Abstract: A portable video camera with adjustable motor driving signals for optimizing power consumption including a zoom lens and a focusing lens driven by stepping motors, a drive signal generating circuit for generating drive signals to the stepping motors, an external input device for receiving an external motor driving speed and motor direction input from a user, a control circuit for estimating drive loads to the stepping motors based on the external motor driving speed and motor direction input from the user and for producing an amplitude control signal corresponding to the external input, and a circuit for controlling an amplitude of the drive signals based on the amplitude control signal produced by the control circuit for estimating drive loads and for feeding the amplitude of the drive signals to the drive signal generating circuit.