The Ultimate Guide to Back Button Focus for Pet PhotographersJun 09, 2017
Welcome! You're probably here because you've heard about this mystical "BBF" - and wondered what it is and why people would want to use it. A fellow pet photographer and friend taught me this method several years ago and it seriously Changed. My. Life.
The lady on the left there is the wonderfully talented Sarah from McGraw Photography. I met up with her and several other amazing pet photographers in 2013 during a trip to the USA and she introduced me to back button focus. I have never looked back and always remain totally grateful!
I’ve since passed this technique onto many of my mentoring and workshop students and photographer friends. All who have tried it, despite needing a little adjustment time to get used to it, have adopted this technique and now swear by it!
What back button focus ISN'T
Before you dive headlong into this blog post, I would just like to emphasise one thing. Back button focus is not a magic button that will make all your photos perfectly sharp overnight - it is simply a focusing technique. There are many pieces of the puzzle when it comes to obtaining sharp focus for action photos and I highly recommend you check out this blog post before you read any further - 10 Tips for Taking Better Action Photos of Dogs.
"Spare me the lengthy blog post - I just want the important facts!"
Okay, okay! If you're fairly experienced and just want the basic rundown about back button focus - here you go...
- Pets are not static subjects
- Shooting in full time continuous auto focus will mean a much higher percentage of sharply focused images - for portraits AND action
- Using back button focus allows you to leave your camera in continuous auto focus full time
- Back button focus allows you to easily focus and recompose if you need to
If you still have questions after reading that super quick summary, then read on...
About focus points and auto focus modes
Let's go over a few focusing basics first.
Focus point selection
Your available focus points will vary greatly depending on what camera model you have. As a general rule, higher end professional camera bodies have more available focus points over a wider area of the image. All digital SLR cameras will have the option of selecting just a single focus point - but just to confuse things they'll also have a range of other options - full auto using all points, various groupings of four or more points, a single point with surrounding assist points, zones and groups and all manner of configurations - oh my!
For the purposes of this blog post, we're going to be focusing on (sorry, had to use that pun at least once) using just one single focus point.
Because you're a super creative person, what you want to focus on won’t always be in the middle of the frame. This means you'll need the ability to quickly move that focus point to where you need it. This may require some customisation of the camera controls. My camera has a "multi-controller" knob on the back near my thumb that I’ve customised to control focus point selection.
My advice is to read your camera manual to find out how you can set up your camera to quickly switch focus points - as this is instrumental in making back button focus work for you.
See that little knob my thumb is on? To change focus points I just move this up/down/left/right to select a different point. I can move my thumb to there very easily from the AF-ON button, so I don't need to stop looking through the viewfinder. Very convenient!
Let's move onto focus modes...
Single shot auto focus (One Shot on Canon, AF-S on Nikon)
Single shot focus mode is designed for photographing non-moving subjects. With your camera set up as standard, depressing the shutter button halfway causes the camera to obtain and lock focus. This is usually accompanied by a LED flash and notifying beep.
Pros: Because the camera flashes and beeps, you know exactly when focus has been locked. If your designated point is outside the range of your available focus points, you can use a technique called "focus and recompose". After locking focus, you keep your finger half-pressed down and reframe the shot by moving the camera slightly, then fully depress the shutter to take the shot.
Cons: Single shot mode is designed for static objects - but dogs aren’t static objects. Even when they’re sitting "still" they’re always moving ever-so-slightly. If the dog moves, just a little, in the time that it takes for you to press the shutter the whole way down, the focus may be missed. When shooting with a shallow depth of field, this can mean the difference between obtaining a super sharp well-focused shot, or one where the focus is slightly forward or back from where you intended.
This mode is not designed for moving subjects - so you'll always need to switch to continuous auto focus for action shots.
Continuous auto focus (AI Servo on Canon, AF-C on Nikon)
This is the perfect focusing mode for moving objects - and we've already established that dogs (and pretty much all other pets and animals) are constantly in motion.
Pros: When the camera is told to start focusing, the autofocus system locks on to the subject and starts continuously tracking it’s movement - whether it’s the tiny movements of a dog sitting stationary - or the fast motion of a dog running full tilt towards you. While auto focus is activated, the camera continually keeps your subject in focus.
Cons: With the camera set up as standard (focus and shutter on the same button) you cannot focus and recompose. As soon as you press the shutter after you recompose, the camera refocuses. Don't lose heart, there is a way around this using back button focus.
Now for story time...
Let's imagine a few different scenarios. We're going to talk about taking portrait style shots to start with - not action. You'll see why later on!
Photographer 1 - let's call her Amelia.
Amelia has a photo shoot with a dog outdoors at the beach and wants to obtain a wide angle shot showing his happy smiling face. He isn't very well trained but will sit and stay for a couple of seconds before running off and doing zoomies in the sand.
Since her subject is mostly still, Amelia sets her camera to One Shot auto focus mode and uses treats to try and keep his attention. She fills the frame with his face and uses the middle focus point to lock focus on one eye. While she is moving the camera to recompose, his attention is diverted to potential doggy friend further down the beach.
Amelia quickly fully depresses the shutter button to get the shot, but in the time it takes to recompose, he has looked away and the focus is no longer on his eye. She then has to get the dog's attention again and have another go - but every time she focuses and goes to recompose - he moves slightly.
Amelia ends up with just a few shots and most of them are slightly or quite out of focus.
Don't be like Amelia.
Photographer 2 - let's call him Robert.
Robert has a photo shoot with a dog in a busy park and wants to obtain a low, wide angle shot of him standing on a rock. The dog has a pretty good stay, so Robert just makes a funny noise to get his attention. Robert has his camera set up so he can quickly and easily move the selected focus point around - awesome! He is shooting in One Shot focus mode because the dog is sitting still - right?
Robert selects a focus point right over the dog's left eye. He half-presses the shutter to lock focus on his eye, then suddenly the dog decides what's happening on the other side of the park is way more interesting than the noises Robert is making.
In the time it takes for Robert to fully depress the shutter and take the shot, the dog has moved his head forwards for a closer look, and the focus of the resulting shot is now around the dog's forehead. Robert makes another funny noise and he quickly looks back, but now Robert has to lock the focus again before he can take the shot. He's missed the opportunity of the inquisitive expression the dog made when he looked back at him. Robert takes more photos but always seems to be one step behind the movement of the dog.
Maybe dogs aren't static objects after all?
Robert ends up with some out of focus shots, along with some in-focus shots, but he doesn't have many in focus shots to choose the best expression from.
Don't be like Robert.
Photographer 3 - let's call her Alison.
Alison has a photo shoot with a dog in a busy urban setting and wants to obtain a wide angle shot of the dog doing her best trick - raising a paw to wave!
Alison has her camera configured so she can quickly and easily move the selected focus point around. She also has the focus mode set to AI Servo, continuous autofocus, because she knows that dogs are not static subjects - they are living, breathing creatures that are constantly moving - even when they're sitting still - but especially when they're doing tricks like this. Alison selects a focus point right over the dog's eye. She holds her thumb down on the back focus button to lock the focus on the dog's eyeball, and her camera body and lens immediately starts working to keep the eye in perfect focus, making lighting fast, minuscule adjustments as the dog moves every-so-slightly in relation to the camera.
Alison gives the command for the "wave" and up goes the paw. The dog shifts slightly back and to the side to compensate for the movement. Because the lens has been constantly tracking focus while the focus point has been placed on the eye, when Alison presses the shutter the dog's eye is in perfect focus, regardless of the fact she was moving at the time.
Alison takes a few shots in quick succession, easy to do because the camera is constantly focusing on the moving subject. She ends up with a bunch of cool shots to choose from, all in perfect focus.
Alison is the only one of the three who consistently gets perfectly-focused images.
Best of all, because Alison is already in continuous auto focus, using back button focus, she can now go take some action shots and not having to worry about switching focus modes - another win!
Be like Alison!
There are two vital ingredients to Alison's success:
- She uses a single focus point, and moves it directly over the dog's eye
- She recognises that dogs are not static subjects, so she uses continuous auto focus
Because Alison uses continuous focus, but also needs the ability to focus and recompose or stop focus completely, she has her camera set up to use back button focus.
How is back button focus different to regular focusing?
Out of the box, most digital SLR camera bodies are set up with the shutter button programmed with two functions:
- Start focus
- Take the photo
It makes camera operation simple for basic users - one button to rule them all. But it isn’t necessarily the best option when photographing pets, where you need to be using continuous auto focus the entire time.
Setting your camera up for back button focus separates the two functions. The ability to focus is removed from the shutter button entirely and is assigned to a different button, usually located near your thumb, on the back of the camera.
With the focus removed from the shutter, it simplifies the shutter button's function. All the shutter does now is take the picture. For those who don't have fantastic manual dexterity or "feel" in their fingers, this is a godsend!
Aannnddd... you can still focus and recompose!
So why should you switch to back button focus?
Using the power of full time continuous auto focus will mean a much higher percentage of sharply focused images, especially when shooting portraits. Using back button focus allows you to leave your camera in continuous auto focus full time, which means you can switch between shooting portraits and shooting action without changing focus modes - AND and it allows you to easily focus and recompose if you need to.
Also (a big one for me)...
It saves time.
When you're photographing pets there is SO much to think about all at once. Where do I need to be for the best light? Did I just say something silly to the owner? What's that thing over there in the background that might get in my shot? Is that dog over there going to come any closer and distract my model? Oh no, a cloud just went over the sun, has my exposure changed? What lens should I be using right now, maybe a different one would be better? Where has the dog gone again?
If you're anything like me, it's a constant internal monologue!
There are many things beyond your control, but if you can control and streamline everything you possibly can, it leaves more time to devote to thinking about the stuff that really does need your attention.
Before I switched to back button focus, the number one thing that used to annoy me when it came to camera settings, was switching between One Shot mode when I was shooting portraits, and AI Servo when shooting action. Sure you can set up custom controls and re-assign buttons (depending on your camera model) to switch between the two more quickly, but it's an extra thing to remember and it does take your attention away from your subject, when it really doesn't need to.
I just love being able to "set and forget".
Setting up back button focus on your camera
Digital SLR cameras do not come with back button focus set up - you need to configure this yourself.
On newer or more professional Canon and Nikon cameras, there is a dedicated button on the back of your camera called AF-ON. If your SLR does not have this button, you'll need to assign a different button on the back of your camera for this purpose.
The shutter button will also need to be re-programmed so it no longer activates the auto focus on half-press.
Usually, there are two steps:
- Assign focus-start to a button on the back of your camera (usually AF-ON) it it's not already set up
- Remove focus from the shutter button
The steps will vary depending on your camera make and model. Rather than listing all the camera models and explaining how to set this up for each of them, I’ll direct you to use the power of the internet via a Google search. There are many articles and YouTube videos about how to set your particular make and model of camera up - just do a search for "your camera model" + "back button focus".
Using back button focus
Once setup is completed correctly, your camera will behave a little differently than what you’re used to.
Focus will only occur while you are holding down the button on the back of the camera with your thumb.
You'll probably forget to focus a lot in the first few days - stick with it though!
The shutter button now only controls actually taking the photo.
Shooting portraits with back button focus
The steps for shooting portraits are:
- Select the required focus point
- Frame the image so the focus point is over what you want to focus on - usually an eye
- Start tracking by pressing your thumb on the back button - and keep it there!
- Keep that focus point on whatever you originally chose
- Do NOT lift your thumb off the back button, or your camera will stop tracking
- Depress the shutter fully with your finger when you want to take a shot (while still keeping your thumb held down)
- If the framing is incorrect (i.e. if you are cutting off part of the dog) stop focusing the move the focus point to where you need it. Then start again from Step 2.
You can also "focus and recompose" when shooting portraits with back button focus. But I only recommend doing this if you absolutely have to. In most cases, you should be able to move the focus point to where you need it - unless you're shooting with an older camera body where the available focus points don't cover much of the frame. The more you practice moving the focus points around, the quicker you get with this and it soon becomes second nature.
To focus and recompose (if required):
- Select a focus point closest to where you want to focus
- Frame the image so that closest focus point is over what you want to focus on - usually an eye
- Obtain focus by pressing your thumb on the back button
- Lock (stop) focus by lifting your thumb off the back button
- Quickly recompose (move the camera slightly to re-frame)
- Depress the shutter fully with your finger when you want to take a shot (keep your thumb off the back button to avoid refocusing)
Note that your subject must not be moving substantially or this technique will not work.
I recommend only using "focus and recompose" when you're shooting at distance with a long lens.
Here's a few examples of moving the focus point to the edges to compose your image creatively. No focus and recompose required.
Shooting action with back button focus
I'm going to go out on a limb here and say - back button focus is really more about the ability to keep the camera in continuous focus mode full time - rather than any massive advantages when shooting action. You should always use continuous auto focus when shooting action, to allow the camera's autofocus system to do the work in locking focus and tracking movement.
For people who struggle with the finger feel or the dexterity required to modulate pressure on your shutter finger, reassigning the focusing button to the back of the camera feels more intuitive.
When shooting action, I also recommend using the highest continuous frame rate your camera offers. This varies greatly between camera models can range from 3 all the way up to 20+ "frames per second". A higher frame rate is always preferred as you’ll have more possibilities to choose from when shooting an action sequence.
As I've mentioned, focus points vary greatly between camera models but I always recommend using either a single focus point, or a very small group of points. I also recommend for action NOT moving that point towards the edges of the available points - because the points in the centre are always going to be more accurate.
The steps for shooting action are:
- Select a focus point - usually the centre points are more accurate
- Frame the image so the focus point is over what you want to focus on - usually the eye or just the face
- When the subject starts running, start tracking by pressing your thumb on the back button - and keep it there!
- Do NOT lift it off or your camera will stop tracking
- Do NOT move focus points around
- Depress the shutter fully with your finger when you want to shoot
- Shoot continuously in "burst" mode at the highest possible frame rate
For a comprehensive guide to shooting action, check out this blog post - 10 Tips for Taking Better Action Photos of Dogs
I use back button focus, but never know when to start and stop pressing the button!
Whenever you have that back button pressed, the camera is working to maintain focus. As soon as you lift your thumb off that button, the camera STOPS focusing. The focus stays at the same focusing distance as whatever it last focused on.
You should only lift your thumb off that button before taking the shot IF you are planning on recomposing (reframing) the image before you take it. And you should only focus and recompose if the subject (or whatever part of the subject you're focusing on) is staying very still.
Otherwise - keep your thumb mashed on that button the entire time. Regardless if you are shooting portraits or action!
I've been taught to use One Shot (AF-S) for static subjects, isn't it "wrong" to use continuous autofocus all the time?
There is one little bit of flawed reasoning in this... pets, dogs in particular, are NOT static subjects.
Even when they’re sitting nicely they’re still moving ever-so-slightly. Even highly trained dogs don’t sit as still as a statue - they are living, breathing creatures!
I recommend full time continuous auto focus for pet photography.
If back button focus is so good, why are professional cameras not set up to do it as standard?
I've often wondered this myself!
I've come to the conclusion that most people don't jump straight into using a professional DSLR - they start by taking photos with their phone, then they might upgrade to a compact camera, then as their photography improves, they could end up with an entry-level DLSR then finally a professional DSLR.
Most people are just used to pressing one button to take a picture. By making the camera focus and take the shot at the same time, it pretty much guarantees the image will be in focus - for basic photography anyway.
It's only when people get more advanced and understand focusing as a separate function to the shutter that separating the two things out makes sense. By keeping the shutter button responsible for both functions as standard, it makes it easier for people to jump into using a more advanced camera, without having to learn a new technique to focus straight away.
Why not just shoot with more depth of field?
Shooting at a smaller aperture increases the depth of field which can rescue a shot where the focus has been slightly missed, but it’s a shame to sacrifice the artistic quality of the shot for the sake of allowing for focusing errors. Why not just make sure you nail focus?
Why not just use the AF-OFF or AF-L button?
To address the issue of not being able to focus and recompose while in continuous auto focus mode, some photographers use an alternative method.
With most cameras it’s possible to assign one of the back buttons on the camera to "stop" focus when held down. On Canon this is called AF-OFF and and Nikon it’s referred to as AutoFocus-Lock or AF-L. Once programmed, you press the shutter halfway down to focus, then press and hold the button assigned to stop focus, then recompose and fully depress the shutter to take the shot.
Get all that? Sounds complicated, right? It is - this method can be fiddly and depends on how much fine control you have over your shutter finger.
While this method may suit some photographers, I've found that back button focus is the preferred method for most professional pet photographers.
If you have any other questions about back button focus please get in touch and I'll get back to you!
If your question relates to action photos of pets in general, make sure you check out this post first.
Disclaimer - the stories and characters here are fictional - these people are actually three of my wonderful in-person mentoring students - "Amelia" is Christine Yardy photographing Juno, "Robert" is Putra Adhitama photographing Blue and "Alison" is Rebecca Brown photographing Shaggy. You should be like all of them because they all rock!
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