An apparatus and method for reducing a shutter lag in a device with a digital camera function, in which an electronic shutter can be driven in a state of a half shutter or a full shutter, and a controller controls execution of a sub-sampling preview mode if the camera function is driven, controls to fix white balance and exposure and automatically adjust a focus upon detecting an input of the half shutter during the execution of the sub-sampling preview mode, switches to a full-pixel preview mode after completion of the adjustment, and performs image capturing upon detecting an input of the full shutter.