Optical system and imaging apparatus including the same
AssigneeCanon Kabushiki Kaisha
InventorsShinichiro Saito, Makoto Nakahara, Suguru Inoue, Akira Mizuma, Masakazu Yamagishi
Life of this patent
Estimating the term…
Abstract
An optical system includes a first lens unit B1 having a positive refractive power, a second lens unit B2, and a third lens unit B3 disposed in order from an object side to an image side. The second lens unit B2 moves in focusing so that an interval between adjacent lens units among the first, second, and third lens units changes. The first lens unit B1 includes a positive lens G1p disposed closest to the object side and a negative lens G1n being a closest negative lens with respect to the object side. The optical system satisfies a predetermined condition.
Claims15
An optical system comprising:
- a first lens unit having a positive refractive power;
- a second lens unit;
- and
- a third lens unit disposed in order from an object side to an image side, the second lens unit configured to move in focusing so that an interval between adjacent lens units among the first, second, and third lens units changes,
- wherein the first lens unit includes a positive lens G1p disposed closest to the object side and a negative lens G1n being a closest negative lens with respect to the object side, and
- wherein the following conditional expressions are satisfied:
- 0.02<BF/fG1p<0.14
- 2.00<|fG1p/fG1n|<10.00
- 20.0<νdG1n<40.0
- −0.1000<θgFG1n−(−1.665×10−7×νdG1n3+5.213×10−5×νdG1n2−5.656×10−3×νdG1n+0.7268)<−0.0010
- where BF is a back focus of the optical system, fG1p is a focal length of the positive lens G1p, fG1n is a focal length of the negative lens G1n, νdG1n is an Abbe number of a material of the negative lens G1n, and θgFG1n is a partial dispersion ratio of the negative lens G1n.
An imaging apparatus comprising:
- an optical system;
- and
- an image sensor configured to receive light of an image formed by the optical system,
- wherein the optical system includes a first lens unit having a positive refractive power, a second lens unit, and a third lens unit disposed in order from an object side to an image side,
- wherein the second lens unit moves in focusing so that an interval between adjacent lens units among the first, second, and third lens units changes,
- wherein the first lens unit includes a positive lens G1p disposed closest to the object side and a negative lens G1n being a closest negative lens with respect to the object side, and
- wherein the following conditional expressions are satisfied:
- 0.02<BF/fG1p<0.14
- 2.00<|fG1p/fG1n|<10.00
- 20.0<νdG1n<40.0
- −0.1000<θgFG1n−(−1.665×10−7×νdG1n3+5.213×10−5×νdG1n2−5.656×10−3×νdG1n+0.7268)<−0.0010
- where BF is a back focus of the optical system, fG1p is a focal length of the positive lens G1p, fG1n is a focal length of the negative lens G1n, νdG1n is an Abbe number of a material of the negative lens G1n, and θgFG1n is a partial dispersion ratio of the negative lens G1n.
Dependencies are inferred from the claim text.