Continuous Tracking Autofocus

Continuous Tracking Autofocus

Using the AFS or One Shot focus mode may work well  for a portrait, an inanimate object or a landscape photograph, but what about a moving subject? When trying to photograph a moving subject the camera lens to subject distance is continually changing. If the camera locks the focus at one point the subject has immediately moved nearer or farther from the camera and is out of focus when the shutter is released. To photograph moving subjects such as sports, vehicles or birds in flight you will need to locate the AFS or AI Servo focus mode.  In these modes the autofocus system will track a moving subject and continually maintain focus as the subject to camera distance changes. You will also want to select a focus area (dynamic AF-area) such as a zone or multipoint selection.  Since it is very difficult to maintain a single focus point on a moving subject the camera will utilize this dynamic area to maintain focus as the subject and camera move.

Dynamic AF-Area Mode

In “Dynamic” (Nikon) or “AF Point Expansion” (Canon) AF-Area Mode, you still choose one focus point and the camera will initially acquire focus on that particular focus point. However, once focus is acquired, if your subject moves, the camera will utilize the surrounding focus points to track subject movement and keep focus on your subject. You are expected to track the subject by panning the camera along with the subject and making sure that the subject stays close to the initially selected focus point.

Your actual focus grid may appear different then the example below, but the principle will be the same. The central autofocus point will be given priority and the additional focus points surrounding it will actively assist in maintaining the focus. How many focus points you choose will depend on your camera, lens, the subject matter and your experience as a photographer.

TIP: You may also want to set the camera shutter to fire continuously. Combining the tracking focus with the continuous drive mode allows you to take multiple shots of a moving subject. Consult your camera manual if you are not sure how.