In most cases, we have fixed field of view (FOV) lenses. The Horizontal Field of View (HFOV) is the angle subtended across the horizontal axis of the camera. In the case of the 320 x 240 cameras, 320 pixels will be imaged across the HFOV. The wider the FOV, the larger the scene, but the smaller the resolution in angular coverage per pixel. The same holds true for the 640 x 480 cameras. Please review the video to see the differences. With a fixed FOV lens, the only way you can increase the resolution of a particular object you want to see is to get closer to that object.