Abstract: A handheld stabilizer for automatically stabilizing a camera device, such as a smartphone, when the camera device is mounted on the stabilizer is provided. The stabilizer comprises a camera device mount for holding the camera device, a plurality of motors collectively arranged to cause the camera device mount to be rotatable about three predetermined substantially-orthogonal axes, an inertial-measurement unit (IMU) sensor for measuring an angle and an angular velocity experienced by the camera device about each of the three axes, and a controller. By means of the IMU sensor, an attitude of the camera device is measured. The controller is configured to estimate an attitude error of the camera device according to the measured attitude, and to automatically control the plurality of motors in response to the attitude error so as to controllably rotate the camera device about each of the three axes to counter the attitude error.