Zoom lens, optical apparatus equipped therewith, and method for manufacturing zoom lens

A zoom lens comprising, in order from an object side:

• a first lens group having positive 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,
• the third lens group including, in order from the object side, a first positive lens, a cemented lens constructed by in order from the object side a second positive lens cemented with a negative lens, and a negative meniscus lens, and
• the following conditional expression being satisfied:
• 0.170<(−f2)/f3<0.365
• where f2 denotes a focal length of the second lens group, and f3 denotes a focal length of the third lens group.

A method for manufacturing a zoom lens including, in order from an object side, a first lens group having positive 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, the method comprising steps of:

• disposing, in order from the object side, a first positive lens, a cemented lens constructed by in order from the object side a second positive lens cemented with a negative lens, and a negative meniscus lens into the third lens group;
• disposing the third lens group with satisfying the following conditional expressions:
• r3R<0
• −2.00<(r3R+r3F)/(r3R−r3F)<1.00
• where r3F denotes a radius of curvature of an image side lens surface of the cemented lens in the third lens group, and r3R denotes a radius of curvature of an object side lens surface of the negative meniscus lens in the third lens group;
• and
• disposing each lens group with satisfying the following conditional expression:
• 6.00<f1/ (−f2)<7.80
• where f1 denotes a focal length of the first lens group, and f2 denotes a focal length of the second lens group.

A method for manufacturing a zoom lens including, in order from an object side, a first lens group having positive 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, the method comprising steps of:

• disposing, in order from the object side, a first positive lens, a cemented lens constructed by in order from the object side a second positive lens cemented with a negative lens, and a negative meniscus lens into the third lens group;
• and
• disposing each lens group with satisfying the following conditional expression:
• 0.170<(−f2)/f3<0.365
• where f2 denotes a focal length of the second lens group, and f3 denotes a focal length of the third lens group.