Nikon D3s Body Only User Manual - Page 108

Getting Good Results with Autofocus Autofocus does not perform well under the conditions listed below. The shutter release may be disabled if the camera is unable to focus under these conditions, or the in-focus indicator (●) may be displayed, allowing the shutter to be released even when the subject is not in focus. In these cases, use manual focus (pg. 83) or use focus lock (pg. 80) to focus on another subject at the same distance and then recompose the photograph. N There is little or no contrast between the subject and the background Example: subject is the same color as the background. The focus point contains objects at different distances from the camera Example: subject is inside a cage. The subject is dominated by regular geometric patterns Example: a row of windows in a skyscraper. The focus point contains areas of sharply contrasting brightness Example: subject is half in the shade. Background objects appear larger than the subject Example: a building is in the frame behind the subject. The subject contains many fine details Example: a field of flowers or other subjects that are small or lack variation in brightness. 82