings such as Group-Area AF to one of the buttons on the front of the camera, such as DOF preview button of Fn1. Be careful not to make things too complicated for yourself though!