Patent ID: 7667900

Claim:
A zoom lens system having only two lens groups, the two lens groups being, in order from an object: a first lens group having negative refractive power; and a second lens group having positive refractive power, wherein upon varying a state of lens group positions from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group decreases, the first lens group consisting of, in order from the object, a first lens having negative refractive power and a second lens having positive refractive power, the second lens group consisting of, in order from the object, a third lens having positive refractive power, a fourth lens having negative refractive power, and a fifth lens having positive refractive power, the third lens, the fourth lens, and the fifth lens being disposed with at least one air space in between, and the following conditional expression being satisfied: 0.76< S 2/ fw< 1.30 where S 2 denotes a thickness of the second lens group, and fw denotes a focal length of the zoom lens system in the wide-angle end state.