Do your photos turn out to be out of focus? Or do you experience trouble with focus shifting when you press the shutter button? In this article, you will learn how to use back button focus on your camera. This will help you to nail focus where you want to and avoid a lot of focusing obstacles.
As a landscape and nature photographer, there’s nothing like being in the outdoors. So, when a fantastic moment unfolds before me, like a dolphin jumping out of the water or a fox puppy emerges from its hideout, I want to make sure I have the practice and knowledge to be able to capture the scene as it unfolds.
When I first started my photography journey, capturing a shot like this was impossible. I didn’t have the skill, technique or know-how of an experienced professional.
So, to capture a shot like the one above or any photo for that matter, I would recommend you learn about using the back focus button on your camera. If I had known about this mode when I was first starting, then I’m sure I could have possibly recorded many more shots like this one.
Hopefully, you have your camera in front of you so you too can back button focus mode on your camera. I’ll take you through the steps later in this article. You will be surprised at what a difference this new focus method can make!
What is Back-Button Focus?
To begin, we must first understand what back button focus is and then we will go into some of the benefits of why you should use the system.
Back button focus is an advanced way of locking your focus to a subject, without having to worry about what focus mode you are in. You can bypass having autofocus assigned to the top shutter button of your camera.
The advantage of doing this is you can take photos much faster than before. Simply put, the focus on the back button is the process of removing the autofocus function from the shutter button and replacing it on the rear of the camera.
The way back button focus operates is when you press the dedicated or assigned button, you will activate the ‘AF-C’ focus mode on your camera. In order words, this mode will keep acquiring focus as long as you have the button pressed down.
Simultaneously, all you have to do then is press the shutter button to take the photo. This is because once you have activated back button focus on your camera, the main shutter button won’t control the focus anymore.
Having to press two buttons (dedicated focus button + shutter button) to take a shot, seems more complicated at first thought, but it is the fact that a single button tries handle two different tasks that give you focus issues in the first place.
If you want to take the photo, you still have to press the top shutter button. The difference here is the top shutter button now doesn’t have to obtain focus every time you press the shutter button halfway down to take the shot.
This quicker way of doing things makes it faster to get your shot with a bit of practice. Additionally, with back button focus you can operate all your three focus modes in one, more on that later though.
Benefits of Back-Button Focus
So why all the fuss in changing the buttons for how your camera activates the autofocus? Well, I will get to that, but first, let’s get into more detail about the benefits of doing so.
Assigning the focus to the back of the camera is a technique that is used by experienced professional photographers so they can concentrate on the subject.
As a practical example, take this photo of a fox puppy. Notice the grass in front of the beautiful creature?
If I had used a traditional way of focusing, there’s no doubt the conventional camera’s focus system would have got it wrong. From experience, the focus algorithm would easily have narrowed in on the grass in front of the animal, instead of the eye of the fox.
The advantage of back button focusing, on the other hand, is that I could release or press the back focus button depending on whether I wanted to acquire focus again.
This left the shutter button to do what it does best – take the photo.
Now, if that’s not a big enough benefit for you, then what about when I mentioned the camera could operate all your three focus modes in one? That’s right; you can also operate manual focus in this mode without having to switch the camera’s manual focus switch physically.
Shoot in AF-C with the Benefits of AF-S
With back focus button set up on your camera, there’s no need to navigate to your focus switch. No more do you have to switch from AF-C to AF-S and back again.
If you are unsure what the difference between these two focus modes is, then let me explain.
AF-C (otherwise known as ‘Continuous’, ‘AI Servo’ or ‘C’) controls your focus continuously. Put in practice, when you hold the shutter button down the camera will continually focus on your moving subject.
AF-S (‘Still’ or ‘Single’) is dedicated for stationary objects that only require you to traditionally half-press the shutter button. Once focus is acquired it stops adjusting it. You can say that focus is locked once it is acquired in AF-S. To get the camera to focus again you need to half-press the shutter once more.
With back button focus in operation, these modes are operational all the time. All that differs is how you press the back button.
As long as you press and hold the back focus button, your camera will adjust the focus, like in AF-C mode.
When you release the back focus button, your camera will stop trying to acquire focus with the focus being locked to where it was when you released it. Just like in AF-S mode.
No More Refocusing Every Time You Let Go of the Shutter
Pressing the back focus button changes the way the focus system operates on your camera. With this advanced mode of using autofocus you now no longer have to refocus every time you let go of the shutter button.
The camera also stops trying to focus if you are a little hesitant with the shutter button. This can easily ruin a shot where you have first acquired focus and then recomposed to improve the composition. If you accidentally half-press instead of full-pressing the shutter button the focus will change and your shot is ruined.
Avoid Obstructions Getting In Focus
If you photograph wildlife, then I highly recommend you change to back button focusing. If you use the standard focus setting what can happen is the animal will move and instead of maintaining focus on the animal, the camera will refocus on a leaf in the foreground or a blade of grass.
Instant Manual Focus
With back button focus you can also focus manually whenever you want. You don’t even have to switch the autofocus system off on the camera either. Just use the manual focus ring on your lens.
This is a massive advantage for both macro and landscape photographers as sometimes you may have to micro adjust your focus because cameras won’t get it right all the time. Because the shutter button no longer tries to acquire focus, manual focus will not get overridden by the autofocus system when you press the shutter button.
What are the Downsides To Using Back-button Focus?
By using back button focus, you might find it a bit more complicated to use the camera at first. This is why for decades the camera manufactures has been using the semi-press shutter method for acquiring focus.
One downside of this system is it takes time to master and get your head around how the focus system works. But after you grasp how it works you don’t need to learn when to switch between AF-S and AF-C, or remembering to switch between autofocus and manual focus and so on. So a lot of things get simpler, after this slight bump on the road to mastering your camera fully.
However, you are likely going to have to practice for a few days before it feels natural.
Apart from this, there isn’t any downside, except of course family members will have difficulty using your camera because they are not used to using back button focus. (For some this might be an advantage having the camera to themselves :-)).
How to Set Up Back-Button Focus on Your Camera?
In summary, with many modern day DSLRs or Mirrorless cameras from many of the major brands, you can adjust the camera’s focus mode three ways (typically shown as an ‘AF-S’, ‘AF-C’ or ‘M’).
With the use of the back button focus you can keep the camera in continuous focus mode (AF-C) all the time and just press the dedicated back button to activate autofocus or reach for the manual ring on your lens to adjust the focus manually. That’s a lot easier right.
The benefits of this mode far outweigh the traditional method, which is why many professionals eventually opt for this system.