Apparatus and method for auto-focusing in a mobile terminal

Abstract

An apparatus and method for auto-focusing in a mobile terminal having a camera module which can automatically photograph an image in optimum focus when the camera function is used are provided. The apparatus and method comprise detecting the subject by performing a preview mode in a camera mode; detecting and storing a focus value while moving the lens by increasing/decreasing electrical current in stages based on a focus characteristic of the detected subject, determining based on a presently-detected focus value and a previously-stored focus value if a slope has changed, and detecting an optimum focus value from a focus value at which the slope has changed; and performing a tracking mode to track a focus in a predetermined zone which includes the detected focus value at a center of the zone. Therefore, the value of electrical current, which is applied to the camera module including the lens that moves to perform the auto-focusing for photographing an image in optimum focus, is controlled according to a distance between a subject and a lens so that the occurrence of unwanted sound caused by motion of the lens can be prevented.