Image illustrating light beams passing through a weak biconvex or converging lens. This simulation parallel beams of monochromatic light striking a converging lens. Notice how the rays converge to the right of the lens. However, they do not form a perfect focus. This is due to spherical aberration. This differs from versions #1 and #2 in being less curved and hence a weaker converger. Notice how the rays cross further from the lens.