Photographic optical system
The present invention discloses a photographic optical system which includes a first lens (focal length f1), a second lens (focal length f2), a third lens (focal length f3), a fourth lens (focal length f4), a fifth lens (focal length f5), a sixth lens (focal length f6) and a seventh lens (focal length f7). The photographic optical system disclosed in the present invention by optimizing rationally face shape, distributing focal power, selecting optical material, is designed as a big relative aperture photographic optical system, and can provide the imaging performance in low illumination environment.
1. A photographic optical system comprising, in an order from an object side to an image side:
a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens; wherein the photographic optical system further meets the following conditions (1)˜(7):
10< f 1/ f< 40 (1);
20< f 2/ f< 80 (2);
0.5< f 3/ f< 1.5 (3);
−2.5< f 4/ f<− 0.5 (4);
−10< f 5/ f<− 2 (5);
0.2< f 6/ f< 1.2 (6);
−1.5< f 7/ f<− 0.4 (7);
where,
f1: The focal length of the first lens;
f2: The focal length of the second lens;
f3: The focal length of the third lens;
f4: The focal length of the fourth lens;
f5: The focal length of the fifth lens;
f6: The focal length of the sixth lens;
f7: The focal length of the seven lens;
f: The focal length of whole photography optical system.
2. The photographic optical system as described in claim 1 further meeting the following conditions (1a)-(7a):
30 mm< f 1<150 mm (1a);
100 mm< f 2<500 mm (2a);
2 mm< f 3<5 mm (3a);
−10 mm< f 4<−2 mm (4a);
−30 mm< f 5<−10 mm (5a);
1mm< f 6<5 mm (6a);
−5 mm< f 7<−1.5 mm (7a).
3. The photographic optical system as described in claim 1 further meeting the following conditions (1b)-(7b):
1.50< n 1<1.55 (1b);
1.50< n 2<1.55 (2b);
1.50< n 3<1.55 (3b);
1.60< n 4<1.70 (4b);
1.60< n 5<1.70 (5b);
1.50< n 6<1.55 (6b);
1.50< n 7<1.55 (7b);
where,
n1: The refractive power of the first lens;
n2: The refractive power of the second lens;
n3: The refractive power of the third lens;
n4: The refractive power of the fourth lens;
n5: The refractive power of the fifth lens;
n6: The refractive power of the sixth lens;
n7: The refractive power of the seven lens.
4. The photography optical system as described in claim 1 further meeting the following conditions (1c)-(7c):
40< v 1<60 (1c);
40< v 2<60 (2c);
40< v 3<60 (3c);
15< v 4<30 (4c);
15< v 5<30 (5c);
40< v 6<60 (6c);
40< v 7<60 (7c);
where,
v1: Abbe number of the first lens;
v2: Abbe number of the second lens;
v3: Abbe number of the third lens;
v4: Abbe number of the fourth lens;
v5: Abbe number of the fifth lens;
v6: Abbe number of the sixth lens;
v7: Abbe number of the seven lens.
5. The photography optical system as described in claim 1 , wherein the first lens and the second lens meet following condition:
f 12>50 mm or f 12<−50 mm.
where,
f12: The combination focal length of the first lens and the second lens.
6. The photography optical system as described in claim 2 , wherein the first lens is a positive lens or a negative lens and the object side surface of the first lens is concave.
7. The photography optical system as described in claim 2 , wherein the seventh lens is a negative lens.
8. The photography optical system as described in claim 1 further meeting the following conditions:
TTL< 5.2 mm;
78°< FOV< 88°;
where,
TTL: The distance from the object side surface to the imaging surface of the first lens;
FOV: The biggest view angle range of the photographical optical system.
9. The photography optical system as described in claim 1 , wherein the ratio between the system optical overall length and focal length of the photographic optical system meets the following condition:
f/TTL> 0.65
where,
TTL: The distance from the object side surface to the imaging surface of the first lens.
10. The photography optical system as described in claim 7 , wherein the image side surface of the seventh lens has at least one point of inflection and one stagnation point.