Camera lens

1. A camera lens, comprising from an object side to an image side:

a first lens having a positive refractive index;

a second lens having a negative refractive index;

a third lens having a positive refractive index;

a fourth lens having a negative refractive index; and

a fifth lens having a negative refractive index;

wherein the first, second, third, fourth and fifth lenses satisfy following conditional expressions (1)-(5):

0.5< f 1/ f< 0.7   (1);

−2< f 2/ f<− 0.5   (2);

1.6< f 3/ f<− 2.0   (3);

−2.1< f 4/ f<− 1.45   (4);

−1.5< f 5/ f<− 1.2   (5);

wherein,

f: focal length of the integral camera lens;

f 1 : focal length of the first lens;

f 2 : focal length of the second lens;

f 3 : focal length of the third lens;

f 4 : focal length of the fourth lens;

f 5 : focal length of the fifth lens.

2. The camera lens as described in claim 1 , wherein, the camera lens further satisfies following conditional expressions (1a)-(5a):

1.5 mm<f1<3.0 mm   (1a);

−5 mm< f 2<−2 mm   (2a);

8 mm<f3<15 mm   (3a);

−12 mm< f 4<−2 mm   (4a);

−10 mm< f 5<−4 mm   (5a).

3. The camera lens as described in claim 1 , wherein, the camera lens further satisfies following conditional expressions (1b)-(5b):

1.50<n1<1.55   (1b);

1.60<n2<1.70   (2b);

1.60<n3<1.70   (3b);

1.50<n4<1.55   (4b);

1.50<n5<1.55   (5b);

wherein,

n 1 : refractive index of the first lens;

n 2 : refractive index of the second lens;

n 3 : refractive index of the third lens;

n 4 : refractive index of the fourth lens;

n 5 : refractive index of the fifth lens.

4. The camera lens as described in claim 1 , wherein, the camera lens further satisfies following conditional expressions (1c)-(5c):

40<v1<60   (1c);

15<v2<30   (2c);

15<v3<30   (3c);

40<v4<60   (4c);

40<v5<60   (5c);

wherein,

v 1 : Abbe number of the first lens;

v 2 : Abbe number of the second lens;

v 3 : Abbe number of the third lens;

v 4 : Abbe number of the fourth lens;

v 5 : Abbe number of the fifth lens.

5. The camera lens as described in claim 1 , wherein, the first lens is a positive focal power lens, which undertakes main focal power of the camera lens, so as to reduce optical length, the focal length thereof satisfies conditional expression: 1.5 mm<f 1 <3.0 mm.

6. The camera lens as described in claim 1 , wherein, the second lens and the third lens adopt a high refractive index and a material with a low Abbe number, so as to reasonably calibrate chromatic aberration of a system, the second lens satisfies conditional expressions: 1.60<n 2 <1.70 and 15<v 2 <30, the third lens satisfies conditional expressions: 1.60<n 3 <1.70 and 15<v 3 <30;

wherein,

n 2 : refractive index of the second lens;

n 3 : refractive index of the third lens;

v 2 : Abbe number of the second lens;

v 3 : Abbe number of the third lens.

7. The camera lens as described in claim 1 , wherein, the fourth lens and the fifth lens are negative lenses, so as to effectively reduce field curvature of a system, the fourth lens satisfies conditional expression: −12 mm<f 4 <−2 mm, the fifth lens satisfies conditional expression: −10 mm<f 5 <−4 mm.

8. The camera lens as described in claim 1 , wherein, a ratio of the focal length of the camera lens to a total optical length further satisfies following conditional expression:

f/TTL< 1.07;

wherein,

f: focal length of the integral camera lens:

TTL: distance from an object-side surface of the first lens to an imaging surface.

9. The camera lens as described in claim 1 , wherein, an F value FNo of the camera lens further satisfies following conditional expression: FNo≤2.6;

wherein, FNo is a ratio of a total focal length of the camera lens to an entrance pupil diameter.

10. The camera lens as described in claim 1 , wherein, the camera lens further comprises an aperture arranged on a side of an object-side surface of the first lens towards the object side.