Wondering why you should use back button focus?

Back button focus usually confuses photographers at first but once they “get it”, they love it! If there is anything I wish I had known sooner in my journey as a photographer, it would be this one simple thing: Back Button Focus. This has been quite possibly the biggest game changer in my photography journey. Since I made this simple switch, I have noticed a remarkable difference in the accuracy of my focus.

BBF Photo 1

What is Back Button Focus?

Within your camera’s menu settings, you have the ability to assign certain functions to different buttons on your camera. Most DSLR cameras, by default, set focus by pressing the shutter button halfway down. This article is intended to explain the benefits of assigning the task of focusing to a button other than the shutter button. Back button focus simply changes the method of focusing by assigning the focus function to another button on the back of your camera (this button will differ depending on your camera model). This means that your index finger is now solely responsible for releasing the shutter, and your thumb is now responsible for focus.

And while many would argue that this makes it more complicated, I would have to disagree. While at first it may be different than you are used to, using your thumb and index finger simultaneously is certainly no more complex. Simultaneous use of fingers is something we do all the time in everyday life!

Before we get started, I’d like to explain that there is nothing “magical” about Back Button Focus. However, there are many situations in which utilizing the methods below will make better use of your camera and it’s capabilities. A lot of times, we just don’t know what those capabilities are. This article & video below is intended to help explain some of these capabilities, enabling you to have a higher degree of focusing accuracy in your photos.

Why use it?

There are a few reasons why I prefer to use Back Button Focus over focusing with the shutter button.

1. Your Focus will Hold (even if you release the shutter button).

When you remove the focusing function from the shutter button, you no longer need to worry about holding your shutter button down to maintain focus on your subject. How many times have you focus a shot, accidentally removed your finger from the shutter, only to have the camera refocus (and usually not on your intended subject) once you pressed the shutter down again? Using the shutter button to obtain focus requires that you continually find that perfect pressure balance of holding the shutter halfway down without 1) releasing the button and losing focus entirely, or 2) pressing the button too firmly and taking the shot before you were ready. Placing the focusing function on another button entirely allows the shutter button to only be responsible for releasing the shutter.

This may not seem like much of a game changer, but think for a moment about photographing a moving subject (sports or family and child photographers, anyone?). In the millisecond it can take to set focus and then release your shutter, your subject may have moved. The result: a blurry and out of focus subject. By separating the focus and shutter functions, you can set focus and get the shot simultaneously.  Gaining back those precious milliseconds via back button focusing allowed me to nail focus and get this shot as the family jumped from rock to rock.

BBF Photo 2

2. Focus & Recompose with Ease

Additionally, when you remove the focusing function from the shutter button, you enable yourself to focus the shot and then recompose the shot as needed, while your subject stays in focus. When the shutter button controls your focus, as soon as you recompose the shot and press the shutter, the camera will attempt to refocus again, leaving your intended subject out of focus. Sure, you could bypass this by locking focus, then switching your lens into manual focus, but what a hassle.

Some would say that focusing and recomposing should be avoided, and that you should just toggle your focus points. I agree, and I toggle my focus points in all situations. However, I also remember how few focus points some cameras have, and sometimes the area of focus falls outside of those points. Being able to recompose in those situations is key.

For more on recomposing your shots while using back button focus, be sure to scroll down and check out the graphic below!

3. More Versatile Focusing

What I really love about Back Button Focusing is the ability to pair it with a continuous focus mode for accurate and quick focusing in all situations.

Back button focus alone is beneficial, but if you frequently photograph moving subjects, you can really take your ability to nail focus up a notch by utilizing a continuous focus mode along with back button focus. A continuous focus mode (AI Servo for Canon, AF-C for Nikon) allows you to track a moving subject and keep it in focus. By continuing to press the focus button, your camera will automatically readjust focus as your subject moves. This series of images below is a perfect example. These were shot using the AI-Servo continuous focus mode, and back button focus. As my son was swinging the bat, I was able to maintain focus on him (even while he was moving) and take a series of shots in quick succession. I was able to do this because 1) the shutter was not trying to regain focus for each shot, and 2) my continuous focus mode allowed me to track his movement.

back button focus

In the photo below, I was able to track the movement of my daughter running towards me by keeping my thumb on the focus button as I released the shutter with my index finger. Even though she was running towards me and the plane of focus was changing by the millisecond, by utilizing back button focus and the continuous focus mode together, I was able to achieve excellent focus on an otherwise difficult shot.

BBF Photo 3

Can you use a continuous focus mode with the shutter button as your focus button? Absolutely. But, you forgo the above other benefits and the flexibility they afford you in all situations. This is why I love pairing Back Button Focus and a continuous focus mode—no matter what situation I find myself in, I have the ability to nail focus quickly and accurately. If I have a moving subject, I can hold down my focus button to track my subject and release the shutter at anytime. If my subject is still, I can lock focus with my focus button, recompose if I need or desire, and press the shutter to get the shot at any time. It truly is a versatile set up.

back button focus

How to Set Back Button Focus

If you use a Canon:

Setting your camera to back button focus isn’t difficult, if you know where to go. I will explain how I set it on my Canon 6D, and the process should be similar for other Canon DSLR cameras.

Please note, every camera model is slightly different, you might have to consult your manual or google for how to set back button focus up on your specific model.

Step 1: In my Canon 6D, the settings can be found in Custom Function III (C.FnIII),
Step 2: Scroll to screen 5 for custom controls.
Step 3: In that menu, I set the shutter button to “metering start.” (Turning if OFF of AF Start is what removes the focus function from the shutter, and this is a crucial step!!)
Step 4: Set the AF-ON button to “metering and AF start.”

Look to the photos below for help with these settings.

How to Set Back Button Focus Canon
how to set back button focus canon mark iii

Custom Controls Menu for Canon 5D Mark III – the rest of the steps are the same as on the Canon 6D as outlined above.

If you use a Nikon:

First check to see if your camera has an AF-On button. If you do, then it’s quite easy to set up back-button focus! The photos below are from a Nikon D800.

Step 1: All you’d have to do is select your custom settings menu (pencil icon)
Step 2: Select “a – Autofocus”
Step 3: Select “a4 – AF activation” and
Step 4: Select “AF-ON only” and you’re done.

How to Set Back Button Focus Nikon

If your Nikon doesn’t have a AF-ON button, you’ll need to set up the AE/AF-lock button in the custom menus to use it as the AF-On button. Do this:

Go to Custom Settings menu and then the Controls section. Choose Assign AE-L/AF-L button and scroll down to AF-On. Press OK and then the AE-L/AF-L button at the back of the camera now acts like an AF-On button for back button focusing.

How to Set Continuous Focus Mode

6_BBF Canon6D AI Servo

The continuous focus mode for Canon is AI Servo (for Nikon it’s AF-C) To set this on my Canon 6D I press the AF button on the top of my camera, and use the top dial to scroll to AI Servo.

Note: If you typically photograph still subjects or are a landscape photographer, back button focus and a continuous focus mode may not make much of a difference for you. Separating the functions of focus and being able to track your subject proves to be most beneficial for those who photograph moving subjects.

Back Button Focus is a great tool that has a lot of benefits. Some would even say it feel more natural and intuitive. But is it for everyone? Not necessarily! If you have a focusing method that already works for you, and don’t have issues with accurate focus, by all means, do what works for you.

Now it’s your turn! Are you already using back button focus? I’d love to hear what kind of changes have you noticed in your photos since making the switch! If you haven’t already made the switch, give it a try and let us know how you like it! It may take some time to get used to, but I think you’ll see a notable difference in your precision of focus!


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