Today’s Question: I recall at a presentation you gave that you said back button focus allowed you to have the choice between continuous autofocus and one shot autofocus at any time. Can you explain how that is possible?
Tim’s Quick Answer: You can have both continuous or one-shot autofocus at any time when using back button focus by simply setting your autofocus mode to continuous autofocus. Then press and hold the focus button on the back of the camera to achieve continuous autofocus. When you want one-shot autofocus, press and hold the button to initially achieve focus, and then release the button so the focus will not change until you press the button again.
More Detail: The ability to instantly switch between one-shot autofocus and continuous autofocus is one of the key reasons I prefer to take advantage of the ability to use a separate button on the back of the camera to initiate autofocus. This provides considerable flexibility when photographing a variety of different subjects under changing circumstances in a short period of time.
In addition, back button autofocus enables you to separate the metering functions of your camera from the focus functions, which also provides considerable flexibility in your photography “workflow”.
For more information about back button autofocus, see the article “Back Button Focus” in the July 2015 issue of Pixology magazine. If you’re not already a subscriber you can sign up today and request the back issues at no additional cost by sending an email to renee@timgrey.com. Details about subscribing can be found here: