AUTO FOCUS APPARATUS USING LINEARITY AND A METHOD THEREOF

An auto focus apparatus and an auto focus method using linearity are provided to minimize time required to perform auto focus by determining a position to which a focus lens is moved using linearity of an auto focus data value. An auto focus apparatus includes a focus lens, a DSP(Digital Signal Processor)(250), and a controller(260). The focus lens is moved between an infinite focus point and a close-up focus point in order to focus an object image. The DSP calculates auto focus data values from an image signal of the object, received from the focus lens. The controller receives the auto focus data values from the DSP and calculates the linearity of the auto focus data values. When it is determined that the auto focus data values are reduced based on the linearity, the controller moves the focus lens to the focus point having the largest auto focus data value among the focus points through which the focus lens is moved.