Optical system and image pickup apparatus having the same including five lens units of +−++− or +−−+− refractive powers
AssigneeCanon Kabushiki Kaisha
InventorShunji Iwamoto
Life of this patent
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Abstract
An optical system includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive or negative refractive power, a fourth lens unit having positive refractive power, and a fifth lens unit having negative refractive power. During focusing from infinity to the shortest distance, the second lens unit and the fourth lens unit move, the first lens unit, the third lens unit, and the fifth lens unit do not move. A predetermined condition is satisfied.
Claims17
An optical system comprising, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive or negative refractive power, a fourth lens unit having positive refractive power, and a fifth lens unit having negative refractive power,
- wherein during focusing from infinity to the shortest distance, the second lens unit and the fourth lens unit move, the first lens unit, the third lens unit, and the fifth lens unit do not move, and
- wherein the following inequalities are satisfied:
- 0.10<sk/f<0.25
- 0.010<f/|f3|<0.500
- −3.50<f/f5<−0.80
- −1.6<f/f2<−0.3
- where sk is a distance on an optical axis from a lens surface closest to an image plane of the optical system to the image plane, f is a focal length of the optical system in an in-focus state at infinity, and f3 is a focal length of the third lens unit, f5 is a focal length of the fifth lens unit, and f2 is a focal length of the second lens unit.
The image pickup apparatus comprising:
- an optical system;
- and
- an image sensor configured to receive an image formed by the optical system,
- wherein the optical system includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive or negative refractive power, a fourth lens unit having positive refractive power, and a fifth lens unit having negative refractive power,
- wherein during focusing from infinity to the shortest distance, the second lens unit and the fourth lens unit move, the first lens unit, the third lens unit, and the fifth lens unit do not move, and
- wherein the following inequalities are satisfied:
- 0.10<sk/f<0.25
- 0.010<f/|f3|<0.500
- −3.50<f/f5<−0.80
- −1.6<f/f2<−0.3
- where sk is a distance on an optical axis from a lens surface closest to an image plane of the optical system to the image plane, f is a focal length of the optical system in an in-focus state at infinity, and f3 is a focal length of the third lens unit, f5 is a focal length of the fifth lens unit, and f2 is a focal length of the second lens unit.
Dependencies are inferred from the claim text.