Back to results
US 2022/0035143 A1Published application
Zoom lens and imaging apparatus
AssigneeFUJIFILM Corporation
InventorDaiki KAWAMURA
Life of this patent
Estimating the term…
Abstract
A zoom lens includes a negative first lens group, a positive second lens group, and a subsequent lens group in order from an object side. A focusing lens group closer to an image side than the first lens group moves during focusing. The first lens group consists of a first-a lens group and a first-b lens group in order from the object side. Assuming that an average of refractive indices of the negative lenses of the first-a lens group is Nd1ave, a focal length of the focusing lens group is ff, and a focal length of the first lens group is f1, Conditional Expression (1) of 1.73<Nd1ave<1.95 and Conditional Expression (2) of 1<|ff/f1|<3 are satisfied.
Claims30
A zoom lens consisting of:
- in order from an object side to an image side,
- a first lens group having a negative refractive power;
- a second lens group having a positive refractive power;
- and
- a subsequent lens group,
- wherein mutual distances between the first lens group, the second lens group, and the subsequent lens group change due to movement of at least the first lens group and the second lens group during zooming,
- a focusing lens group disposed so as to be closer to the image side than the first lens group moves during focusing from an object at infinity from an object within a short range,
- the first lens group includes a negative lens, a negative lens of which a convex surface faces the object side, and a negative lens, consecutively, in order from a side closest to the object side to the image side,
- the first lens group includes a positive lens closest to the image side,
- a biconcave lens is disposed so as to be adjacent to an object side of the positive lens closest to an image side in the first lens group,
- a total number of cemented lenses, disposed so as to be closer to the image side than the first lens group, consisting of, in order from the object side, one negative lens of which an object-side surface is in contact with air and one positive lens of which an image-side surface is in contact with air, is four, and
- assuming that an on-axis air-equivalent distance from a lens surface closest to the image side to an image plane in a state in which the object at infinity at the wide-angle end is in focus is BFw, a focal length of the zoom lens in a state in which the object at infinity at the wide-angle end is in focus is fw, a maximum half-angle of view in a state in which the object at infinity at the wide-angle end is in focus is ωw, and an open F number at the wide-angle end is FNow, Conditional Expressions (8-4) and (9) are satisfied,
- 0.714≤BFw/(fw×tan ωw)<1.5 (8-4), and
- 0.45<tan ωw/FNow<1 (9).
11 more elements
An imaging apparatus comprising a zoom lens,
- wherein the zoom lens consists of:
- in order from an object side to an image side,
- a first lens group having a negative refractive power;
- a second lens group having a positive refractive power;
- and
- a subsequent lens group,
- wherein mutual distances between the first lens group, the second lens group, and the subsequent lens group change due to movement of at least the first lens group and the second lens group during zooming,
- a focusing lens group disposed so as to be closer to the image side than the first lens group moves during focusing from an object at infinity from an object within a short range,
- the first lens group includes a negative lens, a negative lens of which a convex surface faces the object side, and a negative lens, consecutively, in order from a side closest to the object side to the image side,
- the first lens group includes a positive lens closest to the image side,
- a biconcave lens is disposed so as to be adjacent to an object side of the positive lens closest to an image side in the first lens group,
- a total number of cemented lenses, disposed so as to be closer to the image side than the first lens group, consisting of, in order from the object side, one negative lens of which an object-side surface is in contact with air and one positive lens of which an image-side surface is in contact with air, is four, and
- assuming that an on-axis air-equivalent distance from a lens surface closest to the image side to an image plane in a state in which the object at infinity at the wide-angle end is in focus is BFw, a focal length of the zoom lens in a state in which the object at infinity at the wide-angle end is in focus is fw, a maximum half-angle of view in a state in which the object at infinity at the wide-angle end is in focus is ωw, and an open F number at the wide-angle end is FNow, Conditional Expressions (8-4) and (9) are satisfied,
- 0.714≤BFw/(fw×tan ωw)<1.5 (8-4), and
- 0.45<tan ωw/FNow<1 (9).
12 more elements
Dependencies are inferred from the claim text.