Light beams passing through a strong biconvex or converging lens

Image illustrating light beams passing through a strong 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 more curved and hence a stronger converger. Notice how the rays cross closer to the lens.