Back button focus, you’ve heard, can change your life! You just might never miss focus again if you switch to BBF.
Sounds too good to be true, right?
Back button focusing is a special way to set focus on your camera. By special, I mean that your camera isn’t set to BBF by default. You have to dive into a menu and change the settings in order to make it work.
BBF is technically defined as “a separation of exposure and focus.” Here’s what that means in real English:
When you unpack your camera from the box and take your very first photo (without changing any settings), 4 things happen when you press that shutter button:
- The camera decides what the most important part of your photo is.
- The camera choose how to expose the photo based on a calculation that weights the important area.
- The camera focuses on that important area.
- The camera takes a photo.
When the camera is choosing what to focus and set exposure on, it’s going to default to what is closest to the camera and to what’s in the center of the frame. Think about a photo where you’d like to focus on your subject who is off center and who has plants in front of her that you’d like to blur. Your camera will most likely focus on the plants rather than the subject.
In this case, you might like to set focus on your subject and have the camera choose exposure after you’ve composed the image. In this situation, people use BBF to point the camera at the subject, press the button on the back to set focus, recompose the camera and press the shutter button to set exposure and shoot. BBF ensures that your focal point doesn’t change when you press the shutter button. It only changes when you press the “button on the back.”
That is the benefit of BBF in a nutshell. Sounds simple, right?
For some shooters, BBF can be very important. For others, it can add a lot of stress with very little added benefit. So let’s talk about who needs it and who doesn’t.
If you answer yes to either of these questions, it’s my opinion that you probably don’t need BBF.
- Do you choose your focal point with joystick or dial? BBF will be of no value. You are already focusing on exactly what you want, and pushing the shutter button will not change it.
- Do you shoot full auto? If so, you don’t have access to BBF.
Back button focus might help those who:
- Focus and recompose. This is a way of using Auto Focus and tricking your camera into focusing on what you want. You point the camera at your subject, push the back button to set focus, and then compose the shot as you’d like. Depressing the shutter button only sets exposure in this case, not focus. However, the camera will focus on whatever is closest to it, including those branches in the foreground that you might want to blur.
- Shoot on Servo or Continuous focus tracking. This is a focus mode where focus can track a moving subject. It can be good for sports, toddlers, etc. I don’t like it for one reason – it doesn’t beep when you achieve focus. I like that beep giving me confirmation that focus is locked! When you use Servo or Continuous (Nikon-speak) in conjunction with BBF, you hold down the back button continuously to track your subject. Release the button to hold focus static (if your subject stops moving).
I used to shoot BBF, but realized that it was redundant when I began shooting with manual exposure and choosing my focus point. I shoot on manual all the time now, and I always select my focus point using the joystick on the back of my camera. Of course, not all camera have a joystick – some have a dial – but most cameras do let you choose where to focus.
My 6D, for example, has 9 focal points to choose from. The Mark III, on the other hand, has sixty-freakin’one!
When I shoot, my routine is:
- Point my camera at my subject and dial in the exposure indicated by my meter.
- Compose the shot.
- Set focus, making sure that one of my 9 focal points is over my subject. This might involve a slight composition adjustment.
A Note on the Focus and Recompose Method
Some people swear by this method. And if you are one of them, don’t change a good thing. However, if you find that you miss focus more than you’d like, know that this is a risky way to shoot. Especially if you like wide open apertures. When you aim your camera and focus with your subject at the center of the frame, then move the camera as you recompose, you are changing the focal plane ever so slightly. This tiny movement can make a big difference in terms of sharp photos, especially, as I said, at wide apertures.
One benefit of focusing and recomposing is that the center focal point is usually “stronger.” This doesn’t mean that focus is better. It might, however, mean that focus is faster. But if you’re focused, you’re focused, no matter which focus point was used to achieve focus.
Setting Focal Points Manually
For me, choosing the focus point manually, after I’ve composed the shot, is the best way to find precise focus. Here’s my method.
The Red Dot that Shows You Where You’ve Focused
Want some feedback over where you focused after you shot the photo? Turn on your red dot. However, if you focus and recompose, this dot will always be in the center of your photo and won’t provide meaningful feedback.
How to Set BBF
Ahhh. That’s a question for your camera manual. Look for menu settings called Auto Exposure/Auto Focus, or Focus Lock, or something similar. The manual will tell you not only how to enable this feature, but also which button on the back it uses!
Am I Wrong?
This is a question that people feel very strongly about. I’d love for you to convince me that I’m wrong. Is there another reason that shooting BBF would give me better focus? Share it in the comments below.