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US-12619056-B2 - Zoom lens, and image pickup apparatus having the same

US12619056B2US 12619056 B2US12619056 B2US 12619056B2US-12619056-B2

Abstract

A zoom lens includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, a fourth lens unit having positive refractive power, and a fifth lens unit having negative refractive power. During zooming from a wide-angle end to a telephoto end, a distance between adjacent lens units changes, the first lens unit and the third lens unit are fixed, and the second lens unit and the fourth lens unit move. The third lens unit includes a negative lens and a positive lens. A predetermined condition is satisfied.

Inventors

  • Junya Ichimura

Assignees

  • CANON KABUSHIKI KAISHA

Dates

Publication Date
20260505
Application Date
20230612
Priority Date
20220615

Claims (17)

  1. 1 . A zoom lens comprising, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, a fourth lens unit having positive refractive power, and a fifth lens unit having negative refractive power, wherein during zooming from a wide-angle end to a telephoto end, a distance between adjacent lens units changes, the first lens unit and the third lens unit are fixed, and the second lens unit and the fourth lens unit move, wherein the third lens unit includes a negative lens and a positive lens, and wherein the following inequalities are satisfied: −3.50<β3 w/β 3 t<− 0.10 −10.0< f 1/ f 2<−4.0 1.2< f 3/ f 4<2.0 −6.0< M 2/ M 4<−1.5 0.8< M 2/ D 1<2.0 where β3w is a lateral magnification of the third lens unit at the wide-angle end, β3t is a lateral magnification of the third lens unit at the telephoto end, f1 is a focal length of the first lens unit, f2 is a focal length of the second lens unit, f3 is a focal length of the third lens unit, f4 is a focal length of the fourth lens unit, M2 is a moving amount of the second lens unit during zooming from the wide-angle end to the telephoto end, M4 is a moving amount of the fourth lens unit during zooming from the wide-angle end to the telephoto end, and D1 is a distance on an optical axis from a lens surface closest to an object in the first lens unit to a lens surface closest to an image plane in the first lens unit.
  2. 2 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: 0.2 <BF/fw< 1.2 where BF is an air conversion length of a distance on an optical axis from a lens surface closest to an image plane to the image plane at the wide-angle end of the zoom lens, and fw is a focal length of the zoom lens at the wide-angle end.
  3. 3 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: 2.0< f 1 /fw< 12.0 where fw is a focal length of the zoom lens at the wide-angle end.
  4. 4 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: −0.8< f 2/ f 4<−0.3 where f4 is a focal length of the fourth lens unit.
  5. 5 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: 1.5< f 5/ f 2<10.0 where f5 is a focal length of the fifth lens unit.
  6. 6 . The zoom lens according to claim 1 , wherein the third lens unit includes an image stabilizing subunit configured to move in a direction having a component in a direction orthogonal to an optical axis during image stabilization, and wherein the following inequality is satisfied: 1.2< fis/f 3<2.0 where fis is a focal length of the image stabilizing subunit, and f3 is a focal length of the third lens unit.
  7. 7 . The zoom lens according to claim 1 , wherein the third lens unit consists of, in order from the object side to the image side, a first subunit having positive refractive power, a second subunit having positive refractive power, and a third subunit having negative refractive power, wherein the second subunit is a cemented lens of a negative lens and a positive lens arranged in order from the object side to the image side, and wherein the second subunit moves in a direction having a component in a direction orthogonal to an optical axis during image stabilization.
  8. 8 . The zoom lens according to claim 1 , wherein the fifth lens unit includes a positive lens, and wherein the following inequality is satisfied: −0.00163×ν d+ 0.65800<θ gf<− 0.00163×ν d+ 0.7500 where θgf is a partial dispersion ratio of the positive lens of the fifth lens unit for g-line and f-line, and νd is an Abbe number of the positive lens of the fifth lens unit based on d-line.
  9. 9 . The zoom lens according to claim 8 , wherein the positive lens included in the fifth lens unit has a meniscus shape convex to the image side, and the following inequality is satisfied: 15.0<ν d< 24.2.
  10. 10 . The zoom lens according to claim 1 , wherein the zoom lens consists of, in order from the object side to the image side, the first lens unit, the second lens unit, the third lens unit, the fourth lens unit, and the fifth lens unit.
  11. 11 . The zoom lens according to claim 1 , wherein the first lens unit consists of, in order from the object side to the image side, a cemented lens of a negative lens and a positive lens, and a positive lens.
  12. 12 . The zoom lens according to claim 1 , wherein the second lens unit consists of four lenses or less.
  13. 13 . The zoom lens according to claim 12 , wherein the second lens unit consists of, in order from the object side to the image side, a negative lens, a negative lens, a positive lens, and a negative lens.
  14. 14 . The zoom lens according to claim 1 , wherein the third lens unit includes an aperture stop.
  15. 15 . The zoom lens according to claim 1 , wherein the fourth lens unit consists of three or four lenses.
  16. 16 . The zoom lens according to claim 15 , wherein the fourth lens unit consists of, in order from the object side to the image side, a positive lens, a positive lens, a negative lens, and a positive lens.
  17. 17 . An image pickup apparatus comprising: a zoom lens; and an image sensor configured to receive an image formed by the zoom lens, wherein the zoom lens includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, a fourth lens unit having positive refractive power, and a fifth lens unit having negative refractive power, wherein during zooming from a wide-angle end to a telephoto end, a distance between adjacent lens units changes, the first lens unit and the third lens unit are fixed, and the second lens unit and the fourth lens unit move, wherein the third lens unit includes a negative lens and a positive lens, and wherein the following inequalities are satisfied: −3.50<β3 w/β 3 t<− 0.10 −10.0< f 1/ f 2<−4.0 1.2< f 3/ f 4<2.0 −6.0< M 2/ M 4<−1.5 0.8< M 2/ D 1<2.0 where β3w is a lateral magnification of the third lens unit at the wide-angle end, β3t is a lateral magnification of the third lens unit at the telephoto end, f1 is a focal length of the first lens unit, f2 is a focal length of the second lens unit, f3 is a focal length of the third lens unit, f4 is a focal length of the fourth lens unit, M2 is a moving amount of the second lens unit during zooming from the wide-angle end to the telephoto end, M4 is a moving amount of the fourth lens unit during zooming from the wide-angle end to the telephoto end, and D1 is a distance on an optical axis from a lens surface closest to an object in the first lens unit to a lens surface closest to an image plane in the first lens unit.

Description

BACKGROUND Technical Field One of the aspects of the disclosure relates to a zoom lens, and more particularly to a zoom lens suitable for an image pickup apparatus, such as a digital video camera, a digital still camera, a broadcasting camera, a film-based camera, a surveillance camera, and the like. Description of Related Art An overall length fixed type zoom lens is known in which the overall lens length does not change during zooming. Such a zoom lens is suitable to capture a moving image and the like because the center of gravity little changes during zooming. Recently, zoom lenses are demanded to have a high zoom magnification and high optical performance over an overall zoom range for moving image applications. Each of Japanese Patent Laid-Open No. 8-327903 and PCT International Publication No. 2018/074413 discloses, as the overall length fixed type zoom lens, a zoom lens that consists of a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, a fourth lens unit having positive refractive power, and a fifth lens unit having negative refractive power. The zoom lens disclosed in each of Japanese Patent Laid-Open No. 8-327903 and PCT International Publication No. 2018/074413 is configured such that the second lens unit and the fourth lens unit move during zooming. The zoom lens disclosed in Japanese Patent Laid-Open No. 8-327903 is excellent in the small number of lens units that move during zooming and focusing, but higher optical performance is demanded along with the recent high resolution trend of sensors. The zoom lens disclosed in PCT International Publication No. 2018/074413 has high optical performance over the overall zoom range by increasing the number of lenses in each lens unit, but is demanded to have a higher zoom magnification. SUMMARY One of the aspects of the present disclosure provides an overall length fixed type zoom lens that has a high zoom magnification and high optical performance over an overall zoom range. A zoom lens according to one aspect of the disclosure includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, a fourth lens unit having positive refractive power, and a fifth lens unit having negative refractive power. During zooming from a wide-angle end to a telephoto end, a distance between adjacent lens units changes, the first lens unit and the third lens unit are fixed, and the second lens unit and the fourth lens unit move. The third lens unit includes a negative lens and a positive lens. The following inequalities are satisfied: −3.50<β3w/β3t<−0.10 −10.0<f1/f2<−4.0 where β3w is a lateral magnification of the third lens unit at the wide-angle end, β3t is a lateral magnification of the third lens unit at the telephoto end, f1 is a focal length of the first lens unit, and f2 is a focal length of the second lens unit. An image pickup apparatus having the above zoom lens also constitutes another aspect of the disclosure. Further features of the disclosure will become apparent from the following description of embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a zoom lens according to Example 1. FIG. 2 is a sectional view of a zoom lens according to Example 2. FIG. 3 is a sectional view of a zoom lens according to Example 3. FIG. 4A is an aberration diagram of the zoom lens according to Example 1 at a wide-angle end and FIG. 4B is an aberration diagram of the zoom lens according to Example 1 at a telephoto end. FIG. 5A is an aberration diagram of the zoom lens according to Example 2 at a wide-angle end and FIG. 5B is an aberration diagram of the zoom lens according to Example 2 at a telephoto end. FIG. 6A is an aberration diagram of the zoom lens according to Example 3 at a wide-angle end and FIG. 6B is an aberration diagram of the zoom lens according to Example 3 at a telephoto end. FIG. 7 is a schematic diagram of an image pickup apparatus. DESCRIPTION OF THE EMBODIMENTS Referring now to the accompanying drawings, a description will be given of a zoom lens according to each example of the disclosure and an image pickup apparatus having the zoom lens. FIGS. 1, 2, and 3 are sectional views of the zoom lenses according to Examples 1 to 3, respectively, in in-focus states at infinity (or on the infinity object). The zoom lens according to each example is used for an image pickup apparatus such as a digital video camera, a digital still camera, a broadcasting camera, a film-based camera, a surveillance camera, and the like. In each lens sectional view, a left side is an object side and a right side is an image side. The zoom lens according to each example includes a plurality of lens units. In the specification of this application, a lens unit is a group o