Photographing lens assembly including eight lenses of +−++−−+−, +−−++−+−, +−−+−−+−, +−−−+−+− or +−−+−++−refractive powers

1. A photographing lens assembly comprising eight lens elements, the eight lens elements being, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element, and a total number of lens elements of the photographing lens assembly is eight;

wherein the sixth lens element has negative refractive power, the seventh lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof and has an image-side surface being concave in a paraxial region thereof, and the eighth lens element has an object-side surface being concave in a paraxial region thereof;

wherein a central thickness of the first lens element is CT1, a maximum value among central thicknesses of the second through eighth lens elements is MaxCT28, an axial distance between an object-side surface of the third lens element and an image-side surface of the fifth lens element is Dr5r10, an axial distance between an object-side surface of the sixth lens element and an image-side surface of the eighth lens element is Dr11r16, and the following conditions are satisfied:

1.0< CT 1/Max CT 28, and

Dr 5 r 10/ Dr 11 r 16<0.90.

2. The photographing lens assembly of claim 1 , wherein an axial distance between the first lens element and the second lens element is T12, an axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, an axial distance between the fourth lens element and the fifth lens element is T45, an axial distance between the fifth lens element and the sixth lens element is T56, an axial distance between the sixth lens element and the seventh lens element is T67, an axial distance between the seventh lens element and the eighth lens element is T78, and the following conditions are satisfied:

1.0< T 78/ T 12;

1.0< T 78/ T 23;

1.0< T 78/ T 34;

1.0< T 78/ T 45,

1.0< T 78/ T 56; and

1.10< T 78/ T 67.

3. The photographing lens assembly of claim 1 , wherein an axial distance between the seventh lens element and the eighth lens element is T78, an axial distance between the image-side surface of the eighth lens element and an image surface is BL, and the following condition is satisfied:

0.80< T 78/ BL.

4. The photographing lens assembly of claim 1 , wherein an f-number of the photographing lens assembly is Fno, half of a maximum field of view of the photographing lens assembly is HFOV, and the following condition is satisfied:

Fno /tan (HFOV)<2.20.

5. The photographing lens assembly of claim 1 , wherein an Abbe number of the first lens element is V1, an Abbe number of the second lens element is V2, an Abbe number of the third lens element is V3, an Abbe number of the fourth lens element is V4, an Abbe number of the fifth lens element is V5, an Abbe number of the sixth lens element is V6, an Abbe number of the seventh lens element is V7, an Abbe number of the eighth lens element is V8, an Abbe number of the i-th lens element is Vi, a refractive index of the first lens element is N1, a refractive index of the second lens element is N2, a refractive index of the third lens element is N3, a refractive index of the fourth lens element is N4, a refractive index of the fifth lens element is N5, a refractive index of the sixth lens element is N6, a refractive index of the seventh lens element is N7, a refractive index of the eighth lens element is N8, a refractive index of the i-th lens element is Ni, and at least two lens elements of the photographing lens assembly satisfy the following condition:

5.0< Vi/Ni< 12.0, wherein i= 1,2,3,4,5,6,7 or 8.

6. The photographing lens assembly of claim 1 , wherein an axial distance between an object-side surface of the first lens element and an image surface is TL, a maximum image height of the photographing lens assembly is ImgH, an axial distance between the image-side surface of the eighth lens element and the image surface is BL, and the following conditions are satisfied:

TL/ImgH< 1.60; and

5.0 <ImgH/BL.

7. The photographing lens assembly of claim 1 , wherein the axial distance between the object-side surface of the third lens element and the image-side surface of the fifth lens element is Dr5r10, the axial distance between the object-side surface of the sixth lens element and the image-side surface of the eighth lens element is Dr11r16, and the following condition is satisfied:

0.30< Dr 5 r 10/ Dr 11 r 16<0.75.

8. The photographing lens assembly of claim 1 , wherein an axial distance between the seventh lens element and the eighth lens element is T78, a central thickness of the seventh lens element is CT7, a central thickness of the eighth lens element is CT8, and the following condition is satisfied:

< T 78/( CT 7+ CT 8)<1.5.

9. The photographing lens assembly of claim 1 , wherein a focal length of the photographing lens assembly is f, a composite focal length of the first lens element and the second lens element is f12, a composite focal length of the third lens element, the fourth lens element and the fifth lens element is f345, a composite focal length of the sixth lens element, the seventh lens element and the eighth lens element is f678, and the following conditions are satisfied:

0 <f 12 /f 345 <1.50; and

f/f 678<−0.20.

10. The photographing lens assembly of claim 1 , wherein a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the third lens element is f3, a focal length of the fourth lens element is f4, a focal length of the fifth lens element is f5, a focal length of the sixth lens element is f6, a focal length of the seventh lens element is f7, a focal length of the eighth lens element is f8, and the following conditions are satisfied:

| f 8/ f 1|<1.0;

| f 8/ f 2|<1.0;

| f 8/ f 3|<1.0;

| f 8/ f 4|<1.0;

| f 8/ f 5|<1.0;

| f 8/ f 6|<1.0; and

| f 8/ f 7|<1.0.

11. The photographing lens assembly of claim 1 , wherein a focal length of the seventh lens element is f7, a focal length of the eighth lens element is f8, and the following condition is satisfied:

f 7/ f 8<−0.50.

12. The photographing lens assembly of claim 1 , wherein the first lens element has positive refractive power, and the eighth lens element has negative refractive power.