US 12,292,556 B2
Zoom lens and image pickup apparatus
Shunji Iwamoto, Tochigi (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Oct. 31, 2023, as Appl. No. 18/498,090.
Application 18/498,090 is a continuation of application No. 17/331,696, filed on May 27, 2021, granted, now 11,841,489.
Claims priority of application No. 2020-099674 (JP), filed on Jun. 8, 2020.
Prior Publication US 2024/0061224 A1, Feb. 22, 2024
Int. Cl. G02B 15/16 (2006.01); G02B 15/14 (2006.01)
CPC G02B 15/1461 (2019.08) [G02B 15/16 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A zoom lens comprising, in order from an object side to an image side:
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power; and
a rear group having a plurality of lens units,
wherein the rear group includes a lens unit LR closest to an image plane,
wherein each distance between adjacent lens units changes during zooming,
wherein a lens disposed closest to the image side in the zoom lens is a biconvex lens, and
wherein the following inequalities are satisfied:
−4.0<mr/bfw<−1.5
−7.0<m3/bfw<−2.5
where mr is a difference between a position of the lens unit LR relative to the image plane at the telephoto end and a position of the lens unit LR relative to the image plane at a wide-angle end, a sign of mr being negative when the lens unit LR is positioned closer to the object side at the telephoto end than at the wide-angle end, bfw is a distance on an optical axis from a surface closest to the image plane of the lens unit LR to the image plane at the wide-angle end, m3 is a difference between a position of the third lens unit relative to the image plane at the telephoto end and a position of the third lens unit relative to the image plane at the wide-angle end, a sign of m3 being negative when the third lens unit is positioned closer to the object side at the telephoto end than at the wide-angle end.