Zoom lens system, optical apparatus and method for manufacturing zoom lens system

A method for manufacturing a zoom lens system including, in order from an object along an optical axis, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power, the method comprising steps of:

• disposing an aperture stop to an image side of the second lens group;
• disposing the first lens group, the second lens group, the third lens group, the fourth lens group and the fifth lens group such that upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group increases, a distance between the second lens group and the third lens group decreases, a distance between the third lens group and the fourth lens group varies, and a distance between the fourth lens group and the fifth lens group varies, and
• satisfying the following conditional expressions:
• 0.17<f1/fT<0.60
• 1.03<φT/φW<1.70
• 1.00≦φM5/φW<1.40
• where fT denotes a focal length of the zoom lens system in the telephoto end state, f1 denotes a focal length of the first lens group, φW denotes the maximum diameter of the aperture stop in the wide-angle end state, φT denotes the maximum diameter of the aperture stop in the telephoto end state, and φM5 denotes the maximum diameter of the aperture stop in an intermediate focal length state, in which the intermediate focal length of the zoom lens system is five times or more and eight times of fW or less when fW denotes a focal length of the zoom lens system in the wide-angle end state.

A zoom lens system comprising, in order from an object side along an optical axis:

• a first lens group having positive refractive power;
• a second lens group having negative refractive power;
• a third lens group having positive refractive power;
• a fourth lens group having negative refractive power;
• and
• a fifth lens group having positive refractive power,
• an aperture stop being disposed to an image side of the second lens group,
• upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group increasing, a distance between the second lens group and the third lens group decreasing, a distance between the third lens group and the fourth lens group varying, and a distance between the fourth lens group and the fifth lens group varying, and
• the following conditional expressions being satisfied:
• 0.17<f1/fT<0.60
• 1.03<φT/φW<1.70
• 1.02<φM10/φW<1.70
• where fT denotes a focal length of the zoom lens system in the telephoto end state, f1 denotes a focal length of the first lens group, φW denotes the maximum diameter of the aperture stop in the wide-angle end state, φT denotes the maximum diameter of the aperture stop in the telephoto end state, and φM10 denotes the maximum diameter of the aperture stop in an intermediate focal length state, in which the intermediate focal length of the zoom lens system is ten times of fW or more when fW denotes a focal length of the zoom lens system in the wide-angle end state.

A method for manufacturing a zoom lens system including, in order from an object along an optical axis, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power, the method comprising steps of:

• disposing an aperture stop to an image side of the second lens group;
• disposing the first lens group, the second lens group, the third lens group, the fourth lens group and the fifth lens group such that upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group increases, a distance between the second lens group and the third lens group decreases, a distance between the third lens group and the fourth lens group varies, and a distance between the fourth lens group and the fifth lens group varies, and
• satisfying the following conditional expressions:
• 0.17<f1/fT<0.60
• 1.03<φT/φW<1.70
• 1.02<φM10/φW<1.70
• where fT denotes a focal length of the zoom lens system in the telephoto end state, f1 denotes a focal length of the first lens group, φW denotes the maximum diameter of the aperture stop in the wide-angle end state, φT denotes the maximum diameter of the aperture stop in the telephoto end state, and φM10 denotes the maximum diameter of the aperture stop in an intermediate focal length state, in which the intermediate focal length of the zoom lens system is ten times of fW or more when fW denotes a focal length of the zoom lens system in the wide-angle end state.