Zoom lens and photographic apparatus having the same
AssigneeCanon Kabushiki Kaisha
InventorsFumihito Wachi, Kenichi Kimura
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 of negative refractive power, the first lens unit having an aspherical lens of negative refractive power, a stop, a second lens unit of positive refractive power, the second lens unit having an aspherical lens of positive refractive power, and a third lens unit of positive refractive power, wherein, during zooming from a wide-angle end to a telephoto end, the second lens unit and the stop move in unison toward the object side, and the first lens unit so moves as to compensate for a shift of an image plane resulting from the zooming.
Claims31
A zoom lens comprising, in order from an object side to an image side:
- a first lens unit of negative optical power, said first lens unit having an aspherical lens of negative optical power;
- a stop;
- a second lens unit of positive optical power, said second lens unit having an aspherical lens of positive optical power;
- and
- a third lens unit of positive optical power,
- wherein, during a variation in magnification from a wide-angle end to a telephoto end, said second lens unit and said stop move in unison toward the object side, and said first lens unit so moves as to compensate for a shift of an image plane resulting from the variation in magnification,
- wherein said first lens unit is located closest to the object side among all of the lens units, and said second lens unit consists of two positive lens elements and one negative lens element.
A zoom lens comprising, in order from an object side to an image side;
- a first lens unit of negative optical power, said first lens unit having, in order from the object side to the image side, a negative lens of meniscus form convex toward the object side, a negative lens of meniscus form convex toward the object side, and a positive lens of meniscus form convex toward the object side;
- a second lens unit of positive optical power;
- and
- a third lens unit of positive optical power,
- wherein, during a variation in magnification from a wide-angle end to a telephoto end, said second lens unit moves toward the object side and said first lens unit so moves as to compensate for a shift of an image plane resulting from the variation in magnification, and
- wherein each of said first lens unit and said second lens unit has at least one aspherical lens,
- said zoom lens satisfying the following conditions:
- −3≦f1/fw≦−2
- 2≦f2/fw≦3
- where f1 is a focal length of said first lens unit, f2 is a focal length of said second lens unit, and fw is a focal length of said zoom lens at the wide-angle end, and
- wherein said first lens unit is located closest to the object side among all of the lens units.
A zoom lens comprising, in order from an object side to an image side:
- a first lens unit of negative optical power, said first lens unit consisting of, in order from the object side to the image side, a negative lens, a negative lens and a positive lens;
- a second lens unit of positive optical power, said second lens unit having, in order from the object side to the image side, a positive lens, a negative lens and a positive lens;
- and
- a third lens unit of positive optical power,
- wherein a variation in magnification is effected by varying a separation between said first lens unit and said second lens unit,
- wherein said first lens unit is located closest to the object side among all of the lens units.
A zoom lens comprising, in order from an object side to an image side:
- a first lens unit of negative optical power, said first lens unit having, in order from the object side to the image side, a negative lens having a concave surface facing the image side and a positive lens;
- a stop:
- a second lens unit of positive optical power, said second lens unit consisting of, in order from the object side to the image side, a positive lens, a negative lens and a positive lens;
- and
- a third lens unit of positive optical power,
- wherein a variation in magnification is effected by varying a separation between said first lens unit and said second lens unit,
- said first lens unit is located closest to the object side among all of the lens units.
A photographing apparatus comprising a zoom lens according to any of claims 1 to 26 and 28 to 31, and an image pickup element which receives light from said zoom lens.
A zoom lens comprising in order from an object side to an image side:
- a first lens unit of negative optical power, said first lens unit being located closest to the object side among all lens units,
- a stop,
- a second lens unit of positive optical power, said second lens unit consisting of two positive lens elements and one negative lens element,
- a third lens unit of positive optical power,
- wherein spacing between said first lens unit and said second is varied for varying magnification, and
- at least one aspherical lens.
A zoom lens comprising in order from an object side to an image side,
- a first lens unit of negative optical power, said first lens unit having negative lens, a negative lens and a positive lens, and being located closest to the object side among all lens units,
- a stop,
- a second lens unit of positive optical power, said second lens unit consisting of, in order from the object side to the image side, a positive lens, a negative lens, and a positive lens, and
- a third lens unit of positive optical power,
- wherein a spacing between said first lens unit and said second lens unit is varied for varying magnification.
A zoom lens comprising in order from an object side to an image side,
- a first lens unit of negative optical power, said first lens unit having in order from the object side to the image side a negative lens, a negative lens and a positive lens, and being located closest to the object side among all lens units,
- a second lens unit of positive optical power, said second lens unit consisting of, in order from the object side to the image side, a positive lens, a negative lens and a positive lens, and
- a third lens unit of positive optical power,
- wherein a space between said first lens unit and said second lens unit is varied for varying magnification, and
- at least one aspherical lens.
A zoom lens comprising in order from an object side to an image side,
- a first lens unit of negative optical power, said first lens unit having in order from the object side to the image side a negative lens having a convex surface facing toward the image side, and a positive lens, and said first lens unit being located closest to the object side among all lens units,
- a second lens unit of positive optical power, said second lens unit consisting of, in order from the object side to the image side a positive lens, a negative lens, and a positive lens,
- a third lens unit of positive optical power,
- wherein the spacing between said first lens unit and said second lens unit is varied for varying magnification, and
- at least one aspherical lens.
Dependencies are inferred from the claim text.