The invention provides a camera system. In one embodiment, the camera system comprises a camera module and a processor. The camera module photographs a target object according to a focal length to generate an image. The processor comprises an extending-lens-depth-of-filed (EDOF) module and an auto focus module. The EDOF module processes the image according to an EDOF process to generate an EDOF image. The auto focus module adjusts the focal length of the camera module according to an auto focus process.