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

An optical system consisting of a preceding lens group having a negative refractive power and a succeeding lens group having a positive refractive power, which are arranged in order from the object side along an optical axis,

• wherein the succeeding lens group comprises a focusing group having a positive refractive power which is arranged to be closest to an object in the succeeding lens group, and an image-side group which is arranged to be closer to an image than the focusing group, and the focusing group moves to an image side along the optical axis upon focusing on a short-distance object from an object at infinity, and
• the following conditional expression is satisfied:
• 1.00<βB/βC<10.00
• where
• βB:
• magnification of the succeeding lens group upon focusing on infinity, and
• βC:
• magnification of the image-side group upon focusing on infinity.

A method for manufacturing an optical system consisting of a preceding lens group having a negative refractive power and a succeeding lens group having a positive refractive power which are arranged in order from an object side along an optical axis,

• the method comprising a step of disposing the lens groups in a lens barrel such that:
• the succeeding lens group comprises a focusing group having a positive refractive power which is arranged to be closest to an object in the succeeding lens group, and an image-side group which is arranged to be closer to an image than the focusing group, and
• the focusing group moves to an image side along the optical axis upon focusing on a short-distance object from an object at infinity,
• the method further comprising any of the following features (A), (B), or (C):
• (A) satisfying the following conditional expressions:
• 0.78<fB/fC<1.00
• 1.20<FNO<3.00
• where
• fB:
• a focal length of the succeeding lens group upon focusing on infinity,
• fC:
• a focal length of the image-side group upon focusing on infinity, and
• FNO:
• F number of the optical system upon focusing on infinity,
• (B) satisfying the following conditional expression:
• 1.00<βB/βC<10.00
• where
• βB:
• magnification of the succeeding lens group upon focusing on infinity, and
• βC:
• magnification of the image-side group upon focusing on infinity,
• (C) arranging an aperture stop in the succeeding lens group, and satisfying the following conditional expressions:
• 0.78</B/fC<1.00
• 0.35<STL/TL<0.70
• where
• EB:
• the focal length of the succeeding lens group upon focusing on infinity,
• fC:
• the focal length of the image-side group upon focusing on infinity,
• STL:
• a distance on the optical axis from the aperture stop to an image surface upon focusing on infinity, and
• TL:
• an entire length of the optical system.

An optical system consisting of a preceding lens group having a negative refractive power and a succeeding lens group having a positive refractive power which are arranged in order from an object side along an optical axis,

• wherein the succeeding lens group comprises a focusing group having a positive refractive power which is arranged to be closest to an object in the succeeding lens group, and an image-side group which is arranged to be closer to an image than the focusing group, and the focusing group moves to an image side along the optical axis upon focusing on a short-distance object from an object at infinity,
• an aperture stop is arranged in the succeeding lens group, and
• the following conditional expressions are satisfied:
• 0.78</B/fC<1.00
• 0.35<STL/TL<0.70
• where
• fB:
• a focal length of the succeeding lens group upon focusing on infinity,
• fC:
• a focal length of the image-side group upon focusing on infinity,
• STL:
• a distance on the optical axis from the aperture stop to an image surface upon focusing on infinity, and
• TL:
• an entire length of the optical system.