This optical system (OL) has a first lens group (G1) having positive refractory power, a second lens group (G2), a third lens group (G3), and a fourth lens group (G4) which are aligned in order from an object side along an optical axis, wherein when focused from an infinity object to a short-distance object, the second lens group (G2) and the third lens group (G3) move in mutually different trajectories along the optical axis, and the second lens group (G2) and the third lens group (G3) are composed of three or less lenses in total.

The zoom lens consists of, in order from an object side, a first lens group that has a positive refractive power, a second lens group that has a negative refractive power, a middle group that includes one or more lens groups, and a final lens group. The middle group has a positive refractive power as a whole throughout an entire zoom range. During zooming, a spacing between the first lens group and the second lens group changes, a spacing between the second lens group and the middle group changes, and a spacing between the middle group and the final lens group changes. The zoom lens satisfies predetermined conditional expressions.

An optical lens, in order from an object side to an image-forming side, includes: a first lens having positive refractive power, a second lens having negative refractive power, a third lens having positive refractive power, a fourth lens having positive refractive power, a fifth lens having negative refractive power, a sixth lens having negative refractive power, a seventh lens having negative refractive power and an eighth lens having refractive power.

The zoom lens consists of, in order from an object side, a first lens group that has a positive refractive power, a second lens group that has a negative refractive power, a middle group that includes one or more lens groups, and a final lens group. The middle group has a positive refractive power as a whole throughout an entire zoom range. During zooming, a spacing between the first lens group and the second lens group changes, a spacing between the second lens group and the middle group changes, and a spacing between the middle group and the final lens group changes. The zoom lens satisfies predetermined conditional expressions.