Optical system, optical apparatus and method for manufacturing the optical system

A method for manufacturing an optical system having, in order from an object, a first lens group having negative refractive power and a second lens group,

• the first lens group including, in order from the object, a first negative lens and a second negative lens having a concave surface facing the object, the method comprising:
• assembling each lens in a lens barrel such that the following conditional expression is satisfied:
• 7.94≦(−fn12)/f<48.00
• where fn12 denotes a focal length of the second negative lens, and f denotes a focal length of the entire optical system.

An optical system, comprising in order from an object:

• a first lens group having negative refractive power;
• and
• a second lens group,
• the first lens group including, in order from the object, a first lens having negative refractive power, a second lens which has a concave surface facing the object and has negative refractive power, and a third lens, and
• the following conditional expression being satisfied:
• −23.0<νd3−νd2<24.2
• where νd3 denotes an Abbe number of the third lens with respect to d-line, and νd2 denotes an Abbe number of the second lens with respect to d-line.

A method for manufacturing an optical system having, in order from an object, a first lens group having negative refractive power and a second lens group,

• the first lens group including, in order from the object, a first lens having negative refractive power, a second lens which has a concave surface facing the object and has negative refractive power, and a third lens, the method comprising:
• assembling each lens in a lens barrel such that the following conditional expression is satisfied:
• −23.0<νd3−νd2<24.2
• where νd3 denotes an Abbe number of the third lens with respect to d-line, and νd2 denotes an Abbe number of the second lens with respect to d-line.