A focus method and a photographic device using the method are disclosed. The photographic device comprises a zoom lens, an image analyzing module, a focus distance providing module and a processing module. The zoom lens is used for capturing image information of a plurality of positions; the image analyzing module is used for analyzing contrast values of the image information of the plurality of positions; the focus distance providing module is used for providing a non-equivalent and a constant focus distance interval for capturing the image information of the plurality of positions; and the processing module is electrically connected with the zoom lens, the image analyzing module, and the focus distance providing module. Whereby, the photographic device acquires the image information of the plurality of positions by the non-equivalent focus distance interval and acquires a coarse focus position, and acquires an accurate focus position by the constant focus distance according to the coarse focus position.