Zoom lens and image pickup apparatus including the same
AssigneeCanon Kabushiki Kaisha
InventorHirofumi Abe
Life of this patent
Estimating the term…
Abstract
Provided is a zoom lens, comprising, in order from an object side to an image side: first to fifth lens units having positive, negative, positive, positive, and negative refractive powers, respectively. During zooming, the first, third, and fifth lens units are immovable, and the second and fourth lens units are moved. The fifth lens unit includes a partial unit (L5n) having a negative refractive power, and a partial unit (L5p) having a positive refractive power. An entire lens length (TL), a focal length (ft) of an entire system at a telephoto end, a focal length (f2) of the second lens unit, a focal length (f4) of the fourth lens unit, and a focal length (f5n) of the partial unit (L5n) are set appropriately.
Claims7
A zoom lens, 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;
- a third lens unit having a positive refractive power;
- a fourth lens unit having a positive refractive power;
- and
- a fifth lens unit having a negative refractive power,
- during zooming, the first lens unit, the third lens unit, and the fifth lens unit being immovable, and the second lens unit and the fourth lens unit being moved,
- wherein the fifth lens unit comprises a partial unit having a negative refractive power and a partial unit having a positive refractive power in order from the object side to the image side with a widest air gap in the fifth lens unit as a boundary, and the following conditional expressions are satisfied:
- 1.70<ft/TL<2.50;
- 23<ft/|f2|<100;
- and
- 1.0<f4/|f5n|<5.0
- where TL represents an entire lens length, ft represents a focal length of an entire system at a telephoto end, f2 represents a focal length of the second lens unit, f4 represents a focal length of the fourth lens unit, and f5n represents a focal length of the partial unit having the negative refractive power.
An image pickup apparatus, comprising:
- a zoom lens;
- and
- an image pickup element configured to receive an image formed by the zoom lens,
- wherein the zoom lens comprises, 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;
- a third lens unit having a positive refractive power;
- a fourth lens unit having a positive refractive power;
- and
- a fifth lens unit having a negative refractive power,
- wherein during zooming, the first lens unit, the third lens unit, and the fifth lens unit are immovable, and the second lens unit and the fourth lens unit are moved, and
- wherein the fifth lens unit comprises a partial unit having a negative refractive power, and a partial unit having a positive refractive power in order from the object side to the image side with a widest air gap in the fifth lens unit as a boundary, and the following conditional expressions are satisfied:
- 1.70<ft/TL<2.50;
- 23<ft/|f2|<100;
- and
- 1.0<f4/|f5n|<5.0
- where TL represents an entire lens length, ft represents a focal length of an entire system at a telephoto end, f2 represents a focal length of the second lens unit, f4 represents a focal length of the fourth lens unit, and f5n represents a focal length of the partial unit having the negative refractive power.
Dependencies are inferred from the claim text.