In one embodiment, a method for operating a camera included in a touch input device including a touch screen is disclosed. A processor determines a capacitance pattern for a varying capacitance throughout the touch screen when the touch screen is underwater and no touch input occurs. The processor resets a varying reference capacitance for determining whether a touch input by an object occurs or not, the varying reference capacitance being reset based on the determined capacitance pattern when the touch screen is underwater and no touch input occurs. The touch screen receives a touch pressure by the object underwater. Operation of the camera is controlled according to the touch pressure to the touch screen.