Patent ID: 7848029

Claim:
A retractable zoom lens that includes sequentially from an object side, a first lens group havingpositive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power, wherein the third lens group comprises sequentially from the object side, a first lens that is a positive lens, a second lens that is a positive lens, and a third lens that is a negative lens, a conditional expression, 2.5≦(β 323W ) 2 ×(β 4W ) 2 ≦3.5, is satisfied, where β 323W denotes a combined imaging magnification of the second lens and the third lens of the third lens group, at a wide angle edge at an infinite object distance and β 4W denotes an imaging magnification of the fourth lens group, at the wide angle edge at an infinite object distance.