Focus and Recompose
The technique of focusing with a central point, locking, then shifting the camera to place the subject elsewhere in the frame.
In depth
Rotating the camera after locking moves the subject along an arc rather than in the sensor plane, so the focus distance changes slightly — an error that is invisible at f/8 and fatal at f/1.4 with a close subject. Where wide-coverage autofocus or eye detection is available, moving the point instead is more accurate.
Examples in practice
Locking on an eye at 1.5 m with a 50 mm f/1.4 and recomposing by 20° pushes the eye behind the plane of focus.