Back button focused on the subject's eyes nailed focus while subject was in motion - Copyright: Michael Rich
After choosing to never delete any photos I take again, I decided to review my catalog in Lightroom to see if there were any trends in my photography that were causing me to miss lots of shots. I found one right away.
Focus
I have missed many a shot due to being out of focus. Now you’d think that this shouldn’t be a problem any more since I have been taking photos quite frequently for the past few years. I should have figured this out already right? Well I guess not, and this is probably because I have been deleting all of my out of focus pictures in the field and not giving them a second thought afterwards.
Now there can be many different reasons why you are getting out of focus pictures, some obvious, some not so. Here are the usual suspects:
- Shutter speed is too slow
- Focusing on the wrong area of the frame
- Subject moving out of the focus plane
- Depth of field too shallow
- Not enough light for auto focus to work correctly
- Not enough contrast in the scene for auto focus to work correctly
The culprit in my case most often was the subject (typically my 11 month old daughter) moving out of the focus plane. When you are shooting with a shallow depth of field like f/2.8 or greater, it is easy to miss your focus when the subject moves toward your camera or further away, especially when you are focusing and then recomposing your shot. I have found that there is one great, life saving feature found on any Canon camera that will solve this problem.
Back Button Auto Focus
This feature rocks! Basically it separates your shutter release button and your auto focusing button. Here is what Canon has to say about the feature:
Easier to lock focus
If you are shooting something like a series of portraits of a person, and you want them composed off-center, back-button AF makes it super-easy to take as many pictures as you want. Focus on your subject by pressing the rear button (more on which button later in this article). Once in-focus, take your thumb off the rear button. Re-compose the shot to move your subject off-center. Shoot as many pictures as you like. With focus activation removed from the shutter button, you now can fire any time you like, and remove your index finger from the shutter button after a shot is taken. No matter what, the camera makes no effort to re-focus when you press the shutter button half-way down again.
Easier timing of shots
Similar to point number one above, but yet another benefit of pulling focus away from the shutter button is that critical timing becomes simpler to manage. For example, if you were shooting a speaker at a podium, he or she might periodically look up or make a gesture that would be an ideal instant to capture. If you’ve focused with back-button AF, your index finger is free to shoot at the decisive moment. There are no worries about holding your finger half-way down and waiting, waiting, waiting in that position for your subject to do something interesting.
Even with a very animated subject that may be moving around, you can have your camera’s focus set to AI Servo AF (to track any movement), and just keep your right thumb on the back button to keep focus active, while your index finger can be ready to shoot with no worries about also preserving focus.
Less risk of focus errors with moving subjects
For sports photographers and others taking action pictures, back-button AF lets you stop focus whenever something might interfere with the moving subject you’re tracking — without requiring you to stop shooting. In sports, for instance, it’s common for a referee or another player to come between the camera and an athlete being photographed. With back-button AF, it’s easy to momentarily pull your thumb off the rear button, and you can still keep shooting by pressing the shutter button fully. The camera instantly stops focusing when your thumb comes off the back button. Once the obstruction is out of your way, you can immediately pick-up your primary subject by pressing your thumb on the back button again.
I found this video to explain how to set the back button focusing.
I hope this helps any of you Canon shooters who are having difficulty achieving good focusing results.
I am not covering other issues about focusing, such as not having enough contrast in the scene, too slow shutter speed, etc, but if you have any questions about those just leave a comment or ask me on twitter.
If you have any tips of your own I’d love to hear them and learn from you. Thanks for reading!