Optical system and image pickup apparatus

An image pickup apparatus comprising:

• an optical system comprising, in order from an object side to an image side:
• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power configured to move during focusing;
• and
• a third lens unit,
• wherein an interval between each pair of adjacent lens units is changed during focusing,
• wherein the first lens unit comprises a positive lens arranged closest to the object side and an aperture stop,
• wherein the second lens unit consists of one negative lens, and
• wherein the following conditional expressions are satisfied:
• LD/f<1.0;
• 1.58<ndG2N<1.80;
• 55<νdG2N<75;
• and
• 0.534<θgFG2N<0.560
• where LD represents a distance on an optical axis from a lens surface closest to the object side in the optical system to an image plane, f represents a focal length of the optical system, ndG2N represents a refractive index of a material of the one negative lens, vdG2N represents an Abbe number of the material of the one negative lens, and θgFG2N represents a partial dispersion ratio of the material of the one negative lens;
• and
• an image pickup element configured to receive an image formed by the optical system.

An optical system comprising, in order from an object side to an image side:

• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power configured to move during focusing;
• and
• a third lens unit,
• wherein an interval between each pair of adjacent lens units is changed during focusing,
• wherein the first lens unit comprises a positive lens arranged closest to the object side, a plurality of negative lenses and an aperture stop,
• wherein the second lens unit consists of one negative lens, and
• wherein the following conditional expressions are satisfied:
• LD/f<1.0;
• 1.58<ndG2N<1.80;
• 55<νdG2N<75;
• and
• 0.17<dG1PN/f<0.45,
• where LD represents a distance on an optical axis from a lens surface closest to the object side in the optical system to an image plane, f represents a focal length of the optical system, ndG2N represents a refractive index of a material of the one negative lens, νdG2N represents an Abbe number of the material of the one negative lens, and dG1PN represents a distance on the optical axis between the positive lens and a negative lens located closest to the object side of the plurality of negative lenses included in the first lens unit.

An optical system comprising, in order from an object side to an image side:

• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power configured to move during focusing;
• and
• a third lens unit,
• wherein an interval between each pair of adjacent lens units is changed during focusing,
• wherein the first lens unit comprises a positive lens arranged closest to the object side and an aperture stop,
• wherein the second lens unit consists of one negative lens, and
• wherein the following conditional expressions are satisfied:
• LD/f<1.0;
• 1.58<ndG2N<1.80;
• 55<νdG2N<75;
• and
• 0.2<dF2/LD<0.5,
• where LD represents a distance on an optical axis from a lens surface closest to the object side in the optical system to an image plane, f represents a focal length of the optical system, ndG2N represents a refractive index of a material of the one negative lens, νdG2N represents an Abbe number of the material of the one negative lens, and dF2 represents a distance on the optical axis from a lens surface on the image side of the one negative lens to the image plane.

An optical system comprising, in order from an object side to an image side:

• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power configured to move during focusing;
• and
• a third lens unit,
• wherein an interval between each pair of adjacent lens units is changed during focusing,
• wherein the first lens unit comprises a positive lens arranged closest to the object side and an aperture stop arranged closest to the image side in the first lens unit,
• wherein the second lens unit consists of one negative lens, and
• wherein the following conditional expressions are satisfied:
• LD/f<1.0;
• 1.58<ndG2N<1.80;
• and
• 55<νdG2N<75,
• where LD represents a distance on an optical axis from a lens surface closest to the object side in the optical system to an image plane, f represents a focal length of the optical system, ndG2N represents a refractive index of a material of the one negative lens, and νdG2N represents an Abbe number of the material of the one negative lens.