Zoom lens system
AssigneeCanon Kabushiki Kaisha
InventorMasaru Sakamoto
Life of this patent
Estimating the term…
Abstract
A zoom lens system including, in order from an object side to an image side, a first lens unit having a positive refractive power that does not move for zooming, a second lens unit having a negative refractive power that moves during zooming, and a third lens unit having a positive refractive power that moves during zooming. In the zoom lens system, a distance between lens units that are adjacent to each other changes during zooming, the first lens unit includes a first a-lens unit that does not move for focusing, and a first b-lens unit that moves from the image side towards the object side during focusing from an infinite object to a near object, and the first a-lens unit comprises two positive lenses and two negative lenses.
Claims8
A zoom lens system comprising:
- in order from an object side to an image side,
- a first lens unit having a positive refractive power that does not move for zooming;
- a second lens unit having a negative refractive power that moves during zooming;
- and
- a third lens unit having a positive refractive power that moves during zooming, wherein
- a distance between lens units that are adjacent to each other changes during zooming,
- the first lens unit consisting of a first a-lens unit that does not move for focusing, and a first b-lens unit that moves from the image side towards the object side during focusing from an infinite object to a near object, and
- the first a-lens unit comprises two positive lenses and two negative lenses,
- wherein
- the following condition is satisfied:
- 7.50<|f1/f2|<11.00,
- where f1 is a focal length of the first lens unit, and f2 is a focal length of the second lens unit.
An image capturing apparatus comprising:
- a zoom lens system;
- and
- a solid-state image pick up element that photo receives an image formed by the zoom lens system,
- wherein
- the zoom lens system comprises
- in order from an object side to an image side,
- a first lens unit having a positive refractive power that does not move for zooming,
- a second lens unit having a negative refractive power that moves during zooming, and
- a third lens unit having a positive refractive power that moves during zooming,
- wherein
- a distance between lens units that are adjacent to each other changes during zooming,
- the first lens unit consisting of a first a-lens unit that does not move for focusing, and a first b-lens unit that moves from the image side towards the object side during focusing from an infinite object to a near object, and
- the first a-lens unit comprises two positive lenses and two negative lenses
- wherein
- the following condition is satisfied:
- 7.50<|f1/f2|<11.00,
- where f1 is a focal length of the first lens unit, and f2 is a focal length of the second lens unit.
Dependencies are inferred from the claim text.