In this paper, we introduce chromatic aberration as a source of visual information that can be useful for auto-focus and depth estimation. A color video camera equipped with a lens with chromatic aberration has been used to take images of both step and occlusion edges at several distances from the camera. The defocus measures obtained in the three different RGB color channels of each image are different. We suggest the way this information can be exploited in order to design an auto-focus sensor, and how depth information can be derived.