Zoom lens having a high zoom ratio and high performance over an entire zoom range and image pickup apparatus including the same
Provided is a zoom lens, including, in order from an object side to an image side: a first lens unit having a positive refractive power that does not move for zooming; a second lens unit having a negative refractive power that moves during zooming; at least one lens unit that moves during zooming; and a rear lens unit including an aperture stop, in which a focal length of the zoom lens at a wide angle end, a focal length of the first lens unit, a focal length of the second lens unit, and a half angle of field of the zoom lens at the wide angle end are appropriately set.
1. A zoom lens comprising in order from an object side to an image side:
a first lens unit having a positive refractive power and configured not to move for zooming;
a second lens unit having a negative refractive power and configured to move for zooming;
at least one lens unit configured to move for zooming; and
a rear lens unit including an aperture stop,
wherein an interval of each pair of adjacent lens units of the first lens unit, the second lens unit, the at least one lens unit and the rear lens unit is changed for zooming, and
wherein the zoom lens satisfies expressions
−12.00< f 1/ f 2<−4.00;
−0.99< f 2/(2× fW ×tan(ω_ W ))<−0.30; and
−0.05< f 2/ L 2 W<− 0.05,
where fW represents a focal length of the zoom lens at a wide angle end, f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, ω_W represents a half angle of field of the zoom lens al the wide angle end, and L 2 W represents an interval on an optical axis between a surface, closest to the image side, of the second lens unit and a surface, closest to the object side, of the at least one lens unit at the wide angle end.
2. A zoom lens according to claim 1 , wherein the zoom lens satisfies an expression
9.00<β2 T/β 2 W< 35.00,
where β2W represents a lateral magnification of the second lens unit at the wide angle end and at infinity in an object distance, and β2T represents a lateral magnification of the second lens unit at a telephoto end and at infinity in the object distance.
3. A zoom lens according to claim 1 , wherein the zoom lens satisfies an expression
4.00< LF /(2× fW ×tan(ω_ W ))<20.00,
where LF represents a distance on an optical axis from a surface, closest to the object side, of the first lens unit to the aperture stop.
4. A zoom lens according to claim 1 , wherein the zoom lens satisfies an expression
10.00< fT /(2× fW ×tan(ω_ W ))<40.00,
where fT represents a focal length of the zoom lens at a telephoto end.
5. A zoom lens according to claim 1 , wherein the aperture stop does not move for zooming.
6. An image pickup apparatus, comprising:
a zoom lens comprising, in order from an object side to an image side:
a first lens unit having a positive refractive power and configured not to move for zooming;
a second lens unit having a negative refractive power and configured to move for zooming;
at least one lens unit configured to move for zooming; and
a rear lens unit including an aperture stop,
wherein an interval of each pair of adjacent lens units of the first lens unit, the second lens unit, the at least one lens unit and the rear lens unit is changed for zooming, and
wherein the zoom lens satisfies expressions
−12.00< f 1/ f 2<−4.00;
−0.99< f 2/(2 ×fW ×tan(ω_ W ))<−0.30; and
−0.50< f 2/ L 2 W<− 0.05,
where fW represents a focal length of the zoom lens at a wide angle end, f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, ω_W represents a half angle of field of the zoom lens at the wide angle end, and L 2 W represents an interval on an optical axis between a surface, closest to the image side, of the second lens unit and a surface, closest to the object side, of the at least one lens unit at the wide angle end; and
an image pickup element configured to receive an image formed by the zoom lens.
7. A zoom lens according to claim 1 , wherein the zoom lens performs focusing with a lens unit which is disposed on an object side of the aperture stop.
8. A zoom lens according to claim 1 , wherein the zoom lens satisfies an expression
2.00< fT/f 1<8.00,
where fT represents a focal length of the zoom lens at a telephoto end.
9. A zoom lens according to claim 1 , wherein the zoom lens satisfies an expression
2.39≤ fT/f 1<8.00,
where fT represents a focal length of the zoom lens at a telephoto end.
10. A zoom lens according to claim 1 , wherein the zoom lens satisfies an expression
3.59≤ fT/f 1<8.00,
where fT represents a focal length of the zoom lens at a telephoto end.
11. A zoom lens according to claim 1 , wherein the zoom lens satisfies an expression
−12.00< f 1/ f 2<−5.00.
12. A zoom lens comprising in order from an object side to an image side:
a first lens unit having a positive refractive power and configured not to move for zooming;
a second lens unit having a negative refractive power and configured to move for zooming;
at least one lens unit configured to move for zooming; and
a rear lens unit including an aperture stop,
wherein an interval of each pair of adjacent lens units of the first lens unit, the second lens unit, the at least one lens unit and the rear lens unit is changed for zooming, and
wherein the zoom lens satisfies expressions
−12.00< f 1/ f 2<−5.00;
−1.00< f 2/(2× fW ×tan(ω_ W ))<−0.30; and
−0.50< f 2/ L 2 W<− 0,05,
where fW represents a focal length of the zoom lens at a wide angle end, f1 represents a focal length of the first lens unit, f2 represents a focal length of the second lens unit, ω_W represents a half angle of field of the zoom lens at the wide angle end, and L 2 W represents an interval on art optical axis between a surface, closest to the image side, of the second lens unit and a surface, closest to the object side, of the at least one lens unit at the wide angle end.
13. A zoom lens according to claim 12 , wherein the zoom lens satisfies an expression
9.00<β2 T/β 2 W< 35.00,
where β2W represents a lateral magnification of the second lens unit at the wide angle end and at infinity in an object distance, and β2T represents a lateral magnification of the second lens unit at a telephoto end and at infinity in the object distance.
14. A zoom lens according to claim 12 , wherein the zoom lens satisfies an expression
4.00< LF /(2× fW ×tan(ω_ W ))<20.00,
where LF represents a distance on an optical axis from a surface, closest to the object side, of the first lens unit to the aperture stop.
15. A zoom lens according to claim 12 , wherein the zoom lens satisfies an expression
10.00< fT /(2× fW ×tan(ω_ W ))<40.00
where fT represents a focal length of the zoom lens at a telephoto end.
16. A zoom lens according to claim 12 , wherein the aperture stop does not move for zooming.
17. An image pickup apparatus comprising:
a zoom lens defined in claim 12 ; and
an image pickup element configured to receive an image formed by the zoom lens.
18. A zoom lens according to claim 12 , wherein the zoom lens performs focusing with a lens unit which is disposed on art object side of the aperture stop.
19. A zoom lens according to claim 12 , wherein the zoom lens satisfies an expression
2.00< fT/f 1<8.00,
where fT represents a focal length of the zoom lens at a telephoto end.