Optical system and photographing device having optical system
An optical system includes: a first lens group having a positive refractive power, a second lens group having a negative refractive power and a third lens group having a positive or negative refractive power, arranged from an object side to an image side; when focusing, the second lens group moves along an optical axis, positions of the first and third lens groups relative to an imaging plane along the optical axis are fixed; when a lateral magnification of the third lens group at infinity is b3, a distance from a face closest to the object side of the entire optical system to the imaging plane is OAL, a focal length of the entire optical system focusing at infinity is f, and a maximum lateral magnification of the entire optical system is B, it is satisfied that: (0.80≤b3), (OAL/f≤2.00), (0.50≤|B|).
1 . An optical system, comprising:
a first lens group having a positive refractive power, a second lens group having a negative refractive power and a third lens group having a positive or negative refractive power, sequentially arranged from an object side to an image side;
when focusing, the second lens group moves along an optical axis, and positions of the first lens group and the third lens group relative to an imaging plane in a direction of the optical axis are fixed;
where a lateral magnification of the third lens group focusing at infinity is b3, a distance from a face closest to the object side of the entire optical system to the imaging plane is OAL, a focal length of the optical system focusing at infinity is f, and a maximum lateral magnification of the entire optical system is B, it is satisfied that:
0.8
≤
b
3
,
OAL
/
f
≤
2.
,
and
0.5
≤
❘
"\[LeftBracketingBar]"
B
❘
"\[RightBracketingBar]"
;
and
wherein the second lens group has:
at least one lens having a positive refractive power; and
at least one lens having a negative refractive power,
in the second lens group, a lens having the strongest positive refractive power is located closer to the image side than a lens having the strongest negative refractive power.
2 . An optical system, comprising:
a first lens group having a positive refractive power, a second lens group having a negative refractive power and a third lens group having a positive or negative refractive power, sequentially arranged from an object side to an image side,
when focusing, the second lens group moves along an optical axis, and positions of the first lens group and the third lens group relative to an imaging plane in a direction of the optical axis are fixed;
the second lens group has at least one lens having a positive refractive power,
when a refractive index of the lens having a positive refractive power based on a d-line is nd2p, an Abbe number of the lens having a positive refractive power based on the d-line is vd2p, and a variable is A, it is satisfied that:
nd
2
p
=
-
0.01
×
vd
2
p
+
A
1.55
≤
nd
2
p
≤
1.72
,
and
1.82
≤
A
≤
1.94
.
3 . The optical system according to claim 1 , wherein,
when a lateral magnification of the second lens group focusing at infinity is b2 and the lateral magnification of the third lens group focusing at infinity is b3, it is satisfied that:
-
10.
≤
(
1
-
b
2
2
)
×
b
3
2
≤
-
2.
.
4 . The optical system according to claim 1 , wherein,
when the focal length of the entire optical system focusing at infinity is f, and a focal length of the second lens group is f2, it is satisfied that:
-
0
.
7
0
≤
f
2
/
f
≤
-
0
.
1
0
.
5 . A photographing device, comprising:
an optical system according to claim 1 ; and
a photographing element arranged at a side of the imaging plane of the optical system and configured to convert an optical image formed by the optical system into an electrical signal.
6 . The optical system according to claim 1 , wherein,
it is satisfied that:
0.9
≤
b
3
≤
2.
.
7 . The optical system according to claim 6 , wherein it is satisfied that:
1.
≤
b
3
≤
1.2
.
8 . The optical system according to claim 1 , wherein it is satisfied that:
0.8
≤
OAL
/
f
≤
1.5
.
9 . The optical system according to claim 8 , wherein it is satisfied that:
0.9
≤
OAL
/
f
≤
1.
.
10 . The optical system according to claim 1 , wherein it is satisfied that:
0.75
≤
❘
"\[LeftBracketingBar]"
B
❘
"\[RightBracketingBar]"
.
11 . The optical system according to claim 10 , wherein it is satisfied that:
1.
≤
❘
"\[LeftBracketingBar]"
B
❘
"\[RightBracketingBar]"
.
12 . The optical system according to claim 2 , wherein,
the second lens group has:
at least one lens having a negative refractive power,
in the second lens group, a lens having the strongest positive refractive power is located closer to the image side than a lens having the strongest negative refractive power.
13 . The optical system according to claim 2 , wherein,
a lateral magnification of the second lens group focusing at infinity is b2, the lateral magnification of the third lens group focusing at infinity is b3, and it is satisfied that:
-
1
0
.
0
0
≤
(
1
-
b
2
2
)
×
b
3
2
≤
-
2
.
0
0
.
14 . The optical system according to claim 2 , wherein,
the focal length of the optical system focusing at infinity is f, a focal length of the second lens group is f2, and it is satisfied that:
-
0
.
7
0
≤
f2
/
f
≤
-
0
.
1
0
.
15 . The optical system according to claim 2 , wherein it is satisfied that:
1.57
≤
nd
2
p
≤
1.7
.
16 . The optical system according to claim 15 , wherein it is satisfied that:
1.59
≤
nd
2
p
≤
1.68
.
17 . The optical system according to claim 2 , wherein it is satisfied that:
1.84
≤
A
≤
1.92
.
18 . The optical system according to claim 17 , wherein it is satisfied that:
1.
8
6
≤
A
≤
1.9
.
19 . A photographing device, comprising:
an optical system according to claim 2 ; and
a photographing element arranged at a side of the imaging plane of the optical system and configured to convert an optical image formed by the optical system into an electrical signal.