Patent ID: 11966030
Assignee: FUJIFILM CORPORATION
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A zoom lens consisting of, in order from an object side to an image side, a first lens group that has a negative refractive power, a middle group, and a final group,
wherein during zooming, a spacing between the first lens group and the middle group changes, and a spacing between the middle group and the final group changes,
during focusing, at least a part of the middle group moves along an optical axis as a focus group, and the first lens group and the final group remain stationary with respect to an image plane,
a back focal length of the zoom lens at an air conversion distance at a wide angle end in a state where an infinite distance object is in focus is Bfw,
a focal length of the zoom lens at the wide angle end in the state where the infinite distance object is in focus is fw,
a maximum half angle of view at the wide angle end in the state where the infinite distance object is in focus is ωw,
Conditional Expression (1) is satisfied, which is represented by

0.35<Bfw/(fw×tan|ωw|)<1.5  (1),

an amount of movement of the focus group in a case of changing from the state in which the infinite distance object is in focus to a state in which an imaging magnification is −0.1 times, at a telephoto end, is Dfoct,
a difference in a direction of the optical axis between a position of a lens surface closest to the object side in the middle group at the telephoto end and a position of the lens surface closest to the object side in the middle group at the wide angle end, in the state in which the infinite distance object is in focus, is DpM, and
Conditional Expression (2) is satisfied, which is represented by

0.005<|Dfoct/DpM|<0.3  (2).