Zoom lens of rear focus type
AssigneeCanon Kabushiki Kaisha
InventorsHiroyuki Hamano, Hiroshi Satoh
Life of this patent
Estimating the term…
Abstract
A zoom lens of the rear focus type is disclosed, comprising, in the order from the object 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 zooming is performed by moving the second and fourth lens units, and focusing is performed by moving the fourth lens unit.
Claims12
A zoom lens comprising:
- in the order from an object 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 zooming from a wide-angle end to a telephoto end is performed by moving said second lens unit and said fourth lens unit, and
- wherein said zoom lens satisfies the following condition:
- 1.09<.beta..sub.5 <1.45
- wherein .beta..sub.5 is the lateral magnification of said fifth lens unit with an object at infinity.
A zoom lens comprising, in the order from an object 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 zooming from a wide-angle end to a telephoto end is performed by moving said second lens unit and said fourth lens unit, and
- wherein said first lens unit, said third lens unit and said fifth lens nit are stationary, and
- wherein said zoom lens satisfies the following conditions:
- 0. 8<.vertline.f.sub.5 /f.sub.3 .vertline.<2.1
- where f.sub.3 and f.sub.5 are the focal lengths of said third and fifth lens units, respectively.
A zoom lens comprising, in the order from an object 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 zooming from a wide-angle end to a telephoto end is performed by moving said second lens unit and said fourth lens unit, and
- wherein said first lens unit, said third lens unit and said fifth lens unit are stationary, and
- wherein said zoom lens satisfies the following condition:
- 0.5<f.sub.3 /f.sub.4 <1.2
- where if is the focal length of the i-th lens unit.
Dependencies are inferred from the claim text.