A zoom lens includes a first lens group, a second lens group, a third lens group, an aperture, a fourth lens group, and a fifth lens group in order along an optical axis from an object side to an image side. The first lens group has positive refractive power, and includes four lenses. The second lens group has negative refractive power, and includes three lenses. The third lens group has positive refractive power, and includes one lens. The fourth lens group has positive refractive power, and includes five lenses. The fifth lens group has positive refractive power, and includes one lens. The zoom lens is switched to the telephoto mode from the wide-angle mode by moving the second lens group and the fourth lens group toward the third lens group.