US Patent 8405914 Zoom lens and image pickup apparatus

A zoom lens includes: a first lens group with a positive refractive power, including a reflection optical element; a second lens group with a negative refractive power; a third lens group with a positive refractive power; a fourth lens group with a positive refractive power; and a fifth lens group with a negative refractive power. A power of the zoom lens varies by moving the second lens group, the fourth lens group, and the fifth lens group along an optical axis. A negative lens in the first lens group or a positive lens in the second lens group satisfies the predetermined conditions relating to a refractive index and an Abbe number.