A digital camera feeds information input on an operation panel to a system controller. The system controller generates a control signal in accordance with optical sensitivity selected and feeds it to a timing signal generator. The timing signal generator includes a signal generator, which generates a timing signal whose frequency matches with the control signal. While a solid-image image sensor is driven by the timing signal, the frequency of a horizontal transfer signal is made lower than the usual frequency in accordance with the sensitivity selected. This prevents the number of electrons from noticeably decreasing during horizontal transfer to thereby enhance transfer efficiency for a single stage of transfer.