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US-12625353-B2 - Zoom lens and apparatus including the same

US12625353B2US 12625353 B2US12625353 B2US 12625353B2US-12625353-B2

Abstract

A zoom lens includes a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a rear lens group including one or more lens units, which are disposed in this order from an object side to an image side, wherein a distance between adjacent lens units changes in zooming, wherein the first lens unit does not move and the second lens unit moves in zooming, wherein the second lens unit includes subunits L 2 a and L 2 b having a positive refractive power, which are disposed in this order from the object side, wherein the subunit L 2 a moves to include a component in a direction perpendicular to an optical axis in image stabilization, wherein the rear lens group includes a focus lens unit that moves in focusing, and wherein the zoom lens satisfies predetermined inequalities.

Inventors

  • Yuki Shinzato
  • Shunji Iwamoto

Assignees

  • CANON KABUSHIKI KAISHA

Dates

Publication Date
20260512
Application Date
20231120
Priority Date
20221125

Claims (20)

  1. 1 . A zoom lens comprising a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a rear lens group including one or more lens units, which are disposed in this order from an object side to an image side, a distance between adjacent lens units changing in zooming, wherein the first lens unit is configured to not move and the second lens unit is configured to move in zooming, wherein the second lens unit includes subunits L 2 a and L 2 b having a positive refractive power, which are disposed in this order from the object side, wherein the subunit L 2 a is configured to move so as to include a component in a direction perpendicular to an optical axis in image stabilization, wherein the rear lens group includes a focus lens unit configured to move in focusing, and wherein the following inequalities are satisfied: 0.21<( R 1+ R 2)/( R 1− R 2)<5.00; 0.1<| f 1|/ f 2<3.0 where R1 denotes a curvature radius of a lens surface disposed closest to the object side in the subunit L 2 a , R2 denotes a curvature radius of a lens surface disposed closest to the image side in the subunit L 2 a , f1 denotes a focal length of the first lens unit, and f2 denotes a focal length of the second lens unit.
  2. 2 . The zoom lens according to claim 1 , wherein the subunit L 2 a includes one lens element.
  3. 3 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: 2.2< f 2 a/f 2<6.0 where f2a denotes a focal length of the subunit L 2 a.
  4. 4 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: 1.2< f 2 a/ft< 4.5 where f2a denotes a focal length of the subunit L 2 a , and ft denotes a focal length of an entire system at a telephoto end.
  5. 5 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: 1.6< f 2 a/f 2 b< 5.0 where f2a denotes a focal length of the subunit L 2 a , and f2b denotes a focal length of the subunit L 2 b.
  6. 6 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: 0.4<(1−β t 2 a )* Btr< 1.5 where βt2a denotes a lateral magnification of the subunit L 2 a at a telephoto end, and βtr denotes a combined lateral magnification of all lenses disposed on the image side of the subunit L 2 a at the telephoto end.
  7. 7 . The zoom lens according to claim 1 , wherein the focus lens unit is a lens unit disposed closest to the object side in the rear lens group.
  8. 8 . The zoom lens according to claim 1 , wherein the subunit L 2 b includes an aperture diaphragm, and wherein the following inequality is satisfied: 0.035< X 2 asp/TTL< 0.2 where X2asp denotes a distance on the optical axis from the lens surface disposed closest to the object side in the subunit L 2 a to the aperture diaphragm, and TTL denotes a total optical length of the zoom lens.
  9. 9 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: 0.25< X 2 a 3/ TTL< 0.46 where X2a3 denotes a distance on the optical axis from the lens surface disposed closest to the object side in the subunit L 2 a to a lens surface disposed closest to the image side in the focus lens unit at a wide-angle end, and TTL denotes a total optical length of the zoom lens.
  10. 10 . The zoom lens according to claim 1 , wherein the subunit L 2 b includes an aperture diaphragm, and wherein the following inequality is satisfied: 0.09< X 2 asp /( X 2 asp+X 2 a 3)<0.4 where X2asp denotes a distance on the optical axis from the lens surface disposed closest to the object side in the subunit L 2 a to the aperture diaphragm, and X2a3 denotes a distance on the optical axis from the lens surface disposed closest to the object side in the subunit L 2 a to a lens surface disposed closest to the image side in the focus lens unit at a wide-angle end.
  11. 11 . The zoom lens according to claim 1 , wherein the second lens unit and the focus lens unit are configured to move to the object side in zooming from a wide-angle end to a telephoto end.
  12. 12 . The zoom lens according to claim 1 , wherein the focus lens unit has a negative refractive power, and is configured to move to the image side in focusing from infinity to a close distance.
  13. 13 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: 0.1<| f 1|/ fw< 3.5 where fw denotes a focal length of an entire system at a wide-angle end.
  14. 14 . The zoom lens according to claim 1 , wherein a third lens unit as the focus lens unit is disposed closest to the object side in the rear lens group, and wherein the following inequality is satisfied: 1.2<| f 3|/ fw< 5.6 where f3 denotes a focal length of the third lens unit, and fw denotes a focal length of an entire system at a wide-angle end.
  15. 15 . The zoom lens according to claim 1 , wherein the first lens unit includes two or more lenses.
  16. 16 . The zoom lens according to claim 15 , wherein the first lens unit includes a positive lens and a negative lens.
  17. 17 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: 0.05< TL 1/ TTL< 0.2 where TL1 denotes a total lens length of the first lens unit, and TTL denotes a total optical length of the zoom lens.
  18. 18 . The zoom lens according to claim 1 , wherein the following inequality is satisfied: 0.4< BFw/f 2<1.2 where BFw denotes a back focus of the zoom lens at a wide-angle end.
  19. 19 . The zoom lens according to claim 1 , wherein a last lens unit having a positive refractive power is disposed closest to the image side in the rear lens group, and the last lens unit is configured to not move in zooming.
  20. 20 . The zoom lens according to claim 1 , wherein a last lens unit having a positive refractive power is disposed closest to the image side in the rear lens group, and the last lens unit includes one lens element.

Description

BACKGROUND Technical Field The aspect of the embodiments relates to zoom lenses, and is suitable for apparatuses such as digital video cameras, digital still cameras, broadcasting cameras, and silver-halide film cameras. Description of the Related Art In recent years, wide-angle zoom lenses having an image stabilizing function have been widely used for moving image capturing. As such wide-angle zoom lenses, optical systems having high optical performance and achieving both a compact size and a wide angle of view have been demanded. Japanese Patent Application Laid-Open No. 2007-279147 discusses a negative-lead type zoom lens including a second lens unit as an image stabilization unit. Generally with the increase in the number of lenses moving for image stabilization, an actuator for driving these lenses is likely to increase in size. To achieve the downsizing of the zoom lens, the image stabilization unit that moves for image stabilization is formed of as small a number of lenses as possible. In the zoom lens discussed in Japanese Patent Application Laid-Open No. 2007-279147, the entire second lens unit serves as an image stabilization unit; thus it is difficult to achieve sufficient downsizing of the zoom lens. SUMMARY According to an aspect of the embodiments, a zoom lens includes a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a rear lens group including one or more lens units, which are disposed in this order from an object side to an image side, wherein a distance between adjacent lens units changes in zooming, wherein the first lens unit is configured to not move and the second lens unit is configured to move in zooming, wherein the second lens unit includes subunits L2a and L2b having a positive refractive power, which are disposed in this order from the object side, wherein the subunit L2a is configured to move so as to include a component in a direction perpendicular to an optical axis in image stabilization, wherein the rear lens group includes a focus lens unit configured to move in focusing, and wherein the following inequalities are satisfied: 0.21<(R1+R2)/(R1−R2)<5.00 0.1<|f1|/f2<3.0 where R1 denotes a curvature radius of a lens surface disposed closest to the object side in the subunit L2a, R2 denotes a curvature radius of a lens surface disposed closest to the image side in the subunit L2a, f1 denotes a focal length of the first lens unit, and f2 denotes a focal length of the second lens unit. 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 cross-sectional view illustrating a zoom lens at a wide-angle end according to a first embodiment. FIGS. 2A, 2B, and 2C are aberration diagrams of the zoom lens at the wide-angle end, an intermediate zoom position, and a telephoto end, respectively, according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a zoom lens at a wide-angle end according to a second embodiment. FIGS. 4A, 4B, and 4C are aberration diagrams of the zoom lens at the wide-angle end, an intermediate zoom position, and a telephoto end, respectively, according to the second embodiment. FIG. 5 is a cross-sectional view illustrating a zoom lens at a wide-angle end according to a third embodiment. FIGS. 6A, 6B, and 6C are aberration diagrams of the zoom lens at the wide-angle end, an intermediate zoom position, and a telephoto end, respectively, according to the third embodiment. FIG. 7 is a cross-sectional view illustrating a zoom lens at a wide-angle end according to a fourth embodiment. FIGS. 8A, 8B, and 8C are aberration diagrams of the zoom lens at the wide-angle end, an intermediate zoom position, and a telephoto end, respectively, according to the fourth embodiment. FIG. 9 is a cross-sectional view illustrating a zoom lens at a wide-angle end according to a fifth embodiment. FIGS. 10A, 10B, and 10C are aberration diagrams of the zoom lens at the wide-angle end, an intermediate zoom position, and a telephoto end, respectively, according to the fifth embodiment. FIG. 11 is a cross-sectional view illustrating a zoom lens at a wide-angle end according to a sixth embodiment. FIGS. 12A, 12B, and 12C are aberration diagrams of the zoom lens at the wide-angle end, an intermediate zoom position, and a telephoto end, respectively, according to the sixth embodiment. FIG. 13 is a cross-sectional view illustrating a zoom lens at a wide-angle end according to a seventh embodiment. FIGS. 14A, 14B, and 14C are aberration diagrams of the zoom lens at the wide-angle end, an intermediate zoom position, and a telephoto end, respectively, according to the seventh embodiment. FIG. 15 is a cross-sectional view illustrating a zoom lens at a wide-angle end according to an eighth embodiment. FIGS. 16A, 16B, and 16C are aberration diagrams of the zoom lens at the wide-angle end, an