A camera system includes an interchangeable lens and a camera body. The camera body includes an image data generating unit for capturing a subject image to generate image data, a detecting unit for detecting a contrast value of an image represented by the image data generated by the image data generating unit, and a signal generating unit for generating a control signal controlling the driving unit. In an autofocus control, the signal generating unit generates the control signal controlling the driving unit to drive the focus lens at a first speed until a predetermined time elapses after the first detecting unit starts to detect the contrast value of the image and to drive the focus lens at a second speed higher than the first speed after the predetermined time elapses.