Zoom lens system and image pickup apparatus including the same
AssigneeCanon Kabushiki Kaisha
InventorsHiroshi Endo, Kenji Obu
Life of this patent
Estimating the term…
Abstract
At least one exemplary embodiment is directed to a zoom lens system having a telephoto-type configuration at the telephoto end. When assuming that an Abbe number is vd, and a partial dispersion ratio is θgF, this zoom lens system includes a refractive optical element having positive refracting power made up of a solid material that can satisfy the following conditions: −2.100×10−3·vd+0.693<θgF 0.555<θgF<0.9 Thus, facilitating the configuration of a zoom lens system capable of appropriately correcting and/or reducing various aberrations, including a chromatic aberration straddling the entire zoom area.
Claims23
A zoom lens system comprising:
- a refractive optical element having positive refracting power, which is made up of a solid material;
- wherein the Abbe number vd and partial dispersion ratio θgF of the solid material satisfies the following conditions
- −2.100×10−3·vd+0.693<θgF
- 0.555<θgF<0.9;
- and
- wherein with the zoom lens, the maximum value at the telephoto end of the height, from the optical axis, of a paraxial marginal ray passing through the lens surface further forward than the intersection between the optical axis and a paraxial chief ray is greater than the maximum value at the telephoto end of the height, from the optical axis, of the paraxial marginal ray passing through the lens surface backward from the intersection.
A zoom lens system comprising in order from forwards to backwards:
- a first lens unit having positive optical power;
- a second lens unit having negative optical power;
- and
- a rear lens component having positive optical power as a whole;
- wherein with the zoom lens system, the interval between the first lens unit and the second lens unit, and the interval between the second lens unit and rear lens component are changed at the time of zooming;
- and
- wherein the first lens unit comprises a refractive optical element having positive refracting power made up of a solid material, and the Abbe number vd and partial dispersion ratio θgF of the solid material satisfies the following conditions.
- −2.100×10−3·vd+0.693<θgF
- 0.555<θgF<0.9.
A zoom lens system comprising in order from the object side to the image side:
- a first lens unit having positive optical power;
- a second lens unit having negative optical power;
- and
- a rear lens component having positive optical power as a whole, which includes an aperture stop, and a lens unit having positive optical power disposed backward from the aperture stop;
- wherein with the zoom lens system, the interval between the first lens unit and the second lens unit, and the interval between the second lens unit and rear lens component are changed at the time of zooming;
- and
- wherein the lens unit having positive optical power disposed backward from the aperture stop comprises a refractive optical element having positive refracting power made up of a solid material, and the Abbe number vd and partial dispersion ratio θgF of the solid material satisfies the following conditions
- −2.100×10−3·vd+0.693<θgF
- 0.555<θgF<0.9.
Dependencies are inferred from the claim text.