A method of operating an image pickup system includes generating a first control signal in response to a long duration exposure mode selectively input by a user, setting circuits to process image data associated with modes other than long duration exposure mode to a standby mode in response to the first control signal, generating a second control signal when the standby mode has been established, opening a shutter in response to the second control signal, and performing a long duration exposure to accumulate a charge corresponding to an optical signal incident on an image sensor of the image pickup system when the shutter is open.