Zoom lens and image pickup apparatus having the same
AssigneeCanon Kabushiki Kaisha
InventorKazuya Shimomura
Life of this patent
Estimating the term…
Abstract
A zoom lens includes, in order from an object side: a negative first lens unit which does not move for zooming; a positive second lens unit which moves during the zooming; a negative third lens unit which moves during the zooming; and a positive fourth lens unit, wherein the following expressions are satisfied: −0.80<f1/f2<−0.25, −1.2<f2/f3<−0.4, and 0.5<|m2/m3|<3.0, where f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, f3 represents a focal length of the third lens unit, m2 represents a moving amount of the second lens unit during the zooming from a wide angle end to a telephoto end, and m3 represents a moving amount of the third lens unit during the zooming from the wide angle end to the telephoto end.
Claims8
A zoom lens comprising, in order from an object side to an image side:
- a first lens unit having a negative refractive power which does not move for zooming;
- a second lens unit having a positive refractive power which moves during the zooming;
- a third lens unit having a negative refractive power which moves during the zooming;
- and
- a fourth lens unit having a positive refractive power, wherein the following expressions are satisfied:
- −0.80<f1/f2<−0.25,
- −1.2<f2/f3<−0.4, and
- 0.5<|m2/m3|<3.0,
- where f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, f3 represents a focal length of the third lens unit, m2 represents a moving amount of the second lens unit during the zooming from a wide angle end to a telephoto end, and m3 represents a moving amount of the third lens unit during the zooming from the wide angle end to the telephoto end.
An image pickup apparatus comprising:
- a zoom lens comprising, in order from an object side to an image side:
- a first lens unit having a negative refractive power which does not move for zooming;
- a second lens unit having a positive refractive power which moves during the zooming;
- a third lens unit having a negative refractive power which moves during the zooming;
- and
- a fourth lens unit having a positive refractive power, wherein the following expressions are satisfied:
- −0.80<f1/f2<−0.25,
- −1.2<f2/f3<−0.4, and
- 0.5<|m2/m3|<3.0,
- where f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, f3 represents a focal length of the third lens unit, m2 represents a moving amount of the second lens unit during the zooming from a wide angle end to a telephoto end, and m3 represents a moving amount of the third lens unit during the zooming from the wide angle end to the telephoto end;
- and
- an image pickup element which photoelectrically converts an optical image formed by the zoom lens.
Dependencies are inferred from the claim text.