According to the apparatus and method of the present invention, the motion vector Vij is weighted by the weighting coefficient \u03b1ij of the motion vector Vij decided based on the AF evaluation value Iij indicating the degree of sharpness of the subject image so as to decide the entire motion vector V. The system and method are capable of performing these tasks without the use of non-standard container tagging. These hooks engage with the open neck of the sandbag and hold the top of the bag open. Furthermore, because the retainer attaches directly to the circuit board component and to the heat sink, the retainer minimizes the necessity for use of mounting holes in the circuit board associated with the circuit board component to secure the heat sink to the circuit board component. A plurality of support flanges are fastened to each interior member and corresponding side member for additional structural support.