Apparatus and method for electronically estimating focusing distance between a camera (still and/or video camera) and a subject. Images at different focal positions of a calibration target are collected to arrive at a focus matching model for a given imaging apparatus. In operation, at least two images are captured and convolutions performed which approximate the modeling of blur change as a point spread function. Wavelet transforms are applied to the images after each convolution and images are compared based on the wavelet variance differences to provide a motion robust blur difference determination. Applying the blur differences to the focus matching model provides an estimate of focusing distance, which can be utilized such as for controlling camera focus.