Whirring noise P7100
Check wether the autofocus mode is set to AF-S or AF-F. If set to AF-F (full time AF), the camera focuses and refocusses at all times, even when the shutter release button is not pressed. The movement of the lenses generate a faint noise, also in my P7100. Once you press the shutter release button half down, the actual focus is locked and the noise is gone.