Nikon D3100 D3100 User's Manual - Page 56

5 Focus. Press the shutter-release button halfway to focus. Face-priority AF: The camera sets focus for the face in the double yellow border while the shutter-release button is pressed halfway; if the camera can no longer detect the subject (because, for example, the subject has looked away), borders will no longer be displayed. Wide- and normal-area AF: The camera focuses on the subject in the selected focus point while the shutter-release button is pressed halfway. x Subject-tracking AF: The camera focuses on the current subject. To end tracking, press J. D Subject Tracking The camera may be unable to track subjects if they are small, moving quickly, or a similar color to the background, or if both the subject and the background are very bright or very dark, the brightness and color of the subject or background varies greatly, the subject leaves the frame, or the subject visibly changes size. The focus point will blink green while the camera focuses. If the camera is able to focus, the focus point will be displayed in green; if the camera is unable to focus, the focus point will blink red. Note that pictures can be taken even when the focus point blinks red. Check focus in the monitor before shooting. Except in i and j modes, exposure can be locked by pressing the AE-L/AF-L button (0 80). Focus can be locked by pressing the shutter-release button halfway. 40