Photographic optical system

1. A photographic optical system comprising, in an order from an object side to an image side:

a first lens with double convex surfaces and having positive refractive power;

a second lens with a convex object side surface and a concave image side surface;

a third lens with a concave object side surface and a convex image side surface;

a fourth lens with double convex surfaces;

a fifth lens with a concave object side surface and a convex image side surface;

a sixth lens having negative refractive power, and having a concave object side surface and a convex image side surface;

a seventh lens with negative refractive power, including a concave object side surface and an image side surface transferred from concave to convex from area near optical axis to circumference; wherein the photographic optical system meets the following conditions (1)˜(7):

0.6< fl/f< 0.95  (1)

−2< f 2/ f<− 1.5  (2)

−3.5< f 3/ f<− 1.2  (3)

1.5< f 4/ f< 2.5  (4)

0.5< f 5/ f< 1.0  (5)

−10< f 6/ f<− 5  (6)

−1< f 7/ f<− 0.5  (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 satisfying the following conditions:

1.5 mm< f 1<3 mm  (1a)

−6 mm< f 2<−4 mm  (2a)

−15 mm< f 3<7 mm  (3a)

5 mm< f 4<10 mm  (4a)

5 mm< f 5<10 mm  (5a)

−35 mm< f 6<−30 mm  (6a)

−5 mm< f 7<−2 mm  (7a).

3. The photographic optical system as described in claim 1 further satisfying the following conditions:

1.50< n 1<1.55  (1b)

1.60< n 2<1.70  (2b)

1.60< n 3<1.70  (3b)

1.50< n 4<1.55  (4b)

1.50< n 5<1.55  (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 satisfying the following conditions:

40< v 1<60  (1c)

15< v 2<30  (2c)

15< v 3<30  (3c)

40< v 4<60  (4c)

40< v 5<60  (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 photographic optical system as described in claim 1 , wherein the first lens undertakes main optical refractive power of the photographic optical system.

6. The photographic optical system as described in claim 1 , wherein a ratio between the focal length and the system total optical length of the photographic optical system meets following condition expression:

f/TTL> 0.7

wherein TTL is the distance from the object side surface to the imaging surface of the first lens.

7. The photographic optical system as described in claim 1 , wherein the second lens and the third lens are made of material with high refractive index and low abbe number.

8. The photographic optical system as described in claim 1 , wherein the sixth lens and seventh lens are negative lenses.

9. The photographic optical system as described in claim 1 further satisfying the following condition expression:

TTL< 4.9 mm;

78°<FOV<88°;

where, FOV is the biggest view angle range of the photographical optical system.

10. The photographic optical system as described in claim 6 , wherein the image side surface of the seventh lens has at least one point of inflection and one stagnation point.