An autofocusing method is implemented in an image capture device comprising a lens and a sensor module. The relative positions of lens and the sensor module are adjusted for autofocusing based on a factor. First, the relative positions of the lens and the sensor module are adjusted based on a first unit of the factor to determine a plurality of states of the lens and the sensor module, where the lens renders clearer images on the sensor module. The states are utilized to estimate a best state achievable by focusing based on a second unit of the factor, where the lens renders a clearest image on the sensor module. The second unit is finer than the first unit. The lens or the sensor module is driven to the best state.