Patent ID: 7411741

Claim:
A zoom lens system comprising, in order from an object side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; a third lens unit having a positive refractive power; a fourth lens unit having a positive refractive power; and an aperture stop disposed between the second lens unit and the third lens unit, during zooming from a wide-angle end to a telephoto end, each space between the lens units which are arranged adjacent to each other being changed, the first lens unit comprising, in order from the object side, a negative lens as a single lens having a negative refractive power, a reflective optical element having a reflective surface which reflects an optical path, and a sub unit having a positive refractive power, the following conditions (1), (2) and (3) being satisfied: n dL1 >1.95 (1); v dL1 <26 (2); and 0.5 <D 13 /f 1 <1.5 (3), in which n dL1 is a refractive index of the negative lens of the first lens unit closest to the object side for the d-line, v dL1 is the Abbe number of the negative lens of the first lens unit closest to the object side, D 13 is a distance along an optical axis between an image-side surface of the negative lens of the first lens unit closest to the object side and an object-side surface of the sub unit having the positive refractive power, and f 1 is a focal length of the first lens unit.