April 21, 2018
Back Button Focus
The hidden feature that guarantees sharper photographs
Most camera manufacturers ship their digital cameras with a complicated way to focus on the subject you are taking. If you have moved from letting the camera to decide where to focus and use a single point, then you’ll have got into the habit of half-pressing the shutter button to focus and then re-composing the frame to put the focus point in the right place. This method of focussing harks back to a time pre-digital when film cameras had a mechanical focus and shutter mechanism. If only there was a simpler way! Do you know what? There is a simple way on pretty much every DSLR. Back button focus was introduced in 1989 to the EOS 630 film camera and since then all manufacturers have followed suit.
You can set up your camera so that there is one button to focus and then the shutter button does exactly what it says – triggers the shutter. On the back of your camera, there will be a button labelled – AF-ON, AE-L, AF-L or something similar. With just a few keystrokes you can assign this button so that it is responsible for focus leaving the shutter button to do its job.
There are also some added benefits to using back button focus.
You don’t need to switch to Manual Focus
When I am taking landscape photographs I want my focus point to be really sharp. To do this I switch my camera to live view and then magnify the scene on the screen and manually focus on the specific point. If I used the traditional method of pressing the shutter button, I would need to switch the lens to Manual Focus to stop the shutter re-focussing. By using back button focus you can leave the lens in Auto Focus mode as the shutter no longer impacts the focusing. Before I switched to back button focus I can remember being really annoyed when I hadn’t switched my lens back to Auto Focus and missing a shot. So back button focus actually makes you a calmer person!
You can keep your camera in AI-Servo Mode
AI-Servo (or AI-Continuous on Nikon cameras) is great if you are photographing subjects that move. When using back button focus you can either press the AF-ON button once and it will remain focused on that single point. If the object is moving, you can press and hold the AF-ON button and with AI-Servo mode on the focal point will follow the object once you have locked on it. Great for sports photography.
Once you are focussed you don’t need to refocus
Imagine you are photographing a person and you are taking many poses. With the traditional method, every time you press the shutter button you then need to re-focus on the subject. Not with back button focus. As long as you stay the same distance from the subject, once you have focussed once you don’t need to refocus until they (or you) move backwards or forwards. You take fewer photos where the focus has slipped using back button focus so you have more keeper images.
How do I find how to back button focus?
This is where camera manufacturers make things complicated. They hide the steps away in different menus. When I run my Switch to Manual photography workshops I come across a whole variety of brands and models and each one is different. However, each brand is approximately the same, so I’ll show one model for Canon, Nikon, Sony, Panasonic and Fuji and this should cover off most digital camera makes and give you a good idea of where to look.
- Press Menu and go to Custom Controls menu
- Scroll to the shutter button and press OK. Set the option Metering Start
- Scroll to the AF-ON button and press OK. Set the option Metering &AF Start
- Press Menu and go to the Custom Settings Menu
- Go to Controls and choose F5 Assign AE-L/AF-L button
- Choose AF-ON
- Choose Menu > Custom Settings > Pre-AF > Off
- Choose Menu > Custom Settings > Custom Key Settings > AEL Button > AF-ON.
- Choose Menu > Custom Settings > Custom Key Settings > AF/MF Button > AF/MF Ctrl Toggle.
- Choose Menu > Custom Settings > AF w/shutter > Off.
- Press menu and go to Custom Settings
- Turn AE/AF Lock to ‘AF-ON’
- Turn Shutter AF to ‘Off’
- Switch Focus Release Priority to ‘FOCUS’
- Get out of setting by tapping the shutter
- Open AF area mode and select ‘1-Area’
- Press Menu and scroll down to Autofocus Settings
- Scroll to Instant AF Setting and set to AF-S
It’s not worked – HELP!
These keystrokes work on some models of the cameras from each manufacturer but a bit of a health warning – some manufacturers do change their menus and they disappear off to somewhere else. If the menu of your camera doesn’t have this option and you want to set up back button focus, there is usually someone that has posted the exact keystrokes for your camera. A quick Google search will get you there.
Almost from the first day that I switched to back button focus, I started to get more shots in focus. You’ll probably take a day or so to get used to pressing and releasing the focus button (or holding it for moving subjects). Once you have though, I can guarantee you’ll never go back to that half-button press.
Like to learn more ways to take great photographs? The Switch to Manual Workshop in Edinburgh is a fun way to learn how to use your camera and take better pictures