If there were only one thing I could choose to have learned earlier in my photography journey it would be back button focusing. Like most new photographers, I was disappointed at the amount of times a great image was ruined by soft focus. Back button focusing totally changed the game for me and now we rarely ever experience out of focus images. It's so easy to change you should RUN, not walk and change your camera now.
Why you Should Start Using Back Button Focus
There are so many advantages, but let's focus on photographing moving subjects. Wedding days, family photos, and toddlers... there really isn't a genre of photography that wouldn't benefit from switching to BBF.
Using back button focus allows you to nail the shot by utilizing the continuous focus mode on your camera. I shoot weddings, so I'm constantly capturing moving targets. I keep my camera on continuous focus mode all the time and utilize back button focusing to ensure my photos are tack sharp.
Canon: Al Servo
If you are using back button focus, you can take a series of images while maintaining focus on your subject. I use this a lot when a couple is snuggled up in a pose and they start giggling and laughing or while they are walking down the aisle towards me. Holding the back button while pressing the shutter allows the camera to keep them in focus even while moving and taking a series of shots. With my finger always on the BBF button and pressing and holding both the shutter and AF button at the same time- the actions of focusing and taking the photo happen together rather than with a delay that could cause the image to become out of focus.
IF you are ready to jump right in, here's how to Change Your Camera to Back Button Focusing