Zoom lens and image pickup apparatus including the same
AssigneeCanon Kabushiki Kaisha
InventorShoichi Takemoto
Life of this patent
Estimating the term…
Abstract
A zoom lens includes, 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; a third lens unit having a positive refractive power that moves during zooming; and at least one lens unit having a positive refractive power, and focal lengths of the zoom lens at a wide angle end and a telephoto end, a maximum value of a half angle of field at the wide angle end, and products of lateral magnifications of lens units arranged on the image side of the third lens unit in a state in which focus is at infinity at the telephoto end and the wide angle end are appropriately set.
Claims8
A zoom lens, 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;
- a third lens unit having a positive refractive power that moves during zooming;
- and
- at least one lens unit having a positive refractive power,
- wherein the following conditions are satisfied:
- 0.02<LN(|βct/βcw|)/LN(ft/fw)<0.50
- 2.0<ft/f1<7.0
- 20<ft/(fw×tan ωw)<120
- where fw and ft represent focal lengths of the zoom lens at a wide angle end and a telephoto end, respectively, ωw represents a maximum value of a half angle of field at the wide angle end, βct and βcw represent products of lateral magnifications of lens units arranged on the image side of the third lens unit in a state in which focus is at infinity at the telephoto end and the wide angle end, respectively, and LN( ) in the conditional expression represents a natural logarithm of a numerical value in parentheses.
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 positive refractive power that does not move for zooming;
- a second lens unit having a negative refractive power that moves during zooming;
- a third lens unit having a positive refractive power that moves during zooming;
- and
- at least one lens unit having a positive refractive power,
- wherein the following conditions are satisfied:
- 0.02<LN(|βct/βw|)/LN(ft/fw)<0.50
- 2.0<ft/f1<7.0
- 20<ft/(fw×tan ωw)<120
- where fw and ft represent focal lengths of the zoom lens at a wide angle end and a telephoto end, respectively, ωw represents a maximum value of a half angle of field at the wide angle end, βct and βcw represent products of lateral magnifications of lens units arranged on the image side of the third lens unit in a state in which focus is at infinity at the telephoto end and the wide angle end, respectively, and LN( ) in the conditional expression represents a natural logarithm of a numerical value in parentheses;
- and
- an image pickup element.
Dependencies are inferred from the claim text.