Zoom lens
AssigneeCanon Kabushiki Kaisha
InventorsTakeshi Nishimura, Yoshinori Itoh
Life of this patent
Estimating the term…
Abstract
A zoom lens which includes, in order from an object side, a first lens unit of positive refractive power, a second lens unit of positive refractive power and a third lens unit of negative refractive power, wherein the first, second and third lens units are moved such that, during zooming from a wide-angle end to a telephoto end, a separation between the first lens unit and the second lens unit increases and a separation between the second lens unit and the third lens unit decreases, and wherein the zoom lens has a diffractive optical element.
Claims24
A zoom lens system comprising a plurality of movable lens units which consist of, in order from an object side to an image side,
- a first lens unit of positive refractive power, and
- a second lens unit of negative refractive power,
- wherein a separation between said first lens unit and said second lens unit is varied to effect zooming, and wherein said first lens unit includes at least three lenses and said zoom lens system has a diffractive part.
A zoom lens system comprising a plurality of movable lens units which consists of, in order from an object side to an image side,
- a first lens unit of positive refractive power and
- a second lens unit of negative refractive power,
- wherein a separation between said first lens unit and said second lens unit is varied to effect zooming, and wherein said first lens unit has two positive lenses and two negative lenses and said zoom lens system has a diffractive part.
A zoom lens system comprising a plurality of lens units which consist of, in order from an object side to an image side,
- a first lens unit of positive refractive power and
- a second lens unit of negative refractive power,
- wherein a separation between said first lens unit and said second lens unit is varied to effect zooming, and wherein said first lens unit has one positive lens and two negative lenses, and said zoom lens system has a diffractive part.
Dependencies are inferred from the claim text.