How To Use Back Button Focus + AI Servo | Canon DSLR
February 07, 2016 |
| Back button focus. |
What Is Back Button Focus?
Typically when you half press the shutter button you hear a 'beep' to lock focus on your subject, then you fully press the shutter button to take the shot. Essentially, the shutter button both controls the focus and takes the photo, this is certainly the way I first learnt to use my DSLR.
Back button focusing (BBF) separates these two functions by assigning focus to another button (on a Canon DSLR this is usually the AF On button located on the back of the camera). This means you have one button to focus and the shutter to simply to take the photo.
Before switching for back button focus, every time I wanted to change composition or moved slightly after half pressing the shutter button I would have to re-focus. Similarly, if my subject was moving it was impossible for me to lock focus and get a sharp image. It was annoying because I wasted a lot of time just trying to find my focus again.
With BBF however, pressing the AF-On button once locks my focus until I press the shutter to take the photo (given that the distance between you and the subject remain the same). This means once you have locked in the focus you have the freedom to recompose the image if desired. No more switching between focal points, now I always have mine set in the centre!
Back button focusing (BBF) separates these two functions by assigning focus to another button (on a Canon DSLR this is usually the AF On button located on the back of the camera). This means you have one button to focus and the shutter to simply to take the photo.
 |
| Back Button Focus | AF-On Button. |
How It Can Improve Your Photography Experience?
Focus and RecomposeBefore switching for back button focus, every time I wanted to change composition or moved slightly after half pressing the shutter button I would have to re-focus. Similarly, if my subject was moving it was impossible for me to lock focus and get a sharp image. It was annoying because I wasted a lot of time just trying to find my focus again.
With BBF however, pressing the AF-On button once locks my focus until I press the shutter to take the photo (given that the distance between you and the subject remain the same). This means once you have locked in the focus you have the freedom to recompose the image if desired. No more switching between focal points, now I always have mine set in the centre!
BBF + AI Servo
Taking photos of a moving subject?
BBF used in conjunction with AI Servo mode (Canon) make shooting moving subjects a lot easier. This was one of the problems I had using One Shot and the shutter for both focus and shooting, I could never get a sharp image of a moving subject.
AI Servo tracks focus of a moving subject as it moves towards or away from your camera. In this mode when taking pictures of your subject moving towards you, simply hold down the AF-On button while taking pictures, this way the camera automatically tracks focus of your moving subject resulting in sharper images. That's why it is widely used in wedding photography when taking photos of the newly weds walking down the aisle. Ahh, it all makes sense now.
Tip:
AI SERVO can be found by pressing the AF Button (next to Drive and ISO) on top of the camera.
AI Servo tracks focus of a moving subject as it moves towards or away from your camera. In this mode when taking pictures of your subject moving towards you, simply hold down the AF-On button while taking pictures, this way the camera automatically tracks focus of your moving subject resulting in sharper images. That's why it is widely used in wedding photography when taking photos of the newly weds walking down the aisle. Ahh, it all makes sense now.
Tip:
AI SERVO can be found by pressing the AF Button (next to Drive and ISO) on top of the camera.
How to Switch to Back Button Focus | Canon
I've also listed some helpful links below which guided me in making the switch to BBF. Try it out and let me know what you think.
- Back Button Auto Focus Explained
- One Shot vs Al Servo: When To Use Each
If you've found this post helpful, I'd like to hear from you! Or sign up to the mailing list so you won't miss out on future posts!
Happy Shooting!
Happy Shooting!
___
Come and say hello!
0 comments