Patent ID: 8144401

Claim:
A zoom lens, comprising: a first lens group disposed between a magnified side and a reduced side and having a negative refractive power, the first lens group comprising a first lens, a second lens, and a third lens arranged in sequence from the magnified side to the reduced side, wherein refractive powers of the first lens, the second lens, and the third lens are respectively positive, negative, and negative; a second lens group disposed between the first lens group and the reduced side and having a positive refractive power, the second lens group comprising a fourth lens and a fifth lens arranged in sequence from the magnified side to the reduced side, wherein refractive powers of the fourth lens and the fifth lens are respectively negative and positive; a third lens group disposed between the second lens group and the reduced side and having a positive refractive power, the third lens group comprising a sixth lens, wherein a refractive power of the sixth lens is positive; and a fourth lens group disposed between the third lens group and the reduced side and having a positive refractive power, the fourth lens group comprising a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, and a thirteenth lens arranged in sequence from the magnified side to the reduced side, wherein refractive powers of the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, and the thirteenth lens are respectively positive, negative, negative, positive, negative, positive, and positive.