Patent Publication Number: US-11644651-B2

Title: Image capturing lens system, image capturing unit and electronic device including eight lenses of +−+−++−+, +−+−+−+ or +−−+−−+− refractive powers

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application 63/059,800, filed on Jul. 31, 2020, which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to an image capturing lens system, an image capturing unit and an electronic device, more particularly to an image capturing lens system and an image capturing unit applicable to an electronic device. 
     Description of Related Art 
     With the development of semiconductor manufacturing technology, the performance of image sensors has improved, and the pixel size thereof has been scaled down. Therefore, featuring high image quality becomes one of the indispensable features of an optical system nowadays. 
     Furthermore, due to the rapid changes in technology, electronic devices equipped with optical systems are trending towards multi-functionality for various applications, and therefore the functionality requirements for the optical systems have been increasing. However, it is difficult for a conventional optical system to obtain a balance among the requirements such as high image quality, low sensitivity, a proper aperture size, miniaturization and a desirable field of view. 
     SUMMARY 
     According to one aspect of the present disclosure, an image capturing lens system includes four lens groups, and the four lens groups include eight lens elements. The four lens groups are, in order from an object side to an image side along an optical path, a first lens group, a second lens group, a third lens group and a fourth lens group. The eight lens elements are, in order from the object side to the image side along the optical path, 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. Each of the eight lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. 
     The first lens group includes the first lens element and the second lens element, the second lens group includes the third lens element, the fourth lens element and the fifth lens element, the third lens group includes the sixth lens element and the seventh lens element, and the fourth lens group includes the eighth lens element. The first lens element has positive refractive power. The second lens element has negative refractive power. At least one lens element in the second lens group, the third lens group and the fourth lens group has at least one inflection point in an off-axis region thereof. 
     A focal length of the image capturing lens system is varied by changing axial distances between the four lens groups in a zooming process. The second lens group is moved relative to the first lens group along an optical axis in the zooming process, and the third lens group is moved relative to the first lens group along the optical axis in the zooming process. The image capturing lens system has a long-focal-length end and a short-focal-length end. 
     When an Abbe number of one of the eight lens elements is Vi, a refractive index of the one of the eight lens elements is Ni, a minimum value of Vi/Ni is (Vi/Ni) min, half of a maximum field of view of the image capturing lens system at the short-focal-length end is HFOVS, a maximum distance between an optically effective area of the object-side surface of the first lens element and the optical axis when the image capturing lens system is at the long-focal-length end is Y11L, a maximum distance between an optically effective area of the image-side surface of the eighth lens element and the optical axis when the image capturing lens system is at the long-focal-length end is Y82L, a maximum distance between an optically effective area of the object-side surface of the first lens element and the optical axis when the image capturing lens system is at the short-focal-length end is Y11S, a maximum distance between an optically effective area of the image-side surface of the eighth lens element and the optical axis when the image capturing lens system is at the short-focal-length end is Y82S, an axial distance between the object-side surface of the first lens element and the image-side surface of the eighth lens element when the image capturing lens system is at the long-focal-length end is TDL, and an axial distance between the object-side surface of the first lens element and the image-side surface of the eighth lens element when the image capturing lens system is at the short-focal-length end is TDS, the following conditions are satisfied:
 
7.5&lt;( Vi/Ni )min&lt;12.3;
 
3.0 degrees&lt; HFOVS &lt;25.0 degrees;
 
0.50 &lt;Y 11 L/Y 82 L &lt;2.0;
 
0.50 &lt;Y 11 S/Y 82 S &lt;2.0; and
 
| TDL/TDS− 1|&lt;1.0 E− 2.
 
     According to another aspect of the present disclosure, an image capturing lens system includes four lens groups, and the four lens groups include eight lens elements. The four lens groups are, in order from an object side to an image side along an optical path, a first lens group, a second lens group, a third lens group and a fourth lens group. The eight lens elements are, in order from the object side to the image side along the optical path, 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. Each of the eight lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. 
     The second lens group includes at least three lens elements. The first lens element has positive refractive power. The second lens element has negative refractive power. The third lens element has positive refractive power. At least one lens element in the second lens group, the third lens group and the fourth lens group has at least one inflection point in an off-axis region thereof. 
     A focal length of the image capturing lens system is varied by changing axial distances between the four lens groups in a zooming process. The second lens group is moved relative to the first lens group along an optical axis in the zooming process. The image capturing lens system has a long-focal-length end and a short-focal-length end. 
     When an Abbe number of one of the eight lens elements is Vi, a refractive index of the one of the eight lens elements is Ni, a minimum value of Vi/Ni is (Vi/Ni) min, half of a maximum field of view of the image capturing lens system at the short-focal-length end is HFOVS, a maximum distance between an optically effective area of the object-side surface of the first lens element and the optical axis when the image capturing lens system is at the long-focal-length end is Y11L, a maximum distance between an optically effective area of the image-side surface of the eighth lens element and the optical axis when the image capturing lens system is at the long-focal-length end is Y82L, a maximum distance between an optically effective area of the object-side surface of the first lens element and the optical axis when the image capturing lens system is at the short-focal-length end is Y11S, and a maximum distance between an optically effective area of the image-side surface of the eighth lens element and the optical axis when the image capturing lens system is at the short-focal-length end is Y82S, the following conditions are satisfied:
 
7.5&lt;( Vi/Ni )min&lt;12.3;
 
3.0 degrees&lt; HFOVS &lt;25.0 degrees;
 
0.50&lt; Y 11 L/Y 82 L&lt; 2.0; and
 
0.50&lt; Y 11 S/Y 82 S&lt; 2.0.
 
     According to another aspect of the present disclosure, an image capturing lens system includes four lens groups, and the four lens groups include eight lens elements. The four lens groups are, in order from an object side to an image side along an optical path, a first lens group, a second lens group, a third lens group and a fourth lens group. The eight lens elements are, in order from the object side to the image side along the optical path, 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. Each of the eight lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. 
     The first lens element has positive refractive power. The second lens element has negative refractive power. The third lens element has positive refractive power. The eighth lens element has positive refractive power. At least one lens element in the first lens group, the second lens group, the third lens group and the fourth lens group is made of plastic material. At least one lens element in the second lens group, the third lens group and the fourth lens group has at least one inflection point in an off-axis region thereof. 
     A focal length of the image capturing lens system is varied by changing axial distances between the four lens groups in a zooming process. The second lens group is moved relative to the first lens group along an optical axis in the zooming process. The image capturing lens system has a long-focal-length end and a short-focal-length end. 
     When an Abbe number of one of the eight lens elements is Vi, a refractive index of the one of the eight lens elements is Ni, a minimum value of Vi/Ni is (Vi/Ni) min, half of a maximum field of view of the image capturing lens system at the short-focal-length end is HFOVS, a maximum distance between an optically effective area of the object-side surface of the first lens element and the optical axis when the image capturing lens system is at the long-focal-length end is Y11L, a maximum distance between an optically effective area of the image-side surface of the eighth lens element and the optical axis when the image capturing lens system is at the long-focal-length end is Y82L, a maximum distance between an optically effective area of the object-side surface of the first lens element and the optical axis when the image capturing lens system is at the short-focal-length end is Y11S, and a maximum distance between an optically effective area of the image-side surface of the eighth lens element and the optical axis when the image capturing lens system is at the short-focal-length end is Y82S, the following conditions are satisfied:
 
7.5&lt;( Vi/Ni )min&lt;12.3;
 
3.0 degrees&lt; HFOVS &lt;25.0 degrees;
 
0.50&lt; Y 11 L/Y 82 L&lt; 2.0; and
 
0.50&lt; Y 11 S/Y 82 S&lt; 2.0.
 
     According to another aspect of the present disclosure, an image capturing unit includes one of the aforementioned image capturing lens systems and an image sensor, wherein the image sensor is disposed on an image surface of the image capturing lens system. 
     According to another aspect of the present disclosure, an electronic device includes at least two image capturing units located on the same side of the electronic device. The at least two image capturing units includes a first image capturing unit and a second image capturing unit. The first image capturing unit includes one of the aforementioned image capturing lens systems and an image sensor disposed on an image surface of the image capturing lens system. The second image capturing unit includes an optical lens assembly and an image sensor disposed on an image surface of the optical lens assembly. In addition, half of a maximum field of view of the second image capturing unit ranges from 30 degrees to 60 degrees. 
     According to another aspect of the present disclosure, an electronic device includes at least two image capturing units located on the same side of the electronic device. The at least two image capturing units includes a first image capturing unit and a second image capturing unit. The first image capturing unit includes one of the aforementioned image capturing lens systems and an image sensor disposed on an image surface of the image capturing lens system. The second image capturing unit includes an optical lens assembly and an image sensor disposed on an image surface of the optical lens assembly. In addition, half of a maximum field of view of the second image capturing unit ranges from 30 degrees to 60 degrees, and a movement direction of lens groups of the first image capturing unit is perpendicular to an optical axis of at least another of the at least two image capturing units. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure can be better understood by reading the following detailed description of the embodiments, with reference made to the accompanying drawings as follows: 
         FIG.  1    is a schematic view of an image capturing unit at the short-focal-length end according to the 1st embodiment of the present disclosure; 
         FIG.  2    is a schematic view of the image capturing unit at the long-focal-length end according to the 1st embodiment of the present disclosure; 
         FIG.  3    shows spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at the short-focal-length end according to the 1st embodiment; 
         FIG.  4    shows spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at long-focal-length end according to the 1st embodiment; 
         FIG.  5    is a schematic view of an image capturing unit at the short-focal-length end according to the 2nd embodiment of the present disclosure; 
         FIG.  6    is a schematic view of the image capturing unit at the long-focal-length end according to the 2nd embodiment of the present disclosure; 
         FIG.  7    shows spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at the short-focal-length end according to the 2nd embodiment; 
         FIG.  8    shows spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at long-focal-length end according to the 2nd embodiment; 
         FIG.  9    is a schematic view of an image capturing unit at the short-focal-length end according to the 3rd embodiment of the present disclosure; 
         FIG.  10    is a schematic view of the image capturing unit at the long-focal-length end according to the 3rd embodiment of the present disclosure; 
         FIG.  11    shows spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at the short-focal-length end according to the 3rd embodiment; 
         FIG.  12    shows spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at long-focal-length end according to the 3rd embodiment; 
         FIG.  13    is a schematic view of an image capturing unit at the short-focal-length end according to the 4th embodiment of the present disclosure; 
         FIG.  14    is a schematic view of the image capturing unit at the long-focal-length end according to the 4th embodiment of the present disclosure; 
         FIG.  15    shows spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at the short-focal-length end according to the 4th embodiment; 
         FIG.  16    shows spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at long-focal-length end according to the 4th embodiment; 
         FIG.  17    is a schematic view of an image capturing unit at the short-focal-length end according to the 5th embodiment of the present disclosure; 
         FIG.  18    is a schematic view of the image capturing unit at the long-focal-length end according to the 5th embodiment of the present disclosure; 
         FIG.  19    shows spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at the short-focal-length end according to the 5th embodiment; 
         FIG.  20    shows spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at long-focal-length end according to the 5th embodiment; 
         FIG.  21    is one perspective view of an electronic device according to the 6th embodiment of the present disclosure; 
         FIG.  22    is another perspective view of the electronic device in  FIG.  21   ; 
         FIG.  23    is a cross-sectional view of two image capturing units of the electronic device in  FIG.  21   ; 
         FIG.  24    is a perspective view of an electronic device according to the 7th embodiment of the present disclosure; 
         FIG.  25    shows a schematic view of Y11S, TDS, BLS, ImgHS, Y82S, and inflection points and a critical point of the eighth lens element according to the 1st embodiment of the present disclosure; 
         FIG.  26    shows a schematic view of Y11L, TDL, BLL, ImgHL, Y82L, TG1, TG2, TG3 and TG4 according to the 1st embodiment of the present disclosure; 
         FIG.  27    shows a schematic view of a configuration of a light-folding element in an image capturing lens system according to one embodiment of the present disclosure; 
         FIG.  28    shows a schematic view of another configuration of a light-folding element in an image capturing lens system according to one embodiment of the present disclosure; and 
         FIG.  29    shows a schematic view of a configuration of two light-folding elements in an image capturing lens system according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     An image capturing lens system includes four lens groups, and the four lens groups include eight lens elements. The four lens groups are, in order from an object side to an image side along an optical path, a first lens group, a second lens group, a third lens group and a fourth lens group. The eight lens elements are, in order from the object side to the image side along the optical path, 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. Each of the eight lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. For example, in one configuration, the first lens group includes the first lens element and the second lens element, the second lens group includes the third lens element, the fourth lens element and the fifth lens element, the third lens group includes the sixth lens element and the seventh lens element, and the fourth lens group includes the eighth lens element. 
     According to the present disclosure, the focal length of the image capturing lens system is varied by changing axial distances between the four lens groups in a zooming process, and the image capturing lens system has a long-focal-length end and a short-focal-length end. Therefore, the configuration of four lens groups and eight lens elements is favorable for increasing the zoom ratio and improving image quality. Please refer to  FIG.  1    and  FIG.  2   , which are schematic views of an image capturing unit respectively at the short-focal-length end and the long-focal-length end according to the 1st embodiment of the present disclosure. Moreover, there is no relative motion between lens elements of one lens group in the zooming process (e.g., there is no relative motion between the lens elements of the first lens group). Therefore, it is favorable for simplifying the structure of the image capturing lens system. 
     The first lens group includes at least one lens element. Moreover, in one configuration where the first lens group includes two lens elements, it is favorable for reducing the outer diameter at the object side of the image capturing lens system and obtaining a telephoto configuration in the image capturing lens system. Moreover, the first lens group can have negative refractive power. Therefore, it is favorable for increasing the zoom ratio. 
     The second lens group includes at least one lens element. Moreover, second lens group can include at least three lens elements. Therefore, it is favorable for providing consistent image quality in the zooming process. Moreover, in one configuration where the second lens group includes three lens elements, it is favorable for balancing among the zoom ratio, system size and image quality. Moreover, the second lens group is moved relative to the first lens group along an optical axis in the zooming process. Therefore, it is favorable for minimizing mechanical design restrictions of the image capturing lens system. Moreover, when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end, the second lens group can be moved along the optical axis toward the object side relative to the first lens group. Therefore, it is favorable for increasing the zoom ratio. In addition, when the image capturing lens system is zooming from the long-focal-length end to the short-focal-length end, the second lens group can be moved along the optical axis toward the image side relative to the first lens group. Moreover, the second lens group can have positive refractive power. Therefore, it is favorable for increasing the zoom ratio and reducing the outer diameter of the image capturing lens system. 
     The third lens group includes at least one lens element. Moreover, in one configuration where the third lens group includes two lens elements, it is favorable for providing consistent image quality during the zooming process. Moreover, the third lens group can be moved relative to the first lens group along the optical axis in the zooming process. Therefore, it is favorable for correcting aberrations generated during the zooming process and reducing the variation of back focal length. Moreover, the image capturing lens system can focus on an object in a focusing process as an object distance varies, and the third lens group can be moved relative to the first lens group along the optical axis in the focusing process. Therefore, it is favorable for reducing the movement of lens groups in the focusing process. Moreover, when the object distance decreases in the focusing process, the third lens group can be moved along the optical axis toward the image side relative to the first lens group. Therefore, it is favorable for correcting aberrations, such as field curvature, generated during the focusing process. Moreover, third lens group can have negative refractive power. Therefore, it is favorable for correcting aberrations generated during the zooming process. 
     The fourth lens group includes at least one lens element. Moreover, the fourth lens group can have positive refractive power. Therefore, it is favorable for adjusting the light path and the back focal length in the zooming process. 
     The refractive power of the first lens group and the refractive power of the second lens group can have opposite signs from each other, or the refractive power of the third lens group and the refractive power of the fourth lens group can have opposite signs from each other. Therefore, it is favorable for correcting aberrations generated during the zooming process. When the refractive power of one lens group and the refractive power of another lens group have opposite signs from each other, it means that one of the lens group has positive refractive power and the other has negative refractive power. 
     According to the present disclosure, the image capturing lens system further includes an aperture stop, and the aperture stop can be disposed in the second lens group. Therefore, it is favorable for adjusting the relative position of the aperture stop during the zooming process so as to balance the image quality at each focal length of the image capturing lens system. 
     At least one lens group of the image capturing lens system can be moved along the optical axis so as to compensate temperature effect. Therefore, it is favorable for reducing the influence of temperature change on the image quality, so that the image capturing lens system is applicable to more applications. Moreover, the third lens group can be moved along the optical axis so as to compensate temperature effect. Therefore, it is favorable for minimizing the movement of lens groups. 
     At least one lens element in the first lens group, the second lens group, the third lens group and the fourth lens group can be made of plastic material. Therefore, it is favorable for reducing the system size and weight and increasing image quality and mass production. Moreover, there can be at least two lens elements in the first, second, third and fourth lens groups being made of plastic material. Moreover, there can be at least three lens elements in the first, second, third and fourth lens groups being made of plastic material. Moreover, there can be at least four lens elements in the first, second, third and fourth lens groups being made of plastic material. 
     At least one lens element in the second lens group, the third lens group and the fourth lens group has at least one inflection point in an off-axis region thereof. Therefore, it is favorable for increasing the shape variation of the lens element so as to miniaturize the lens element and improve image quality. Moreover, there can be at least two lens elements in the second, third and fourth lens groups each having at least one inflection point in an off-axis region thereof. Moreover, there can be at least three lens elements in the second, third and fourth lens groups each having at least one inflection point in an off-axis region thereof. Moreover, there can be at least four lens elements in the second, third and fourth lens groups each having at least one inflection point in an off-axis region thereof. Please refer to  FIG.  25   , which shows a schematic view of the inflection points P of the eighth lens element  180  according to the 1st embodiment of the present disclosure. The inflection points of the eighth lens element in  FIG.  25    are only exemplary. In each embodiment, each of object-side surfaces and image-side surfaces of the lens elements can have one or more inflection points in an off-axis region thereof. 
     At least one lens element in the second lens group, the third lens group and the fourth lens group can have at least one critical point in an off-axis region thereof. Therefore, it is favorable for further increasing the shape variation of the lens element so as to miniaturize the image capturing lens system and correct aberrations. Moreover, there can be at least two lens elements in the second, third and fourth lens groups each having at least one critical point in an off-axis region thereof. Please refer to  FIG.  25   , which shows a schematic view of the critical point C of the eighth lens element  180  according to the 1st embodiment of the present disclosure. The critical point of the eighth lens element in  FIG.  25    is only exemplary. In each embodiment, each of object-side surfaces and image-side surfaces of the lens elements can have one or more critical points in an off-axis region thereof. 
     The first lens element has positive refractive power. Therefore, it is favorable for reducing the outer diameter at the object side of the image capturing lens system. 
     The second lens element has negative refractive power. Therefore, it is favorable for balancing the refractive power at the object side of the image capturing lens system so as to reduce aberrations such as spherical aberration. The image-side surface of the second lens element can be concave in a paraxial region thereof. Therefore, it is favorable for adjusting the surface shape and refractive power of the second lens element so as to correct aberrations such as astigmatism. 
     The third lens element can have positive refractive power. Therefore, it is favorable for increasing the zoom ratio. The object-side surface of the third lens element can be convex in a paraxial region thereof. Therefore, it is favorable for adjusting light travelling direction so as to reduce the outer diameter of the image capturing lens system. 
     The fourth lens element can have negative refractive power. Therefore, it is favorable for correcting aberrations generated during the zooming process. 
     The fifth lens element can have positive refractive power. Therefore, it is favorable for maintaining the system size in the zooming process. 
     The seventh lens element can have negative refractive power. Therefore, it is favorable for balancing the refractive power at the image side of the image capturing lens system so as to reduce aberrations. 
     The eighth lens element can have positive refractive power. Therefore, it is favorable for adjusting the back focal length. 
     When 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, 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, an Abbe number of one lens element of the image capturing lens system is Vi, a refractive index of the one lens element of the image capturing lens system is Ni, and a minimum value of Vi/Ni is (Vi/Ni) min, the following condition is satisfied: 7.5&lt;(Vi/Ni) min&lt;12.3, wherein i=1, 2, 3, 4, 5, 6, 7 or 8. Therefore, it is favorable for providing a proper lens material distribution of the image capturing lens system so as to reduce the system size and correct aberrations. 
     When half of a maximum field of view of the image capturing lens system at the short-focal-length end is HFOVS, the following condition is satisfied: 3.0 degrees&lt;HFOVS&lt;25.0 degrees. Therefore, it is favorable for adjusting the viewing angle at the short-focal-length end so as to obtain a telephoto configuration for various applications. Moreover, the following condition can also be satisfied: 7.0 degrees&lt;HFOVS&lt;20.0 degrees. Moreover, the following condition can also be satisfied: 10.0 degrees&lt;HFOVS&lt;15.0 degrees. 
     When a maximum distance between an optically effective area of the object-side surface of the first lens element and the optical axis when the image capturing lens system is at the long-focal-length end is Y11L, and a maximum distance between an optically effective area of the image-side surface of the eighth lens element and the optical axis when the image capturing lens system is at the long-focal-length end is Y82L, the following condition is satisfied: 0.50&lt;Y11L/Y82L&lt;2.0. Therefore, it is favorable for adjusting light travelling direction so as to balance among the field of view, zoom ratio and image quality in the zooming process. Moreover, the following condition can also be satisfied: 0.65&lt;Y11L/Y82L&lt;1.5. Moreover, the following condition can also be satisfied: 0.75&lt;Y11L/Y82L&lt;1.3. Please refer to  FIG.  26   , which shows a schematic view of Y11L and Y82L according to the 1st embodiment of the present disclosure. In addition, the image capturing lens system in  FIG.  26    is at the long-focal-length end. 
     When a maximum distance between an optically effective area of the object-side surface of the first lens element and the optical axis when the image capturing lens system is at the short-focal-length end is Y11S, and a maximum distance between an optically effective area of the image-side surface of the eighth lens element and the optical axis when the image capturing lens system is at the short-focal-length end is Y82S, the following condition is satisfied: 0.50&lt;Y11S/Y82S&lt;2.0. Therefore, it is favorable for adjusting light travelling direction so as to balance among the field of view, zoom ratio and image quality in the zooming process. Moreover, the following condition can also be satisfied: 0.65&lt;Y11S/Y82S&lt;1.5. Moreover, the following condition can also be satisfied: 0.75&lt;Y11S/Y82S&lt;1.3. Please refer to  FIG.  25   , which shows a schematic view of Y11S and Y82S according to the 1st embodiment of the present disclosure. In addition, the image capturing lens system in  FIG.  25    is at the short-focal-length end. 
     When an axial distance between the object-side surface of the first lens element and the image-side surface of the eighth lens element when the image capturing lens system is at the long-focal-length end is TDL, and an axial distance between the object-side surface of the first lens element and the image-side surface of the eighth lens element when the image capturing lens system is at the short-focal-length end is TDS, the following condition can be satisfied: |TDL/TDS−1|&lt;1.0E−2. Therefore, it is favorable for adjusting the lens elements distribution during the zooming process so as to simplify the structure of the image capturing lens system. Moreover, the following condition can also be satisfied: |TDL/TDS−1|&lt;5.0E−3. Moreover, the following condition can also be satisfied: |TDL/TDS−1|&lt;2.0E−3. Moreover, the following condition can also be satisfied: |TDL/TDS−1|&lt;1.0E−3. Please refer to  FIG.  25    and  FIG.  26   , which respectively show a schematic view of TDS and a schematic view of TDL according to the 1st embodiment of the present disclosure. 
     When a focal length of the image capturing lens system at the long-focal-length end is fL, and a focal length of the image capturing lens system at the short-focal-length end is fS, the following condition can be satisfied: 1.45&lt;fL/fS. Therefore, it is favorable for increasing the zoom ratio for more applications. Moreover, the following condition can also be satisfied: 1.95&lt;fL/fS. Moreover, the following condition can also be satisfied: 2.45&lt;fL/fS. Moreover, the following condition can also be satisfied: fL/fS&lt;4.45. Therefore, it is favorable for preventing the zoom ratio from being overly large so as to ensure compact system size and high image quality. Moreover, the following condition can also be satisfied: fL/fS&lt;3.50. Moreover, the following condition can also be satisfied: fL/fS&lt;3.10. Moreover, the following condition can also be satisfied: 1.45&lt;fL/fS&lt;3.50. 
     When a variation of axial distance between the first lens group and the second lens group when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end is dTG12, and an axial distance between a most object-side surface and a most image-side surface of the second lens group is TG2, the following condition can be satisfied: dTG12/TG2&lt;−0.80. Therefore, it is favorable for the first lens group and the second lens group to collaborate with each other during the zooming process so as to increase the zoom ratio. Moreover, the following condition can also be satisfied: −3.0&lt;dTG12/TG2&lt;−1.0. Please refer to  FIG.  26   , which shows a schematic view of TG2 according to the 1st embodiment of the present disclosure, wherein the most object-side surface of the second lens group G2 is the object-side surface  131  of the third lens element  130 , and the most image-side surface of the second lens group G2 is the image-side surface  152  of the fifth lens element  150 . 
     When a variation of axial distance between the third lens group and the fourth lens group when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end is dTG34, an axial distance between a most object-side surface and a most image-side surface of the third lens group is TG3, and an axial distance between a most object-side surface and a most image-side surface of the fourth lens group is TG4, the following condition can be satisfied: |dTG34|/(TG3+TG4)&lt;0.70. Therefore, it is favorable for the third lens group and the fourth lens group to collaborate with each other during the zooming process so as to correct aberrations generated during the zooming process. Please refer to  FIG.  26   , which shows a schematic view of TG3 and TG4 according to the 1st embodiment of the present disclosure. 
     When an axial distance between a most object-side surface and a most image-side surface of the first lens group is TG1, and the axial distance between the most object-side surface and the most image-side surface of the second lens group is TG2, the following condition can be satisfied: 0.80&lt;TG1/TG2&lt;1.4. Therefore, it is favorable for adjusting the lens elements distribution of the first and second lens groups so as to reduce the outer diameter at the object side of the image capturing lens system. Please refer to  FIG.  26   , which shows a schematic view of TG1 and TG2 according to the 1st embodiment of the present disclosure. 
     When the axial distance between the most object-side surface and the most image-side surface of the second lens group is TG2, and the axial distance between the most object-side surface and the most image-side surface of the third lens group is TG3, the following condition can be satisfied: 1.6&lt;TG2/TG3&lt;3.6. Therefore, it is favorable for adjusting the lens elements distribution so as to balance between the zoom ratio and the image quality. 
     When the axial distance between the object-side surface of the first lens element and the image-side surface of the eighth lens element when the image capturing lens system is at the long-focal-length end is TDL, and the focal length of the image capturing lens system at the long-focal-length end is fL, the following condition can be satisfied: 0.50&lt;TDL/fL&lt;1.3. Therefore, it is favorable for balancing between the system size and viewing angle at the long-focal-length end. Moreover, the following condition can also be satisfied: 0.70&lt;TDL/fL&lt;1.1. 
     When the maximum distance between the optically effective area of the object-side surface of the first lens element and the optical axis when the image capturing lens system is at the long-focal-length end is Y11L, and a maximum image height of the image capturing lens system at the long-focal-length end (which may be half of a diagonal length of an effective photosensitive area of an image sensor) is ImgHL, the following condition can be satisfied: 0.65&lt;Y11L/ImgHL&lt;1.5. Therefore, it is favorable for adjusting light travelling direction in the zooming process so as to reduce the outer diameter of the image capturing lens system and obtain a telephoto configuration. Moreover, the following condition can also be satisfied: 0.75&lt;Y11L/ImgHL&lt;1.3. Please refer to  FIG.  26   , which shows a schematic view of Y11L and ImgHL according to the 1st embodiment of the present disclosure. 
     When the maximum distance between the optically effective area of the object-side surface of the first lens element and the optical axis when the image capturing lens system is at the short-focal-length end is Y11S, and a maximum image height of the image capturing lens system at the short-focal-length end (which may be half of the diagonal length of the effective photosensitive area of the image sensor) is ImgHS, the following condition can be satisfied: 0.65&lt;Y11S/ImgHS&lt;1.5. Therefore, it is favorable for adjusting light travelling direction in the zooming process so as to reduce the outer diameter of the image capturing lens system and obtain a telephoto configuration. Moreover, the following condition can also be satisfied: 0.75&lt;Y11S/ImgHS&lt;1.3. Please refer to  FIG.  25   , which shows a schematic view of Y11S and ImgHS according to the 1st embodiment of the present disclosure. 
     When the Abbe number of the first lens element is V1, the Abbe number of the sixth lens element is V6, and the Abbe number of the eighth lens element is V8, the following condition can be satisfied: 30.0&lt;V1+V6+V8&lt;105.0. Therefore, a proper distribution of materials of the lens elements is favorable for correcting chromatic aberration. Moreover, the following condition can also be satisfied: 35.0&lt;V1+V6+V8&lt;85.0. Moreover, the following condition can also be satisfied: 40.0&lt;V1+V6+V8&lt;70.0. 
     When a focal length of the fourth lens element is f4, and a focal length of the fifth lens element is f5, the following condition can be satisfied: −1.0&lt;f4/f5&lt;−0.10. Therefore, it is favorable for balancing the refractive power distribution between the object side and the image side of the image capturing lens system so as to reduce the system size. 
     When the focal length of the image capturing lens system at the short-focal-length end is fS, and an entrance pupil diameter of the image capturing lens system at the short-focal-length end is EPDS, the following condition can be satisfied: 2.0&lt;fS/EPDS&lt;3.8. Therefore, it is favorable for balancing between the field of view and aperture size of the image capturing lens system at the short-focal-length end. Moreover, the following condition can also be satisfied: 2.5&lt;fS/EPDS&lt;3.5. 
     When the focal length of the image capturing lens system at the short-focal-length end is fS, a focal length of the first lens group is fG1, a focal length of the second lens group is fG2, a focal length of the third lens group is fG3, and a focal length of the fourth lens group is fG4, at least one of the following conditions can be satisfied: −1.5&lt;fS/fG1&lt;0; 1.0&lt;fS/fG2&lt;2.0; −1.2&lt;fS/fG3&lt;−0.50; or 0.30&lt;fS/fG4&lt;1.5. Therefore, it is favorable for adjusting the refractive power distribution of the image capturing lens system at the short-focal-length end so as to balance among the system size, field of view and image quality. Moreover, the following condition can also be satisfied: −1.0&lt;fS/fG1&lt;−0.55. Said focal length of one lens group is a composite focal length of all lens elements in the lens group. 
     When an axial distance between the image-side surface of the eighth lens element and an image surface when the image capturing lens system is at the long-focal-length end is BLL, and an axial distance between the image-side surface of the eighth lens element and the image surface when the image capturing lens system is at the short-focal-length end is BLS, the following condition can be satisfied: |BLL/BLS−1|&lt;5.0E−2. Therefore, it is favorable for preventing the incident angle of light on the image surface from overly varying in the zooming process. Moreover, the following condition can also be satisfied: |BLL/BLS−1|&lt;3.0E−2. Moreover, the following condition can also be satisfied: |BLL/BLS−1|&lt;1.0E−2. Please refer to  FIG.  25    and  FIG.  26   , which respectively show a schematic view of BLS and a schematic view of BLL according to the 1st embodiment of the present disclosure. 
     When the axial distance between the most object-side surface and the most image-side surface of the third lens group is TG3, and the axial distance between the most object-side surface and the most image-side surface of the fourth lens group is TG4, the following condition can be satisfied: 0.35&lt;TG3/TG4&lt;3.0. Therefore, it is favorable for correcting aberrations generated during the zooming process and reducing the variation of back focal length. Moreover, the following condition can also be satisfied: 0.50&lt;TG3/TG4&lt;2.0. 
     When a focal length of the first lens element is f1, and a focal length of the third lens element is f3, the following condition can be satisfied: 0.60&lt;f1/f3&lt;6.0. Therefore, it is favorable for adjusting the refractive power distribution at the object side of the image capturing lens system so as to reduce the system size. Moreover, the following condition can also be satisfied: 1.0&lt;f1/f3&lt;3.0. 
     When half of a maximum field of view of the image capturing lens system at the long-focal-length end is HFOVL, the following condition can be satisfied: 3.0 degrees&lt;HFOVL&lt;10.0 degrees. Therefore, it is favorable for adjusting the field of view of the image capturing lens system at the long-focal-length end so as to obtain a telephoto configuration for various applications. 
     When the focal length of the first lens group is fG1, and the focal length of the second lens group is fG2, the following condition can be satisfied: −2.5&lt;fG1/fG2&lt;−1.5. Therefore, it is favorable for adjusting the refractive power distribution so as to increase zoom ratio. 
     When the focal length of the third lens group is fG3, and the focal length of the fourth lens group is fG4, the following condition can be satisfied: −1.2&lt;fG3/fG4&lt;−0.50. Therefore, it is favorable for adjusting the refractive power distribution so as to correct aberrations generated during the zooming process. 
     When the variation of axial distance between the first lens group and the second lens group when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end is dTG12, and a variation of axial distance between the second lens group and the third lens group when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end is dTG23, the following condition can be satisfied: −2.0&lt;dTG12/dTG23&lt;−0.50. Therefore, it is favorable for increasing the zoom ratio and ensuring consistent image quality in the zooming process. Moreover, the following condition can also be satisfied: −1.5&lt;dTG12/dTG23&lt;−0.70. Moreover, the following condition can also be satisfied: −1.2&lt;dTG12/dTG23&lt;−0.85. 
     According to the present disclosure, the aforementioned features and conditions can be utilized in numerous combinations so as to achieve corresponding effects. 
     According to the present disclosure, the lens elements of the image capturing lens system can be made of either glass or plastic material. When the lens elements are made of glass material, the refractive power distribution of the image capturing lens system may be more flexible, and the influence on imaging caused by external environment temperature change may be reduced. The glass lens element can either be made by grinding or molding. When the lens elements are made of plastic material, the manufacturing costs can be effectively reduced. Furthermore, surfaces of each lens element can be arranged to be spherical or aspheric. Spherical lens elements are simple in manufacture. Aspheric lens element design allows more control variables for eliminating aberrations thereof and reducing the required number of lens elements, and the total track length of the image capturing lens system can therefore be effectively shortened. Additionally, the aspheric surfaces may be formed by plastic injection molding or glass molding. 
     According to the present disclosure, when a lens surface is aspheric, it means that the lens surface has an aspheric shape throughout its optically effective area, or a portion(s) thereof. 
     According to the present disclosure, one or more of the lens elements&#39; material may optionally include an additive which alters the lens elements&#39; transmittance in a specific range of wavelength for a reduction in unwanted stray light or colour deviation. For example, the additive may optionally filter out light in the wavelength range of 600 nm to 800 nm to reduce excessive red light and/or near infrared light; or may optionally filter out light in the wavelength range of 350 nm to 450 nm to reduce excessive blue light and/or near ultraviolet light from interfering the final image. The additive may be homogeneously mixed with a plastic material to be used in manufacturing a mixed-material lens element by injection molding. 
     According to the present disclosure, each of an object-side surface and an image-side surface has a paraxial region and an off-axis region. The paraxial region refers to the region of the surface where light rays travel close to the optical axis, and the off-axis region refers to the region of the surface away from the paraxial region. Particularly, unless otherwise stated, when the lens element has a convex surface, it indicates that the surface is convex in the paraxial region thereof; when the lens element has a concave surface, it indicates that the surface is concave in the paraxial region thereof. Moreover, when a region of refractive power or focus of a lens element is not defined, it indicates that the region of refractive power or focus of the lens element is in the paraxial region thereof. 
     According to the present disclosure, an inflection point is a point on the surface of the lens element at which the surface changes from concave to convex, or vice versa. A critical point is a non-axial point of the lens surface where its tangent is perpendicular to the optical axis. 
     According to the present disclosure, the image surface of the image capturing lens system, based on the corresponding image sensor, can be flat or curved, especially a curved surface being concave facing towards the object side of the image capturing lens system. 
     According to the present disclosure, an image correction unit, such as a field flattener, can be optionally disposed between the lens element closest to the image side of the image capturing lens system along the optical path and the image surface for correction of aberrations such as field curvature. The optical properties of the image correction unit, such as curvature, thickness, index of refraction, position and surface shape (convex or concave surface with spherical, aspheric, diffractive or Fresnel types), can be adjusted according to the design of the image capturing unit. In general, a preferable image correction unit is, for example, a thin transparent element having a concave object-side surface and a planar image-side surface, and the thin transparent element is disposed near the image surface. 
     According to the present disclosure, at least one light-folding element can be optionally disposed between an imaged object and the image surface on the imaging optical path, such that the image capturing lens system can be more flexible in space arrangement, and therefore the dimensions of an electronic device is not restricted by the total track length of the image capturing lens system. Moreover, the at least one light-folding element can be disposed on the object side of the first lens element. Moreover, the at least one light-folding element can include at least one reflection mirror. Moreover, the at least one light-folding element can include at least one prism. Moreover, the prism can have refractive power, and the surface of the prism can include a non-planar surface, such as spherical surface, aspheric surface, concave surface or convex surface. Therefore, it is favorable for improving image quality. Specifically, please refer to  FIG.  27    and  FIG.  28   .  FIG.  27    shows a schematic view of a configuration of a light-folding element in an image capturing lens system according to one embodiment of the present disclosure, and  FIG.  28    shows a schematic view of another configuration of a light-folding element in an image capturing lens system according to one embodiment of the present disclosure. In  FIG.  27    and  FIG.  28   , the image capturing lens system can have, in order from an imaged object (not shown in figure) to an image surface IM along an optical path, a first optical axis OA1, a light-folding element LF and a second optical axis OA2. The light-folding element LF can be disposed between the imaged object and a lens group LG of the image capturing lens system as shown in  FIG.  27    or disposed between a lens group LG of the image capturing lens system and the image surface IM as shown in  FIG.  28   . Furthermore, please refer to  FIG.  29   , which shows a schematic view of a configuration of two light-folding elements in an image capturing lens system according to one embodiment of the present disclosure. In  FIG.  29   , the image capturing lens system can have, in order from an imaged object (not shown in figure) to an image surface IM along an optical path, a first optical axis OA1, a first light-folding element LF1, a second optical axis OA2, a second light-folding element LF2 and a third optical axis OA3. The first light-folding element LF1 is disposed between the imaged object and a lens group LG of the image capturing lens system, and the second light-folding element LF2 is disposed between the lens group LG of the image capturing lens system and the image surface IM. The image capturing lens system can be optionally provided with three or more light-folding elements, and the present disclosure is not limited to the type, amount and position of the light-folding elements of the embodiments disclosed in the aforementioned figures. 
     According to the present disclosure, the image capturing lens system can include at least one stop, such as an aperture stop, a glare stop or a field stop. Said glare stop or said field stop is set for eliminating the stray light and thereby improving image quality thereof. 
     According to the present disclosure, an aperture stop can be configured as a front stop or a middle stop. A front stop disposed between an imaged object and the first lens element can provide a longer distance between an exit pupil of the image capturing lens system and the image surface to produce a telecentric effect, and thereby improves the image-sensing efficiency of an image sensor (for example, CCD or CMOS). A middle stop disposed between the first lens element and the image surface is favorable for enlarging the viewing angle of the image capturing lens system and thereby provides a wider field of view for the same. 
     According to the present disclosure, the image capturing lens system can include an aperture control unit. The aperture control unit may be a mechanical component or a light modulator, which can control the size and shape of the aperture through electricity or electrical signals. The mechanical component can include a movable member, such as a blade assembly or a light shielding sheet. The light modulator can include a shielding element, such as a filter, an electrochromic material or a liquid-crystal layer. The aperture control unit controls the amount of incident light or exposure time to enhance the capability of image quality adjustment. In addition, the aperture control unit can be the aperture stop of the present disclosure, which changes the f-number to obtain different image effects, such as the depth of field or lens speed. 
     According to the present disclosure, the object side and image side are defined in accordance with the direction of the optical axis, and the axial optical data are calculated along the optical axis. Furthermore, if the optical axis is folded by a light-folding element, the axial optical data are also calculated along the folded optical axis. 
     According to the above description of the present disclosure, the following specific embodiments are provided for further explanation. 
     1st Embodiment 
       FIG.  1    is a schematic view of an image capturing unit at the short-focal-length end according to the 1st embodiment of the present disclosure.  FIG.  2    is a schematic view of the image capturing unit at the long-focal-length end according to the 1st embodiment of the present disclosure.  FIG.  3    shows, in order from left to right, spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at the short-focal-length end according to the 1st embodiment.  FIG.  4    shows, in order from left to right, spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at long-focal-length end according to the 1st embodiment. In  FIG.  1    and  FIG.  2   , the image capturing unit includes the image capturing lens system (its reference numeral is omitted) of the present disclosure and an image sensor  199 . The image capturing lens system includes, in order from an object side to an image side along an optical path, a stop  101 , a first lens element  110 , a second lens element  120 , a third lens element  130 , an aperture stop  100 , a fourth lens element  140 , a fifth lens element  150 , a sixth lens element  160 , a seventh lens element  170 , an eighth lens element  180 , a filter  190  and an image surface  195 . In addition, the image capturing lens system has a configuration of a first lens group G1 (including the first lens element  110  and the second lens element  120 ), a second lens group G2 (including the third lens element  130 , the aperture stop  100 , the fourth lens element  140  and the fifth lens element  150 ), a third lens group G3 (including the sixth lens element  160  and the seventh lens element  170 ) and a fourth lens group G4 (including the eighth lens element  180 ). The first lens group G1 has negative refractive power, the second lens group G2 has positive refractive power, the third lens group G3 has negative refractive power, and the fourth lens group G4 has positive refractive power. The image capturing lens system includes eight lens elements ( 110 ,  120 ,  130 ,  140 ,  150 ,  160 ,  170  and  180 ) with no additional lens element disposed between each of the adjacent eight lens elements. 
     The focal length of the image capturing lens system is varied by changing axial distances between the four lens groups (G1, G2, G3 and G4) in a zooming process. As shown in  FIG.  1    and  FIG.  2   , the second lens group G2 is moved relative to the first lens group G1 along an optical axis in the zooming process, and the third lens group G3 is moved relative to the first lens group G1 along the optical axis in the zooming process. Furthermore, the image capturing lens system has a short-focal-length end as shown in  FIG.  1    and a long-focal-length end as shown in  FIG.  2   . In addition, when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end, the second lens group G2 is moved along the optical axis toward the object side relative to the first lens group G1. It is noted that there is no relative motion between lens elements of each of the four lens groups in the zooming process. 
     The first lens element  110  with positive refractive power has an object-side surface  111  being convex in a paraxial region thereof and an image-side surface  112  being convex in a paraxial region thereof. The first lens element  110  is made of plastic material and has the object-side surface  111  and the image-side surface  112  being both aspheric. 
     The second lens element  120  with negative refractive power has an object-side surface  121  being convex in a paraxial region thereof and an image-side surface  122  being concave in a paraxial region thereof. The second lens element  120  is made of plastic material and has the object-side surface  121  and the image-side surface  122  being both aspheric. 
     The third lens element  130  with positive refractive power has an object-side surface  131  being convex in a paraxial region thereof and an image-side surface  132  being convex in a paraxial region thereof. The third lens element  130  is made of glass material and has the object-side surface  131  and the image-side surface  132  being both aspheric. The third lens element  130  has at least one inflection point in an off-axis region thereof. 
     The fourth lens element  140  with negative refractive power has an object-side surface  141  being concave in a paraxial region thereof and an image-side surface  142  being convex in a paraxial region thereof. The fourth lens element  140  is made of plastic material and has the object-side surface  141  and the image-side surface  142  being both aspheric. The fourth lens element  140  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The fifth lens element  150  with positive refractive power has an object-side surface  151  being concave in a paraxial region thereof and an image-side surface  152  being convex in a paraxial region thereof. The fifth lens element  150  is made of plastic material and has the object-side surface  151  and the image-side surface  152  being both aspheric. The fifth lens element  150  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The sixth lens element  160  with positive refractive power has an object-side surface  161  being convex in a paraxial region thereof and an image-side surface  162  being concave in a paraxial region thereof. The sixth lens element  160  is made of plastic material and has the object-side surface  161  and the image-side surface  162  being both aspheric. 
     The seventh lens element  170  with negative refractive power has an object-side surface  171  being concave in a paraxial region thereof and an image-side surface  172  being concave in a paraxial region thereof. The seventh lens element  170  is made of plastic material and has the object-side surface  171  and the image-side surface  172  being both aspheric. The seventh lens element  170  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The eighth lens element  180  with positive refractive power has an object-side surface  181  being convex in a paraxial region thereof and an image-side surface  182  being concave in a paraxial region thereof. The eighth lens element  180  is made of plastic material and has the object-side surface  181  and the image-side surface  182  being both aspheric. The eighth lens element  180  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The filter  190  is made of glass material and located between the eighth lens element  180  and the image surface  195 , and will not affect the focal length of the image capturing lens system. The image sensor  199  is disposed on or near the image surface  195 . 
     The equation of the aspheric surface profiles of the aforementioned lens elements of the 1st embodiment is expressed as follows: 
                 X   ⁡     (   Y   )       =         (       Y   2     /   R     )     /     (     1   +     s   ⁢   q   ⁢   r   ⁢     t   ⁡     (     1   -       (     1   +   k     )     ×       (     Y   /   R     )     2         )           )       +       ∑   i     ⁢       (   Ai   )     ×     (     Y   i     )             ,         
where,
 
     X is a displacement in parallel with an optical axis from an axial vertex on the aspheric surface to a point at a distance of Y from the optical axis on the aspheric surface; 
     Y is the vertical distance from the point on the aspheric surface to the optical axis; 
     R is the curvature radius; 
     k is the conic coefficient; and 
     Ai is the i-th aspheric coefficient, and in the embodiments, i may be, but is not limited to, 4, 6, 8, 10, 12, 14 and 16. 
     In the image capturing lens system of the image capturing unit according to the 1st embodiment, a focal length of the image capturing lens system is f, an f-number of the image capturing lens system is Fno, half of a maximum field of view of the image capturing lens system is HFOV, an axial distance between an imaged object and the stop  101  is D0, an axial distance between the first lens group G1 and the second lens group G2 is D5, an axial distance between the second lens group G2 and the third lens group G3 is D12, and an axial distance between the third lens group G3 and the fourth lens group G4 is D16. With different focusing conditions, the aforementioned parameters may have different values. In this embodiment, two of various focusing states of the image capturing lens system according to different focusing conditions are provided (i.e., different object distances). A first focusing state of the image capturing lens system is a state where the image capturing lens system focuses on an imaged object located at infinity, and a second focusing state of the image capturing lens system is a state where the image capturing lens system focuses on an imaged object located at a finite distance. 
     Furthermore, in each focusing state, some of the aforementioned parameters have different values when the image capturing lens system is at the short-focal-length end or at the long-focal-length end. Specifically, a focal length of the image capturing lens system at the short-focal-length end is fS, a focal length of the image capturing lens system at the long-focal-length end is fL, an f-number of the image capturing lens system at the short-focal-length end is FnoS, an f-number of the image capturing lens system at the long-focal-length end is FnoL, half of a maximum field of view of the image capturing lens system at the short-focal-length end is HFOVS, and half of a maximum field of view of the image capturing lens system at the long-focal-length end is HFOVL. 
     Note that  FIG.  1    shows the image capturing lens system at the short-focal-length end in the first focusing state, and  FIG.  2    shows the image capturing lens system at the long-focal-length end in the first focusing state. 
     In the first focusing state, when the image capturing lens system is at the short-focal-length end, the aforementioned parameters have the following values: fS=7.49 millimeters (mm), FnoS=3.21, HFOVS=13.8 degrees (deg.), D0=∞ (infinity), D5=5.432 mm, D12=1.803 mm, and D16=3.493 mm. 
     In the first focusing state, when the image capturing lens system is at the long-focal-length end, the aforementioned parameters have the following values: fL=18.75 mm, FnoL=5.16, HFOVL=5.5 degrees, D0=∞, D5=0.424 mm, D12=6.688 mm, and D16=3.616 mm. 
     When an Abbe number of the first lens element  110  is V1, an Abbe number of the second lens element  120  is V2, an Abbe number of the third lens element  130  is V3, an Abbe number of the fourth lens element  140  is V4, an Abbe number of the fifth lens element  150  is V5, an Abbe number of the sixth lens element  160  is V6, an Abbe number of the seventh lens element  170  is V7, an Abbe number of the eighth lens element  180  is V8, an Abbe number of the i-th lens element is Vi, a refractive index of the first lens element  110  is N1, a refractive index of the second lens element  120  is N2, a refractive index of the third lens element  130  is N3, a refractive index of the fourth lens element  140  is N4, a refractive index of the fifth lens element  150  is N5, a refractive index of the sixth lens element  160  is N6, a refractive index of the seventh lens element  170  is N7, a refractive index of the eighth lens element  180  is N8, a refractive index of the i-th lens element is Ni, and a minimum value of Vi/Ni is (Vi/Ni) min, the following condition is satisfied: (Vi/Ni) min=8.70, wherein i=1, 2, 3, 4, 5, 6, 7 or 8. In this embodiment, among the first through eighth lens elements ( 110 - 180 ), a ratio of the Abbe number and the refractive index of the sixth lens element  160  is smaller than that of the other lens elements, and (Vi/Ni) min is equal to the ratio of the Abbe number and the refractive index of the sixth lens element  160 . 
     When the Abbe number of the first lens element  110  is V1, the Abbe number of the sixth lens element  160  is V6, and the Abbe number of the eighth lens element  180  is V8, the following condition is satisfied: V1+V6+V8=52.6. 
     When an axial distance between the object-side surface  111  of the first lens element  110  and the image-side surface  182  of the eighth lens element  180  when the image capturing lens system is at the long-focal-length end is TDL, and the focal length of the image capturing lens system at the long-focal-length end is fL, the following condition is satisfied: TDL/fL=0.92. 
     When an axial distance between the image-side surface  182  of the eighth lens element  180  and the image surface  195  when the image capturing lens system is at the long-focal-length end is BLL, and an axial distance between the image-side surface  182  of the eighth lens element  180  and the image surface  195  when the image capturing lens system is at the short-focal-length end is BLS, the following condition is satisfied: |BLL/BLS−1|=0.00E+00. 
     When a variation of axial distance between the third lens group G3 and the fourth lens group G4 when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end is dTG34, an axial distance between a most object-side surface and a most image-side surface of the third lens group G3 is TG3, and an axial distance between a most object-side surface and a most image-side surface of the fourth lens group G4 is TG4, the following condition is satisfied: |dTG34|/(TG3+TG4)=0.07. In this embodiment, dTG34=3.616-3.493=0.123 (mm). 
     When the axial distance between the object-side surface  111  of the first lens element  110  and the image-side surface  182  of the eighth lens element  180  when the image capturing lens system is at the long-focal-length end is TDL, and an axial distance between the object-side surface  111  of the first lens element  110  and the image-side surface  182  of the eighth lens element  180  when the image capturing lens system is at the short-focal-length end is TDS, the following condition is satisfied: |TDL/TDS−1|=0.00E+00. 
     When a variation of axial distance between the first lens group G1 and the second lens group G2 when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end is dTG12, and a variation of axial distance between the second lens group G2 and the third lens group G3 when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end is dTG23, the following condition is satisfied: dTG12/dTG23=−1.03. In this embodiment, dTG12=0.424−5.432=−5.008 (mm), and dTG23=6.688−1.803=4.885 (mm). 
     When the variation of axial distance between the first lens group G1 and the second lens group G2 when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end is dTG12, and an axial distance between a most object-side surface and a most image-side surface of the second lens group G2 is TG2, the following condition is satisfied: dTG12/TG2=−2.38. 
     When an axial distance between a most object-side surface and a most image-side surface of the first lens group G1 is TG1, and the axial distance between the most object-side surface and the most image-side surface of the second lens group G2 is TG2, the following condition is satisfied: TG1/TG2=1.21. 
     When the axial distance between the most object-side surface and the most image-side surface of the second lens group G2 is TG2, and the axial distance between the most object-side surface and the most image-side surface of the third lens group G3 is TG3, the following condition is satisfied: TG2/TG3=1.84. 
     When the axial distance between the most object-side surface and the most image-side surface of the third lens group G3 is TG3, and the axial distance between the most object-side surface and the most image-side surface of the fourth lens group G4 is TG4, the following condition is satisfied: TG3/TG4=1.66. 
     When a focal length of the first lens element  110  is f1, and a focal length of the third lens element  130  is f3, the following condition is satisfied: f1/f3=2.19. 
     When a focal length of the fourth lens element  140  is f4, and a focal length of the fifth lens element  150  is f5, the following condition is satisfied: f4/f5=−0.52. 
     When a focal length of the first lens group G1 is fG1, and a focal length of the second lens group G2 is fG2, the following condition is satisfied: fG1/fG2=−1.84. 
     When a focal length of the third lens group G3 is fG3, and a focal length of the fourth lens group G4 is fG4, the following condition is satisfied: fG3/fG4=−0.87. 
     When the focal length of the image capturing lens system at the long-focal-length end is fL, and the focal length of the image capturing lens system at the short-focal-length end is fS, the following condition is satisfied: fL/fS=2.50. 
     When the focal length of the image capturing lens system at the short-focal-length end is fS, and an entrance pupil diameter of the image capturing lens system at the short-focal-length end is EPDS, the following condition is satisfied: fS/EPDS=3.21. 
     When the focal length of the image capturing lens system at the short-focal-length end is fS, the focal length of the first lens group G1 is fG1, the focal length of the second lens group G2 is fG2, the focal length of the third lens group G3 is fG3, and the focal length of the fourth lens group G4 is fG4, the following conditions are satisfied: fS/fG1=−0.77; fS/fG2=1.42; fS/fG3=−0.71; and fS/fG4=0.62. 
     When half of the maximum field of view of the image capturing lens system at the long-focal-length end is HFOVL, the following condition is satisfied: HFOVL=5.5 degrees. 
     When half of the maximum field of view of the image capturing lens system at the short-focal-length end is HFOVS, the following condition is satisfied: HFOVS=13.8 degrees. 
     When a maximum distance between an optically effective area of the object-side surface  111  of the first lens element  110  and the optical axis when the image capturing lens system is at the long-focal-length end is Y11L, and a maximum image height of the image capturing lens system at the long-focal-length end is ImgHL, the following condition is satisfied: Y11L/ImgHL=1.16. 
     When the maximum distance between the optically effective area of the object-side surface  111  of the first lens element  110  and the optical axis when the image capturing lens system is at the long-focal-length end is Y11L, and a maximum distance between an optically effective area of the image-side surface  182  of the eighth lens element  180  and the optical axis when the image capturing lens system is at the long-focal-length end is Y82L, the following condition is satisfied: Y11L/Y82L=1.08. 
     When a maximum distance between an optically effective area of the object-side surface  111  of the first lens element  110  and the optical axis when the image capturing lens system is at the short-focal-length end is Y11S, and a maximum image height of the image capturing lens system at the short-focal-length end is ImgHS, the following condition is satisfied: Y11S/ImgHS=1.21. 
     When the maximum distance between the optically effective area of the object-side surface  111  of the first lens element  110  and the optical axis when the image capturing lens system is at the short-focal-length end is Y11S, and a maximum distance between an optically effective area of the image-side surface  182  of the eighth lens element  180  and the optical axis when the image capturing lens system is at the short-focal-length end is Y82S, the following condition is satisfied: Y11S/Y82S=1.13. 
     The detailed optical data of the 1st embodiment are shown in Table 1 and Table 2, and the aspheric surface data are shown in Table 3 below. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 1st Embodiment 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Focal Length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 D0  
                   
               
               
                 1 
                 Stop 
                 Plano 
                 −0.490  
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 2 
                 Lens 1 
                 6.370 
                 (ASP) 
                 1.500 
                 Plastic 
                 1.669 
                 19.5 
                 8.56 
               
               
                 3 
                   
                 −51.502 
                 (ASP) 
                 0.485 
               
               
                 4 
                 Lens 2 
                 263.154 
                 (ASP) 
                 0.559 
                 Plastic 
                 1.582 
                 30.2 
                 −3.67 
               
               
                 5 
                   
                 2.120 
                 (ASP) 
                 D5  
               
               
                 6 
                 Lens 3 
                 3.210 
                 (ASP) 
                 1.050 
                 Glass 
                 1.542 
                 62.9 
                 3.91 
               
               
                 7 
                   
                 −5.536 
                 (ASP) 
                 −0.132  
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 Ape. Stop 
                 Plano 
                 0.162 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 9 
                 Lens 4 
                 −4.267 
                 (ASP) 
                 0.300 
                 Plastic 
                 1.614 
                 26.0 
                 −7.14 
               
               
                 10 
                   
                 −163.820 
                 (ASP) 
                 0.182 
               
               
                 11 
                 Lens 5 
                 −500.000 
                 (ASP) 
                 0.544 
                 Plastic 
                 1.529 
                 58.0 
                 13.75 
               
               
                 12 
                   
                 −7.171 
                 (ASP) 
                 D12 
               
               
                 13 
                 Lens 6 
                 6.344 
                 (ASP) 
                 0.675 
                 Plastic 
                 1.701 
                 14.8 
                 19.33 
               
               
                 14 
                   
                 11.406 
                 (ASP) 
                 0.170 
               
               
                 15 
                 Lens 7 
                 −4.584 
                 (ASP) 
                 0.300 
                 Plastic 
                 1.614 
                 26.0 
                 −6.47 
               
               
                 16 
                   
                 30.485 
                 (ASP) 
                 D16 
               
               
                 17 
                 Lens 8 
                 4.706 
                 (ASP) 
                 0.691 
                 Plastic 
                 1.686 
                 18.4 
                 12.11 
               
               
                 18 
                   
                 10.204 
                 (ASP) 
                 0.500 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 19 
                 Filter 
                 Plano 
                 0.210 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 20 
                   
                 Plano 
                 2.077 
               
               
                 21 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm (d-line). 
               
               
                 An effective radius of the stop 101 (Surface 1) is 2.200 mm. 
               
            
           
         
       
     
     In Table 1, the curvature radius, the thickness and the focal length are shown in millimeters (mm). Surface numbers 0-21 represent the surfaces sequentially arranged from the object side to the image side along the optical axis. 
     The rest optical data of the image capturing lens system, including in the second focusing state, are disclosed in Table 2 below. Also, the definitions of the parameters shown in Table 2 are consistent with those stated in the first focusing state. In addition, it can be known from Table 2 that when the object distance decreases in the focusing process (e.g., from the first focusing state to the second focusing state), the axial distance between the first lens group G1 and the third lens group G3 increases from 9.341 mm (at short-focal-length end) and 9.218 mm (at long-focal-length end) of the first focusing state to 9.401 mm (at short-focal-length end) and 9.584 mm (at long-focal-length end) of the second focusing state; that is, when the object distance decreases in the focusing process, the third lens group G3 is moved along the optical axis toward the image side relative to the first lens group G1 in the focusing process. 
     
       
         
           
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 1st Embodiment 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Short-focal-length End 
                 Long-focal-length End 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 First Focusing State 
                   
               
            
           
           
               
               
               
               
            
               
                   
                 f [mm] 
                 7.49 
                 18.75 
               
               
                   
                 Fno 
                 3.21 
                 5.16 
               
               
                   
                 HFOV [deg.] 
                 13.8 
                 5.5 
               
               
                   
                 D0 [mm] 
                 ∞ 
                 ∞ 
               
               
                   
                 D5 [mm] 
                 5.432 
                 0.424 
               
               
                   
                 D12 [mm] 
                 1.803 
                 6.688 
               
               
                   
                 D16 [mm] 
                 3.493 
                 3.616 
               
            
           
           
               
               
               
            
               
                   
                 Second Focusing State 
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Fno 
                 3.21 
                 5.14 
               
               
                   
                 HFOV [deg.] 
                 13.8 
                 5.5 
               
               
                   
                 D0 [mm] 
                 1000.000 
                 1000.000 
               
               
                   
                 D5 [mm] 
                 5.432 
                 0.424 
               
               
                   
                 D12 [mm] 
                 1.863 
                 7.054 
               
               
                   
                 D16 [mm] 
                 3.432 
                 3.250 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 (Vi/Ni)min 
                 8.70 
                 fG3/fG4 
                 −0.87 
               
               
                   
                 V1 + V6 + V8 
                 52.6 
                 fL/fS 
                 2.50 
               
               
                   
                 TDL/fL 
                 0.92 
                 fS/EPDS 
                 3.21 
               
               
                   
                 |BLL/BLS − 1| 
                 0.00E+00 
                 fS/fG1 
                 −0.77 
               
               
                   
                 |dTG34|/(TG3 + TG4) 
                 0.07 
                 fS/fG2 
                 1.42 
               
               
                   
                 |TDL/TDS − 1| 
                 0.00E+00 
                 fS/fG3 
                 −0.71 
               
               
                   
                 dTG12/dTG23 
                 −1.03 
                 fS/fG4 
                 0.62 
               
               
                   
                 dTG12/TG2 
                 −2.38 
                 HFOVL [deg.] 
                 5.5 
               
               
                   
                 TG1/TG2 
                 1.21 
                 HFOVS [deg.] 
                 13.8 
               
               
                   
                 TG2/TG3 
                 1.84 
                 Y11L/ImgHL 
                 1.16 
               
               
                   
                 TG3/TG4 
                 1.66 
                 Y11L/Y82L 
                 1.08 
               
               
                   
                 f1/f3 
                 2.19 
                 Y11S/ImgHS 
                 1.21 
               
               
                   
                 f4/f5 
                 −0.52 
                 Y11S/Y82S 
                 1.13 
               
               
                   
                 fG1/fG2 
                 −1.84 
                 — 
                 — 
               
               
                   
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Aspheric Coefficients 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Surface # 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
               
               
                   
               
               
                 k = 
                 2.8650E+00 
                 −9.0000E+01  
                  4.5071E+01 
                 −5.7401E+00 
                 −1.1511E+01 
                 0.0000E+00 
               
               
                 A4 = 
                 3.8184E−03 
                 1.6754E−02 
                 −4.2422E−02 
                 −8.7581E−03 
                  4.1829E−02 
                 1.1687E−02 
               
               
                 A6 = 
                 −5.2209E−04  
                 −9.0875E−03  
                 −1.5090E−03 
                 −9.0931E−03 
                 −1.8383E−02 
                 6.6917E−03 
               
               
                 A8 = 
                 9.7466E−05 
                 4.1213E−03 
                  1.0686E−02 
                  1.3699E−02 
                  7.7725E−03 
                 −8.0603E−03  
               
               
                 A10 = 
                 3.3665E−05 
                 −8.0999E−04  
                 −5.3013E−03 
                 −7.3405E−03 
                 −2.8920E−03 
                 2.1062E−03 
               
               
                 A12 = 
                 −1.0003E−05  
                 4.0344E−05 
                  1.1671E−03 
                  1.8790E−03 
                  6.3204E−04 
                 −1.8451E−04  
               
               
                 A14 = 
                 9.7957E−07 
                 8.1343E−06 
                 −9.9563E−05 
                 −1.9151E−04 
                 −7.7254E−05 
                 −5.9301E−06  
               
               
                   
               
               
                 Surface # 
                 9 
                 10 
                 11 
                 12 
                 13 
                 14 
               
               
                   
               
               
                 k = 
                 0.0000E+00 
                 0.0000E+00 
                  0.0000E+00 
                 0.0000E+00 
                  1.7737E+00 
                 0.0000E+00 
               
               
                 A4 = 
                 4.2516E−02 
                 2.9888E−02 
                 −7.7799E−03 
                 6.3750E−04 
                 −3.1334E−03 
                 2.0093E−03 
               
               
                 A6 = 
                 −3.0640E−03  
                 6.4669E−03 
                  2.4166E−02 
                 7.9520E−03 
                 −3.7873E−03 
                 −5.3737E−03  
               
               
                 A8 = 
                 −3.0546E−03  
                 −9.4860E−03  
                 −2.0810E−02 
                 −6.4587E−03  
                  2.1436E−03 
                 1.3288E−03 
               
               
                 A10 = 
                 7.5238E−04 
                 3.2961E−03 
                  7.3704E−03 
                 2.5038E−03 
                 −2.8408E−03 
                 3.3682E−07 
               
               
                 A12 = 
                 — 
                 −3.7660E−04  
                 −8.6328E−04 
                 −2.8103E−04  
                  2.1414E−03 
                 7.5891E−05 
               
               
                 A14 = 
                 — 
                 — 
                 — 
                 — 
                 −6.4275E−04 
                 — 
               
               
                 A16 = 
                 — 
                 — 
                 — 
                 — 
                  6.9962E−05 
                 — 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Surface # 
                 15 
                 16 
                 17 
                 18 
               
               
                   
                   
               
               
                   
                 k = 
                 0.0000E+00 
                 −9.0000E+01 
                  6.8300E−01 
                 0.0000E+00 
               
               
                   
                 A4 = 
                 1.0791E−01 
                  9.3824E−02 
                 −2.0244E−02 
                 −2.1672E−02  
               
               
                   
                 A6 = 
                 −3.5285E−02  
                 −2.2837E−02 
                  1.3649E−03 
                 5.5218E−04 
               
               
                   
                 A8 = 
                 1.7403E−02 
                  1.2206E−02 
                 −7.8241E−04 
                 9.7425E−04 
               
               
                   
                 A10 = 
                 −7.1486E−03  
                 −5.4580E−03 
                  7.7924E−04 
                 −3.0023E−04  
               
               
                   
                 A12 = 
                 1.1386E−03 
                  1.3987E−03 
                 −2.9297E−04 
                 5.1522E−05 
               
               
                   
                 A14 = 
                 — 
                 −6.4657E−04 
                  5.2109E−05 
                 −5.1065E−06  
               
               
                   
                 A16 = 
                 — 
                  1.6443E−04 
                 −3.9488E−06 
                 — 
               
               
                   
                   
               
            
           
         
       
     
     In Table 3, k represents the conic coefficient of the equation of the aspheric surface profiles. A4-A16 represent the aspheric coefficients ranging from the 4th order to the 16th order. The tables presented below for each embodiment are the corresponding schematic parameter and aberration curves, and the definitions of the tables are the same as Table 1 to Table 3 of the 1st embodiment. Therefore, an explanation in this regard will not be provided again. 
     2nd Embodiment 
       FIG.  5    is a schematic view of an image capturing unit at the short-focal-length end according to the 2nd embodiment of the present disclosure.  FIG.  6    is a schematic view of the image capturing unit at the long-focal-length end according to the 2nd embodiment of the present disclosure.  FIG.  7    shows, in order from left to right, spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at the short-focal-length end according to the 2nd embodiment.  FIG.  8    shows, in order from left to right, spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at long-focal-length end according to the 2nd embodiment. In  FIG.  5    and  FIG.  6   , the image capturing unit includes the image capturing lens system (its reference numeral is omitted) of the present disclosure and an image sensor  299 . The image capturing lens system includes, in order from an object side to an image side along an optical path, a stop  201 , a first lens element  210 , a second lens element  220 , a third lens element  230 , an aperture stop  200 , a fourth lens element  240 , a fifth lens element  250 , a sixth lens element  260 , a seventh lens element  270 , an eighth lens element  280 , a filter  290  and an image surface  295 . In addition, the image capturing lens system has a configuration of a first lens group G1 (including the first lens element  210  and the second lens element  220 ), a second lens group G2 (including the third lens element  230 , the aperture stop  200 , the fourth lens element  240  and the fifth lens element  250 ), a third lens group G3 (including the sixth lens element  260  and the seventh lens element  270 ) and a fourth lens group G4 (including the eighth lens element  280 ). The first lens group G1 has negative refractive power, the second lens group G2 has positive refractive power, the third lens group G3 has negative refractive power, and the fourth lens group G4 has positive refractive power. The image capturing lens system includes eight lens elements ( 210 ,  220 ,  230 ,  240 ,  250 ,  260 ,  270  and  280 ) with no additional lens element disposed between each of the adjacent eight lens elements. 
     The focal length of the image capturing lens system is varied by changing axial distances between the four lens groups (G1, G2, G3 and G4) in a zooming process. As shown in  FIG.  5    and  FIG.  6   , the second lens group G2 is moved relative to the first lens group G1 along an optical axis in the zooming process, and the third lens group G3 is moved relative to the first lens group G1 along the optical axis in the zooming process. Furthermore, the image capturing lens system has a short-focal-length end as shown in  FIG.  5    and a long-focal-length end as shown in  FIG.  6   . In addition, when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end, the second lens group G2 is moved along the optical axis toward the object side relative to the first lens group G1. It is noted that there is no relative motion between lens elements of each of the four lens groups in the zooming process. 
     The first lens element  210  with positive refractive power has an object-side surface  211  being convex in a paraxial region thereof and an image-side surface  212  being concave in a paraxial region thereof. The first lens element  210  is made of plastic material and has the object-side surface  211  and the image-side surface  212  being both aspheric. 
     The second lens element  220  with negative refractive power has an object-side surface  221  being concave in a paraxial region thereof and an image-side surface  222  being concave in a paraxial region thereof. The second lens element  220  is made of plastic material and has the object-side surface  221  and the image-side surface  222  being both aspheric. 
     The third lens element  230  with positive refractive power has an object-side surface  231  being convex in a paraxial region thereof and an image-side surface  232  being convex in a paraxial region thereof. The third lens element  230  is made of plastic material and has the object-side surface  231  and the image-side surface  232  being both aspheric. The third lens element  230  has at least one inflection point in an off-axis region thereof. 
     The fourth lens element  240  with negative refractive power has an object-side surface  241  being concave in a paraxial region thereof and an image-side surface  242  being concave in a paraxial region thereof. The fourth lens element  240  is made of plastic material and has the object-side surface  241  and the image-side surface  242  being both aspheric. The fourth lens element  240  has at least one inflection point in an off-axis region thereof. 
     The fifth lens element  250  with positive refractive power has an object-side surface  251  being convex in a paraxial region thereof and an image-side surface  252  being convex in a paraxial region thereof. The fifth lens element  250  is made of glass material and has the object-side surface  251  and the image-side surface  252  being both spherical. 
     The sixth lens element  260  with positive refractive power has an object-side surface  261  being concave in a paraxial region thereof and an image-side surface  262  being convex in a paraxial region thereof. The sixth lens element  260  is made of plastic material and has the object-side surface  261  and the image-side surface  262  being both aspheric. The sixth lens element  260  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The seventh lens element  270  with negative refractive power has an object-side surface  271  being convex in a paraxial region thereof and an image-side surface  272  being concave in a paraxial region thereof. The seventh lens element  270  is made of plastic material and has the object-side surface  271  and the image-side surface  272  being both aspheric. The seventh lens element  270  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The eighth lens element  280  with positive refractive power has an object-side surface  281  being concave in a paraxial region thereof and an image-side surface  282  being convex in a paraxial region thereof. The eighth lens element  280  is made of plastic material and has the object-side surface  281  and the image-side surface  282  being both aspheric. The eighth lens element  280  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The filter  290  is made of glass material and located between the eighth lens element  280  and the image surface  295 , and will not affect the focal length of the image capturing lens system. The image sensor  299  is disposed on or near the image surface  295 . 
     In this embodiment, two of various focusing states of the image capturing lens system according to different focusing conditions are provided (i.e., different object distances). A first focusing state of the image capturing lens system is a state where the image capturing lens system focuses on an imaged object located at infinity, and a second focusing state of the image capturing lens system is a state where the image capturing lens system focuses on an imaged object located at a finite distance. 
     The detailed optical data of the 2nd embodiment are shown in Table 4 and Table 5, and the aspheric surface data are shown in Table 6 below. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 2nd Embodiment 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Focal Length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 D0  
                   
               
               
                 1 
                 Stop 
                 Plano 
                 −0.540  
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 2 
                 Lens 1 
                 6.011 
                 (ASP) 
                 1.500 
                 Plastic 
                 1.660 
                 20.4 
                 10.18 
               
               
                 3 
                   
                 51.572 
                 (ASP) 
                 0.571 
               
               
                 4 
                 Lens 2 
                 −128.493 
                 (ASP) 
                 0.446 
                 Plastic 
                 1.566 
                 37.4 
                 −4.03 
               
               
                 5 
                   
                 2.325 
                 (ASP) 
                 D5  
               
               
                 6 
                 Lens 3 
                 3.487 
                 (ASP) 
                 1.050 
                 Plastic 
                 1.544 
                 56.0 
                 4.03 
               
               
                 7 
                   
                 −5.273 
                 (ASP) 
                 −0.130  
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 Ape. Stop 
                 Plano 
                 0.295 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 9 
                 Lens 4 
                 −3.775 
                 (ASP) 
                 0.415 
                 Plastic 
                 1.639 
                 23.5 
                 −5.69 
               
               
                 10 
                   
                 100.000 
                 (ASP) 
                 0.200 
               
               
                 11 
                 Lens 5 
                 24.321 
                 (SPH) 
                 0.900 
                 Glass 
                 1.569 
                 56.1 
                 7.73 
               
               
                 12 
                   
                 −5.294 
                 (SPH) 
                 D12 
               
               
                 13 
                 Lens 6 
                 −7.323 
                 (ASP) 
                 0.453 
                 Plastic 
                 1.669 
                 19.5 
                 21.47 
               
               
                 14 
                   
                 −4.971 
                 (ASP) 
                 0.132 
               
               
                 15 
                 Lens 7 
                 10.698 
                 (ASP) 
                 0.323 
                 Plastic 
                 1.544 
                 56.0 
                 −7.11 
               
               
                 16 
                   
                 2.812 
                 (ASP) 
                 D16 
               
               
                 17 
                 Lens 8 
                 −21.670 
                 (ASP) 
                 0.626 
                 Plastic 
                 1.669 
                 19.5 
                 16.02 
               
               
                 18 
                   
                 −7.253 
                 (ASP) 
                 0.500 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 19 
                 Filter 
                 Plano 
                 0.210 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 20 
                   
                 Plano 
                 2.035 
               
               
                 21 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm (d-line). 
               
               
                 An effective radius of the stop 201 (Surface 1) is 2.155 mm. 
               
            
           
         
       
     
     The definitions of these parameters shown in Table 5 are the same as those stated in the 1st embodiment with corresponding values for the 2nd embodiment, so an explanation in this regard will not be provided again. 
     Moreover, these parameters can be calculated from Table 4 and Table 6 as the following values and satisfy the following conditions: 
     
       
         
           
               
             
               
                 TABLE 5 
               
               
                   
               
               
                 2nd Embodiment 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Short-focal-length End 
                 Long-focal-length End 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 First Focusing State 
                   
               
            
           
           
               
               
               
               
            
               
                   
                 f [mm] 
                 8.50 
                 17.01 
               
               
                   
                 Fno 
                 3.20 
                 4.59 
               
               
                   
                 HFOV [deg.] 
                 13.7 
                 6.7 
               
               
                   
                 D0 [mm] 
                 ∞ 
                 ∞ 
               
               
                   
                 D5 [mm] 
                 4.017 
                 0.419 
               
               
                   
                 D12 [mm] 
                 2.71 
                 5.477 
               
               
                   
                 D16 [mm] 
                 2.533 
                 3.365 
               
            
           
           
               
               
               
            
               
                   
                 Second Focusing State 
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Fno 
                 3.21 
                 4.59 
               
               
                   
                 HFOV [deg.] 
                 13.7 
                 6.7 
               
               
                   
                 D0 [mm] 
                 650.000 
                 650.000 
               
               
                   
                 D5 [mm] 
                 4.017 
                 0.419 
               
               
                   
                 D12 [mm] 
                 2.805 
                 5.822 
               
               
                   
                 D16 [mm] 
                 2.438 
                 3.019 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 (Vi/Ni)min 
                 11.65 
                 fG3/fG4 
                 −0.66 
               
               
                   
                 V1 + V6 + V8 
                 59.3 
                 fL/fS 
                 2.00 
               
               
                   
                 TDL/fL 
                 0.94 
                 fS/EPDS 
                 3.20 
               
               
                   
                 |BLL/BLS − 1| 
                 0.00E+00 
                 fS/fG1 
                 −0.89 
               
               
                   
                 |dTG34|/(TG3 + TG4) 
                 0.54 
                 fS/fG2 
                 1.67 
               
               
                   
                 |TDL/TDS − 1| 
                 6.23E−05 
                 fS/fG3 
                 −0.81 
               
               
                   
                 dTG12/dTG23 
                 −1.30 
                 fS/fG4 
                 0.53 
               
               
                   
                 dTG12/TG2 
                 −1.32 
                 HFOVL [deg.] 
                 6.7 
               
               
                   
                 TG1/TG2 
                 0.92 
                 HFOVS [deg.] 
                 13.7 
               
               
                   
                 TG2/TG3 
                 3.01 
                 Y11L/ImgHL 
                 1.06 
               
               
                   
                 TG3/TG4 
                 1.45 
                 Y11L/Y82L 
                 1.06 
               
               
                   
                 f1/f3 
                 2.53 
                 Y11S/ImgHS 
                 1.06 
               
               
                   
                 f4/f5 
                 −0.74 
                 Y11S/Y82S 
                 1.08 
               
               
                   
                 fG1/fG2 
                 −1.88 
                 — 
                 — 
               
               
                   
                   
               
            
           
         
       
     
     In the 2nd embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment, so an explanation in this regard will not be provided again. 
     
       
         
           
               
             
               
                 TABLE 6 
               
               
                   
               
               
                 Aspheric Coefficients 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Surface # 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
               
               
                   
               
               
                 k = 
                 2.3628E+00 
                 1.0000E+01 
                 −9.0000E+01 
                 −6.9993E+00 
                 −1.4952E+01 
                 0.0000E+00 
               
               
                 A4 = 
                 4.3050E−03 
                 2.0326E−02 
                 −3.8362E−02 
                 −7.1512E−03 
                  4.2193E−02 
                 1.5259E−02 
               
               
                 A6 = 
                 −4.9796E−04  
                 −8.3886E−03  
                 −2.2768E−03 
                 −1.1586E−02 
                 −2.0262E−02 
                 9.7553E−04 
               
               
                 A8 = 
                 1.2985E−04 
                 3.7290E−03 
                  1.0468E−02 
                  1.3952E−02 
                  9.1500E−03 
                 −2.1317E−03  
               
               
                 A10 = 
                 1.0610E−05 
                 −7.8894E−04  
                 −5.3907E−03 
                 −6.8411E−03 
                 −3.1932E−03 
                 2.6338E−04 
               
               
                 A12 = 
                 −5.6807E−06  
                 5.6206E−05 
                  1.2324E−03 
                  1.6316E−03 
                  6.2960E−04 
                 2.7273E−05 
               
               
                 A14 = 
                 6.5353E−07 
                 4.7824E−06 
                 −1.0924E−04 
                 −1.5480E−04 
                 −6.1562E−05 
                 −9.8413E−06  
               
               
                   
               
               
                 Surface # 
                 9 
                 10 
                 13 
                 14 
                 15 
                 16 
               
               
                   
               
               
                 k = 
                 0.0000E+00 
                 0.0000E+00 
                 −7.4029E+01  
                 0.0000E+00 
                  0.0000E+00 
                 −1.2717E+01 
               
               
                 A4 = 
                 4.7011E−02 
                 3.5676E−02 
                 6.0107E−03 
                 1.0029E−02 
                 −1.4465E−01 
                 −6.6613E−02 
               
               
                 A6 = 
                 −9.2826E−03  
                 −8.4418E−03  
                 3.6254E−03 
                 8.2184E−03 
                  9.6340E−02 
                  5.0861E−02 
               
               
                 A8 = 
                 7.9814E−04 
                 1.9214E−03 
                 2.0804E−03 
                 3.1008E−03 
                 −3.8421E−02 
                 −2.3130E−02 
               
               
                 A10 = 
                 6.8684E−05 
                 −1.8055E−04  
                 −1.5719E−03  
                 −3.8155E−03  
                  7.2091E−03 
                  5.6557E−03 
               
               
                 A12 = 
                 — 
                 2.5893E−07 
                 1.5092E−04 
                 7.7594E−04 
                 −3.3564E−04 
                 −3.8650E−04 
               
               
                 A14 = 
                 — 
                 — 
                 6.5861E−05 
                 — 
                 — 
                 −6.7100E−05 
               
               
                 A16 = 
                 — 
                 — 
                 −1.2478E−05  
                 — 
                 — 
                  8.4265E−06 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Surface # 
                 17 
                 18 
               
               
                   
                   
               
               
                   
                 k = 
                 −1.6429E+01 
                 0.0000E+00 
               
               
                   
                 A4 = 
                  7.9378E−03 
                 9.0643E−03 
               
               
                   
                 A6 = 
                  1.0603E−03 
                 2.1835E−04 
               
               
                   
                 A8 = 
                 −1.1309E−03 
                 −2.7320E−04  
               
               
                   
                 A10 = 
                  4.0079E−04 
                 −2.9050E−05  
               
               
                   
                 A12 = 
                 −9.9519E−05 
                 1.6309E−05 
               
               
                   
                 A14 = 
                  1.4819E−05 
                 −1.8383E−06  
               
               
                   
                 A16 = 
                 −1.0232E−06 
                 — 
               
               
                   
                   
               
            
           
         
       
     
     3rd Embodiment 
       FIG.  9    is a schematic view of an image capturing unit at the short-focal-length end according to the 3rd embodiment of the present disclosure.  FIG.  10    is a schematic view of the image capturing unit at the long-focal-length end according to the 3rd embodiment of the present disclosure.  FIG.  11    shows, in order from left to right, spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at the short-focal-length end according to the 3rd embodiment.  FIG.  12    shows, in order from left to right, spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at long-focal-length end according to the 3rd embodiment. In  FIG.  9    and  FIG.  10   , the image capturing unit includes the image capturing lens system (its reference numeral is omitted) of the present disclosure and an image sensor  399 . The image capturing lens system includes, in order from an object side to an image side along an optical path, a stop  301 , a first lens element  310 , a second lens element  320 , a third lens element  330 , an aperture stop  300 , a fourth lens element  340 , a fifth lens element  350 , a sixth lens element  360 , a seventh lens element  370 , an eighth lens element  380 , a filter  390  and an image surface  395 . In addition, the image capturing lens system has a configuration of a first lens group G1 (including the first lens element  310  and the second lens element  320 ), a second lens group G2 (including the third lens element  330 , the aperture stop  300 , the fourth lens element  340  and the fifth lens element  350 ), a third lens group G3 (including the sixth lens element  360  and the seventh lens element  370 ) and a fourth lens group G4 (including the eighth lens element  380 ). The first lens group G1 has negative refractive power, the second lens group G2 has positive refractive power, the third lens group G3 has negative refractive power, and the fourth lens group G4 has positive refractive power. The image capturing lens system includes eight lens elements ( 310 ,  320 ,  330 ,  340 ,  350 ,  360 ,  370  and  380 ) with no additional lens element disposed between each of the adjacent eight lens elements. 
     The focal length of the image capturing lens system is varied by changing axial distances between the four lens groups (G1, G2, G3 and G4) in a zooming process. As shown in  FIG.  9    and  FIG.  10   , the second lens group G2 is moved relative to the first lens group G1 along an optical axis in the zooming process, and the third lens group G3 is moved relative to the first lens group G1 along the optical axis in the zooming process. Furthermore, the image capturing lens system has a short-focal-length end as shown in  FIG.  9    and a long-focal-length end as shown in  FIG.  10   . In addition, when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end, the second lens group G2 is moved along the optical axis toward the object side relative to the first lens group G1. It is noted that there is no relative motion between lens elements of each of the four lens groups in the zooming process. 
     The first lens element  310  with positive refractive power has an object-side surface  311  being convex in a paraxial region thereof and an image-side surface  312  being convex in a paraxial region thereof. The first lens element  310  is made of plastic material and has the object-side surface  311  and the image-side surface  312  being both aspheric. 
     The second lens element  320  with negative refractive power has an object-side surface  321  being concave in a paraxial region thereof and an image-side surface  322  being concave in a paraxial region thereof. The second lens element  320  is made of plastic material and has the object-side surface  321  and the image-side surface  322  being both aspheric. 
     The third lens element  330  with positive refractive power has an object-side surface  331  being convex in a paraxial region thereof and an image-side surface  332  being convex in a paraxial region thereof. The third lens element  330  is made of plastic material and has the object-side surface  331  and the image-side surface  332  being both aspheric. The third lens element  330  has at least one inflection point in an off-axis region thereof. 
     The fourth lens element  340  with negative refractive power has an object-side surface  341  being concave in a paraxial region thereof and an image-side surface  342  being concave in a paraxial region thereof. The fourth lens element  340  is made of plastic material and has the object-side surface  341  and the image-side surface  342  being both aspheric. The fourth lens element  340  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The fifth lens element  350  with positive refractive power has an object-side surface  351  being convex in a paraxial region thereof and an image-side surface  352  being convex in a paraxial region thereof. The fifth lens element  350  is made of glass material and has the object-side surface  351  and the image-side surface  352  being both spherical. 
     The sixth lens element  360  with negative refractive power has an object-side surface  361  being concave in a paraxial region thereof and an image-side surface  362  being convex in a paraxial region thereof. The sixth lens element  360  is made of plastic material and has the object-side surface  361  and the image-side surface  362  being both aspheric. The sixth lens element  360  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The seventh lens element  370  with negative refractive power has an object-side surface  371  being concave in a paraxial region thereof and an image-side surface  372  being convex in a paraxial region thereof. The seventh lens element  370  is made of plastic material and has the object-side surface  371  and the image-side surface  372  being both aspheric. The seventh lens element  370  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The eighth lens element  380  with positive refractive power has an object-side surface  381  being convex in a paraxial region thereof and an image-side surface  382  being convex in a paraxial region thereof. The eighth lens element  380  is made of plastic material and has the object-side surface  381  and the image-side surface  382  being both aspheric. The eighth lens element  380  has at least one inflection point in an off-axis region thereof. 
     The filter  390  is made of glass material and located between the eighth lens element  380  and the image surface  395 , and will not affect the focal length of the image capturing lens system. The image sensor  399  is disposed on or near the image surface  395 . 
     In this embodiment, two of various focusing states of the image capturing lens system according to different focusing conditions are provided. A first focusing state of the image capturing lens system is a state where the image capturing lens system focuses on an imaged object located at infinity, and a second focusing state of the image capturing lens system is a state where the image capturing lens system focuses on an imaged object located at a finite distance. 
     The detailed optical data of the 3rd embodiment are shown in Table 7 and Table 8, and the aspheric surface data are shown in Table 9 below. 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 3rd Embodiment 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Focal Length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 D0  
                   
               
               
                 1 
                 Stop 
                 Plano 
                 −0.524  
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 2 
                 Lens 1 
                 6.663 
                 (ASP) 
                 1.500 
                 Plastic 
                 1.660 
                 20.4 
                 6.43 
               
               
                 3 
                   
                 −10.629 
                 (ASP) 
                 0.492 
               
               
                 4 
                 Lens 2 
                 −13.687 
                 (ASP) 
                 0.548 
                 Plastic 
                 1.587 
                 28.3 
                 −3.06 
               
               
                 5 
                   
                 2.100 
                 (ASP) 
                 D5  
               
               
                 6 
                 Lens 3 
                 3.245 
                 (ASP) 
                 1.050 
                 Plastic 
                 1.544 
                 56.0 
                 4.00 
               
               
                 7 
                   
                 −5.840 
                 (ASP) 
                 −0.130  
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 Ape. Stop 
                 Plano 
                 0.193 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 9 
                 Lens 4 
                 −7.086 
                 (ASP) 
                 0.571 
                 Plastic 
                 1.639 
                 23.5 
                 −6.26 
               
               
                 10 
                   
                 9.458 
                 (ASP) 
                 0.172 
               
               
                 11 
                 Lens 5 
                 7.976 
                 (SPH) 
                 0.868 
                 Glass 
                 1.804 
                 46.6 
                 9.56 
               
               
                 12 
                   
                 −200.000 
                 (SPH) 
                 D12 
               
               
                 13 
                 Lens 6 
                 −9.026 
                 (ASP) 
                 0.320 
                 Plastic 
                 1.669 
                 19.5 
                 −124.26 
               
               
                 14 
                   
                 −10.269 
                 (ASP) 
                 0.171 
               
               
                 15 
                 Lens 7 
                 −4.372 
                 (ASP) 
                 0.320 
                 Plastic 
                 1.544 
                 56.0 
                 −9.96 
               
               
                 16 
                   
                 −23.212 
                 (ASP) 
                 D16 
               
               
                 17 
                 Lens 8 
                 16.970 
                 (ASP) 
                 0.800 
                 Plastic 
                 1.669 
                 19.5 
                 10.34 
               
               
                 18 
                   
                 −11.465 
                 (ASP) 
                 0.500 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 19 
                 Filter 
                 Plano 
                 0.210 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 20 
                   
                 Plano 
                 2.675 
               
               
                 21 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm (d-line). 
               
               
                 An effective radius of the stop 301 (Surface 1) is 2.200 mm. 
               
            
           
         
       
     
     As shown in Table 8 below, in each focusing state, three different zooming states between the short-focal-length end and the long-focal-length end of the image capturing lens system and corresponding optical data are also disclosed in this embodiment. The definitions of these parameters shown in Table 8 are the same as those stated in the 1st embodiment with corresponding values for the 3rd embodiment, so an explanation in this regard will not be provided again. 
     Moreover, these parameters can be calculated from Table 7 and Table 9 as the following values and satisfy the following conditions: 
     
       
         
           
               
             
               
                 TABLE 8 
               
               
                   
               
               
                 3rd Embodiment 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Short-focal- 
                   
                   
                   
                 Long-focal- 
               
               
                   
                 length End 
                   
                   
                   
                 length End 
               
               
                   
                   
               
            
           
           
               
               
            
               
                   
                 First Focusing State 
               
            
           
           
               
               
               
               
               
               
            
               
                 f [mm] 
                 8.50 
                 11.05 
                 12.75 
                 14.44 
                 17.00 
               
               
                 Fno 
                 3.20 
                 3.70 
                 3.99 
                 4.26 
                 4.61 
               
               
                 HFOV [deg.] 
                 13.7 
                 10.4 
                 9.0 
                 7.9 
                 6.7 
               
               
                 D0 [mm] 
                 ∞ 
                 ∞ 
                 ∞ 
                 ∞ 
                 ∞ 
               
               
                 D5 [mm] 
                 4.144 
                 2.729 
                 1.997 
                 1.381 
                 0.588 
               
               
                 D12 [mm] 
                 2.536 
                 3.192 
                 3.785 
                 4.496 
                 5.872 
               
               
                 D16 [mm] 
                 2.047 
                 2.806 
                 2.945 
                 2.850 
                 2.267 
               
            
           
           
               
               
            
               
                   
                 Second Focusing State 
               
            
           
           
               
               
               
               
               
               
            
               
                 Fno 
                 3.21 
                 3.71 
                 4.00 
                 4.27 
                 4.62 
               
               
                 HFOV [deg.] 
                 13.6 
                 10.4 
                 9.0 
                 7.9 
                 6.7 
               
               
                 D0 [mm] 
                 800.000 
                 800.000 
                 800.000 
                 800.000 
                 800.000 
               
               
                 D5 [mm] 
                 4.144 
                 2.729 
                 1.997 
                 1.381 
                 0.588 
               
               
                 D12 [mm] 
                 2.608 
                 3.302 
                 3.928 
                 4.683 
                 6.162 
               
               
                 D16 [mm] 
                 1.975 
                 2.696 
                 2.802 
                 2.663 
                 1.977 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 (Vi/Ni)min 
                 11.65 
                 fG3/fG4 
                 −0.88 
               
               
                   
                 V1 + V6 + V8 
                 59.3 
                 fL/fS 
                 2.00 
               
               
                   
                 TDL/fL 
                 0.92 
                 fS/EPDS 
                 3.20 
               
               
                   
                 |BLL/BLS − 1| 
                 0.00E+00 
                 fS/fG1 
                 −0.87 
               
               
                   
                 |dTG34|/(TG3 + TG4) 
                 0.14 
                 fS/fG2 
                 1.70 
               
               
                   
                 |TDL/TDS − 1| 
                 0.00E+00 
                 fS/fG3 
                 −0.94 
               
               
                   
                 dTG12/dTG23 
                 −1.07 
                 fS/fG4 
                 0.82 
               
               
                   
                 dTG12/TG2 
                 −1.31 
                 HFOVL [deg.] 
                 6.7 
               
               
                   
                 TG1/TG2 
                 0.93 
                 HFOVS [deg.] 
                 13.7 
               
               
                   
                 TG2/TG3 
                 3.36 
                 Y11L/ImgHL 
                 1.08 
               
               
                   
                 TG3/TG4 
                 1.01 
                 Y11L/Y82L 
                 1.03 
               
               
                   
                 f1/f3 
                 1.61 
                 Y11S/ImgHS 
                 1.08 
               
               
                   
                 f4/f5 
                 −0.65 
                 Y11S/Y82S 
                 1.04 
               
               
                   
                 fG1/fG2 
                 −1.96 
                 — 
                 — 
               
               
                   
                   
               
            
           
         
       
     
     In the 3rd embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment, so an explanation in this regard will not be provided again. 
     
       
         
           
               
             
               
                 TABLE 9 
               
               
                   
               
               
                 Aspheric Coefficients 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Surface # 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
               
               
                   
               
               
                 k = 
                 2.1935E+00 
                 −2.0612E+01  
                  1.7056E+01 
                 −5.4098E+00 
                 −1.1537E+01 
                 0.0000E+00 
               
               
                 A4 = 
                 4.4154E−03 
                 2.0388E−02 
                 −3.0966E−02 
                 −8.9774E−03 
                  3.8911E−02 
                 2.7193E−02 
               
               
                 A6 = 
                 −3.8619E−04  
                 −1.0507E−02  
                 −4.5733E−03 
                 −5.9679E−03 
                 −1.7419E−02 
                 −2.2117E−02  
               
               
                 A8 = 
                 3.7519E−05 
                 4.4353E−03 
                  1.0856E−02 
                  1.0058E−02 
                  7.5638E−03 
                 1.1673E−02 
               
               
                 A10 = 
                 6.4082E−05 
                 −9.6337E−04  
                 −5.3912E−03 
                 −5.4907E−03 
                 −2.8366E−03 
                 −3.5164E−03  
               
               
                 A12 = 
                 −1.7463E−05  
                 7.9005E−05 
                  1.2284E−03 
                  1.4205E−03 
                  6.8549E−04 
                 4.7226E−04 
               
               
                 A14 = 
                 1.7042E−06 
                 3.0152E−06 
                 −1.0865E−04 
                 −1.4464E−04 
                 −8.3490E−05 
                 −2.6450E−05  
               
               
                   
               
               
                 Surface # 
                 9 
                 10 
                 13 
                 14 
                 15 
                 16 
               
               
                   
               
               
                 k = 
                 0.0000E+00 
                 0.0000E+00 
                 1.7955E+01 
                  0.0000E+00 
                 0.0000E+00 
                 −4.1464E+01 
               
               
                 A4 = 
                 4.6220E−02 
                 2.7976E−02 
                 −2.3108E−02  
                 −1.2458E−02 
                 1.0722E−01 
                  8.6139E−02 
               
               
                 A6 = 
                 −2.6525E−02  
                 −6.5608E−03  
                 7.2911E−03 
                 −1.2726E−02 
                 −9.0478E−02  
                 −5.6130E−02 
               
               
                 A8 = 
                 1.3811E−02 
                 3.5088E−03 
                 1.0106E−02 
                  1.8896E−02 
                 4.0764E−02 
                  1.7426E−02 
               
               
                 A10 = 
                 −3.9519E−03  
                 −1.0811E−03  
                 −5.9084E−03  
                 −6.4197E−03 
                 −9.7072E−03  
                 −1.8728E−03 
               
               
                 A12 = 
                 4.3620E−04 
                 1.2800E−04 
                 1.4204E−03 
                  7.4963E−04 
                 9.4400E−04 
                 −3.9848E−04 
               
               
                 A14 = 
                 — 
                 — 
                 −1.7231E−04  
                 — 
                 — 
                  1.2278E−04 
               
               
                 A16 = 
                 — 
                 — 
                 1.1451E−05 
                 — 
                 — 
                 −7.8019E−06 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Surface # 
                 17 
                 18 
               
               
                   
                   
               
               
                   
                 k = 
                 −2.1318E+01 
                 0.0000E+00 
               
               
                   
                 A4 = 
                  5.2440E−03 
                 4.4501E−03 
               
               
                   
                 A6 = 
                 −1.4389E−03 
                 −1.2751E−03  
               
               
                   
                 A8 = 
                  8.7371E−05 
                 1.0078E−04 
               
               
                   
                 A10 = 
                  2.5108E−05 
                 −8.7330E−06  
               
               
                   
                 A12 = 
                 −1.2739E−05 
                 7.7728E−09 
               
               
                   
                 A14 = 
                  1.9520E−06 
                 −1.3898E−07  
               
               
                   
                 A16 = 
                 −1.4324E−07 
                 — 
               
               
                   
                   
               
            
           
         
       
     
     4th Embodiment 
       FIG.  13    is a schematic view of an image capturing unit at the short-focal-length end according to the 4th embodiment of the present disclosure.  FIG.  14    is a schematic view of the image capturing unit at the long-focal-length end according to the 4th embodiment of the present disclosure.  FIG.  15    shows, in order from left to right, spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at the short-focal-length end according to the 4th embodiment.  FIG.  16    shows, in order from left to right, spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at long-focal-length end according to the 4th embodiment. In  FIG.  13    and  FIG.  14   , the image capturing unit includes the image capturing lens system (its reference numeral is omitted) of the present disclosure and an image sensor  499 . The image capturing lens system includes, in order from an object side to an image side along an optical path, a stop  401 , a first lens element  410 , a second lens element  420 , a third lens element  430 , an aperture stop  400 , a fourth lens element  440 , a fifth lens element  450 , a sixth lens element  460 , a seventh lens element  470 , an eighth lens element  480 , a filter  490  and an image surface  495 . In addition, the image capturing lens system has a configuration of a first lens group G1 (including the first lens element  410  and the second lens element  420 ), a second lens group G2 (including the third lens element  430 , the aperture stop  400 , the fourth lens element  440  and the fifth lens element  450 ), a third lens group G3 (including the sixth lens element  460  and the seventh lens element  470 ) and a fourth lens group G4 (including the eighth lens element  480 ). The first lens group G1 has negative refractive power, the second lens group G2 has positive refractive power, the third lens group G3 has negative refractive power, and the fourth lens group G4 has positive refractive power. The image capturing lens system includes eight lens elements ( 410 ,  420 ,  430 ,  440 ,  450 ,  460 ,  470  and  480 ) with no additional lens element disposed between each of the adjacent eight lens elements. 
     The focal length of the image capturing lens system is varied by changing axial distances between the four lens groups (G1, G2, G3 and G4) in a zooming process. As shown in  FIG.  13    and  FIG.  14   , the second lens group G2 is moved relative to the first lens group G1 along an optical axis in the zooming process, and the third lens group G3 is moved relative to the first lens group G1 along the optical axis in the zooming process. Furthermore, the image capturing lens system has a short-focal-length end as shown in  FIG.  13    and a long-focal-length end as shown in  FIG.  14   . In addition, when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end, the second lens group G2 is moved along the optical axis toward the object side relative to the first lens group G1. It is noted that there is no relative motion between lens elements of each of the four lens groups in the zooming process. 
     The first lens element  410  with positive refractive power has an object-side surface  411  being convex in a paraxial region thereof and an image-side surface  412  being convex in a paraxial region thereof. The first lens element  410  is made of plastic material and has the object-side surface  411  and the image-side surface  412  being both aspheric. 
     The second lens element  420  with negative refractive power has an object-side surface  421  being concave in a paraxial region thereof and an image-side surface  422  being concave in a paraxial region thereof. The second lens element  420  is made of plastic material and has the object-side surface  421  and the image-side surface  422  being both aspheric. 
     The third lens element  430  with positive refractive power has an object-side surface  431  being convex in a paraxial region thereof and an image-side surface  432  being convex in a paraxial region thereof. The third lens element  430  is made of plastic material and has the object-side surface  431  and the image-side surface  432  being both aspheric. The third lens element  430  has at least one inflection point in an off-axis region thereof. 
     The fourth lens element  440  with negative refractive power has an object-side surface  441  being concave in a paraxial region thereof and an image-side surface  442  being concave in a paraxial region thereof. The fourth lens element  440  is made of plastic material and has the object-side surface  441  and the image-side surface  442  being both aspheric. The fourth lens element  440  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The fifth lens element  450  with positive refractive power has an object-side surface  451  being convex in a paraxial region thereof and an image-side surface  452  being convex in a paraxial region thereof. The fifth lens element  450  is made of plastic material and has the object-side surface  451  and the image-side surface  452  being both aspheric. The fifth lens element  450  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The sixth lens element  460  with positive refractive power has an object-side surface  461  being concave in a paraxial region thereof and an image-side surface  462  being convex in a paraxial region thereof. The sixth lens element  460  is made of plastic material and has the object-side surface  461  and the image-side surface  462  being both aspheric. The sixth lens element  460  has at least one inflection point in an off-axis region thereof. 
     The seventh lens element  470  with negative refractive power has an object-side surface  471  being concave in a paraxial region thereof and an image-side surface  472  being convex in a paraxial region thereof. The seventh lens element  470  is made of plastic material and has the object-side surface  471  and the image-side surface  472  being both aspheric. The seventh lens element  470  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The eighth lens element  480  with positive refractive power has an object-side surface  481  being convex in a paraxial region thereof and an image-side surface  482  being convex in a paraxial region thereof. The eighth lens element  480  is made of plastic material and has the object-side surface  481  and the image-side surface  482  being both aspheric. The eighth lens element  480  has at least one inflection point in an off-axis region thereof. 
     The filter  490  is made of glass material and located between the eighth lens element  480  and the image surface  495 , and will not affect the focal length of the image capturing lens system. The image sensor  499  is disposed on or near the image surface  495 . 
     In this embodiment, two of various focusing states of the image capturing lens system according to different focusing conditions are provided. A first focusing state of the image capturing lens system is a state where the image capturing lens system focuses on an imaged object located at infinity, and a second focusing state of the image capturing lens system is a state where the image capturing lens system focuses on an imaged object located at a finite distance. 
     The detailed optical data of the 4th embodiment are shown in Table 10 and Table 11, and the aspheric surface data are shown in Table 12 below. 
     
       
         
           
               
             
               
                 TABLE 10 
               
             
            
               
                   
               
               
                 4th Embodiment 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Focal Length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 D0  
                   
               
               
                 1 
                 Stop 
                 Plano 
                 −0.558  
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 2 
                 Lens 1 
                 6.038 
                 (ASP) 
                 1.500 
                 Plastic 
                 1.660 
                 20.4 
                 6.15 
               
               
                 3 
                   
                 −11.165 
                 (ASP) 
                 0.356 
               
               
                 4 
                 Lens 2 
                 −10.929 
                 (ASP) 
                 0.570 
                 Plastic 
                 1.587 
                 28.3 
                 −3.06 
               
               
                 5 
                   
                 2.191 
                 (ASP) 
                 D5  
               
               
                 6 
                 Lens 3 
                 3.049 
                 (ASP) 
                 0.830 
                 Plastic 
                 1.544 
                 56.0 
                 4.47 
               
               
                 7 
                   
                 −10.888 
                 (ASP) 
                 0.008 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 8 
                 Ape. Stop 
                 Plano 
                 0.022 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 9 
                 Lens 4 
                 −29.922 
                 (ASP) 
                 0.320 
                 Plastic 
                 1.639 
                 23.5 
                 −7.06 
               
               
                 10 
                   
                 5.331 
                 (ASP) 
                 0.137 
               
               
                 11 
                 Lens 5 
                 7.891 
                 (ASP) 
                 0.950 
                 Plastic 
                 1.544 
                 56.0 
                 9.27 
               
               
                 12 
                   
                 −13.378 
                 (ASP) 
                 D12 
               
               
                 13 
                 Lens 6 
                 −7.765 
                 (ASP) 
                 0.470 
                 Plastic 
                 1.669 
                 19.5 
                 28.67 
               
               
                 14 
                   
                 −5.661 
                 (ASP) 
                 0.200 
               
               
                 15 
                 Lens 7 
                 −2.755 
                 (ASP) 
                 0.354 
                 Plastic 
                 1.587 
                 28.3 
                 −6.74 
               
               
                 16 
                   
                 −9.509 
                 (ASP) 
                 D16 
               
               
                 17 
                 Lens 8 
                 15.278 
                 (ASP) 
                 0.800 
                 Plastic 
                 1.669 
                 19.5 
                 8.92 
               
               
                 18 
                   
                 −9.589 
                 (ASP) 
                 0.320 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 19 
                 Filter 
                 Plano 
                 0.210 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 20 
                   
                 Plano 
                 2.818 
               
               
                 21 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm (d-line). 
               
               
                 An effective radius of the stop 401 (Surface 1) is 2.200 mm. 
               
            
           
         
       
     
     As shown in Table 11 below, in each focusing state, three different zooming states between the short-focal-length end and the long-focal-length end of the image capturing lens system and corresponding optical data are also disclosed in this embodiment. The definitions of these parameters shown in Table 11 are the same as those stated in the 1st embodiment with corresponding values for the 4th embodiment, so an explanation in this regard will not be provided again. 
     Moreover, these parameters can be calculated from Table 10 and Table 12 as the following values and satisfy the following conditions: 
     
       
         
           
               
             
               
                 TABLE 11 
               
               
                   
               
               
                 4th Embodiment 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Short-focal- 
                   
                   
                   
                 Long-focal- 
               
               
                   
                 length End 
                   
                   
                   
                 length End 
               
               
                   
                   
               
            
           
           
               
               
            
               
                   
                 First Focusing State 
               
            
           
           
               
               
               
               
               
               
            
               
                 f [mm] 
                 8.50 
                 11.05 
                 12.75 
                 14.45 
                 17.00 
               
               
                 Fno 
                 3.24 
                 3.75 
                 4.05 
                 4.33 
                 4.69 
               
               
                 HFOV [deg.] 
                 13.7 
                 10.4 
                 9.0 
                 7.9 
                 6.8 
               
               
                 D0 [mm] 
                 ∞ 
                 ∞ 
                 ∞ 
                 ∞ 
                 ∞ 
               
               
                 D5 [mm] 
                 4.292 
                 2.828 
                 2.065 
                 1.416 
                 0.583 
               
               
                 D12 [mm] 
                 3.265 
                 3.957 
                 4.575 
                 5.316 
                 6.740 
               
               
                 D16 [mm] 
                 1.553 
                 2.324 
                 2.471 
                 2.378 
                 1.787 
               
            
           
           
               
               
            
               
                   
                 Second Focusing State 
               
            
           
           
               
               
               
               
               
               
            
               
                 Fno 
                 3.25 
                 3.76 
                 4.06 
                 4.34 
                 4.69 
               
               
                 HFOV [deg.] 
                 13.7 
                 10.4 
                 9.0 
                 7.9 
                 6.8 
               
               
                 D0 [mm] 
                 800.000 
                 800.000 
                 800.000 
                 800.000 
                 800.000 
               
               
                 D5 [mm] 
                 4.292 
                 2.828 
                 2.065 
                 1.416 
                 0.583 
               
               
                 D12 [mm] 
                 3.347 
                 4.079 
                 4.733 
                 5.524 
                 7.056 
               
               
                 D16 [mm] 
                 1.471 
                 2.203 
                 2.312 
                 2.171 
                 1.471 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 (Vi/Ni)min 
                 11.65 
                 fG3/fG4 
                 −0.96 
               
               
                   
                 V1 + V6 + V8 
                 59.3 
                 fL/fS 
                 2.00 
               
               
                   
                 TDL/fL 
                 0.92 
                 fS/EPDS 
                 3.24 
               
               
                   
                 |BLL/BLS − 1| 
                 0.00E+00 
                 fS/fG1 
                 −0.83 
               
               
                   
                 |dTG34|/(TG3 + TG4) 
                 0.13 
                 fS/fG2 
                 1.62 
               
               
                   
                 |TDL/TDS − 1| 
                 0.00E+00 
                 fS/fG3 
                 −0.99 
               
               
                   
                 dTG12/dTG23 
                 −1.07 
                 fS/fG4 
                 0.95 
               
               
                   
                 dTG12/TG2 
                 −1.64 
                 HFOVL [deg.] 
                 6.8 
               
               
                   
                 TG1/TG2 
                 1.07 
                 HFOVS [deg.] 
                 13.7 
               
               
                   
                 TG2/TG3 
                 2.21 
                 Y11L/lmgHL 
                 1.06 
               
               
                   
                 TG3/TG4 
                 1.28 
                 Y11L/Y82L 
                 1.00 
               
               
                   
                 f1/f3 
                 1.38 
                 Y11S/lmgHS 
                 1.08 
               
               
                   
                 f4/f5 
                 −0.76 
                 Y11S/Y82S 
                 1.04 
               
               
                   
                 fG1/fG2 
                 −1.95 
                 — 
                 — 
               
               
                   
                   
               
            
           
         
       
     
     In the 4th embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment, so an explanation in this regard will not be provided again. 
     
       
         
           
               
             
               
                 TABLE 12 
               
               
                   
               
               
                 Aspheric Coefficients 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Surface # 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
               
               
                   
               
               
                 k = 
                 7.8725E−01 
                 8.7599E+00 
                 2.8663E+01 
                 −6.7140E+00 
                 −1.3027E+01 
                 0.0000E+00 
               
               
                 A4 = 
                 3.2885E−03 
                 1.7147E−02 
                 −3.2989E−02  
                  5.6106E−04 
                  4.3692E−02 
                 −9.2015E−03  
               
               
                 A6 = 
                 −4.0734E−04  
                 −1.0704E−02  
                 4.7263E−04 
                 −6.6138E−03 
                 −2.4331E−02 
                 1.6921E−02 
               
               
                 A8 = 
                 4.9553E−05 
                 5.1108E−03 
                 1.0262E−02 
                  9.3225E−03 
                  1.0378E−02 
                 −4.2833E−03  
               
               
                 A10 = 
                 1.1379E−04 
                 −7.9195E−04  
                 −5.7494E−03  
                 −5.5512E−03 
                 −2.6001E−03 
                 7.7378E−04 
               
               
                 A12 = 
                 −3.3641E−05  
                 −9.6334E−05  
                 1.3352E−03 
                  1.5662E−03 
                  4.0337E−04 
                 −4.3163E−04  
               
               
                 A14 = 
                 3.4122E−06 
                 3.2229E−05 
                 −1.1281E−04  
                 −1.7186E−04 
                 −4.5958E−05 
                 6.6604E−05 
               
               
                   
               
               
                 Surface # 
                 9 
                 10 
                 11 
                 12 
                 13 
                 14 
               
               
                   
               
               
                 k = 
                 0.0000E+00 
                 0.0000E+00 
                  0.0000E+00 
                 0.0000E+00 
                 1.4141E+01 
                 0.0000E+00 
               
               
                 A4 = 
                 2.4982E−02 
                 1.1710E−02 
                 −1.7477E−02 
                 4.9016E−03 
                 1.6487E−02 
                 1.0667E−02 
               
               
                 A6 = 
                 7.4874E−03 
                 3.1586E−02 
                  4.3656E−02 
                 5.4514E−03 
                 −9.8428E−03  
                 −2.1758E−02  
               
               
                 A8 = 
                 −3.3254E−03  
                 −2.1853E−02  
                 −1.9996E−02 
                 −1.0043E−03  
                 4.8389E−03 
                 6.6673E−03 
               
               
                 A10 = 
                 −4.4972E−04  
                 6.1290E−03 
                  5.2342E−03 
                 6.4769E−04 
                 −2.9323E−03  
                 2.1829E−03 
               
               
                 A12 = 
                 1.4844E−04 
                 −7.9767E−04  
                 −7.2510E−04 
                 −9.9915E−05  
                 1.1323E−03 
                 −1.6875E−03  
               
               
                 A14 = 
                 — 
                 — 
                 — 
                 — 
                 −1.3316E−04  
                 2.9059E−04 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Surface # 
                 15 
                 16 
                 17 
                 18 
               
               
                   
                   
               
               
                   
                 k = 
                 0.0000E+00 
                 −5.7175E+00 
                 −1.5404E+01 
                 0.0000E+00 
               
               
                   
                 A4 = 
                 2.3759E−02 
                  1.6517E−02 
                  1.0135E−02 
                 1.1368E−02 
               
               
                   
                 A6 = 
                 −2.5781E−02  
                 −8.1244E−03 
                 −3.9061E−03 
                 −3.5771E−03  
               
               
                   
                 A8 = 
                 2.5322E−02 
                  1.3335E−02 
                  1.2967E−03 
                 1.0598E−03 
               
               
                   
                 A10 = 
                 −7.8571E−03  
                 −6.7096E−03 
                 −3.4694E−04 
                 −2.8558E−04  
               
               
                   
                 A12 = 
                 3.7176E−04 
                  1.3919E−03 
                  5.0720E−05 
                 4.1542E−05 
               
               
                   
                 A14 = 
                 1.2492E−04 
                 −1.0693E−04 
                 −3.1506E−06 
                 −2.5153E−06  
               
               
                   
                   
               
            
           
         
       
     
     5th Embodiment 
       FIG.  17    is a schematic view of an image capturing unit at the short-focal-length end according to the 5th embodiment of the present disclosure.  FIG.  18    is a schematic view of the image capturing unit at the long-focal-length end according to the 5th embodiment of the present disclosure.  FIG.  19    shows, in order from left to right, spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at the short-focal-length end according to the 5th embodiment.  FIG.  20    shows, in order from left to right, spherical aberration curves, astigmatic field curves and a distortion curve of the image capturing unit at long-focal-length end according to the 5th embodiment. In  FIG.  17    and  FIG.  18   , the image capturing unit includes the image capturing lens system (its reference numeral is omitted) of the present disclosure and an image sensor  599 . The image capturing lens system includes, in order from an object side to an image side along an optical path, a stop  501 , a first lens element  510 , a second lens element  520 , a third lens element  530 , a fourth lens element  540 , an aperture stop  500 , a fifth lens element  550 , a sixth lens element  560 , a seventh lens element  570 , an eighth lens element  580 , a filter  590  and an image surface  595 . In addition, the image capturing lens system has a configuration of a first lens group G1 (including the first lens element  510  and the second lens element  520 ), a second lens group G2 (including the third lens element  530 , the fourth lens element  540 , the aperture stop  500  and the fifth lens element  550 ), a third lens group G3 (including the sixth lens element  560  and the seventh lens element  570 ) and a fourth lens group G4 (including the eighth lens element  580 ). The first lens group G1 has positive refractive power, the second lens group G2 has negative refractive power, the third lens group G3 has positive refractive power, and the fourth lens group G4 has negative refractive power. The image capturing lens system includes eight lens elements ( 510 ,  520 ,  530 ,  540 ,  550 ,  560 ,  570  and  580 ) with no additional lens element disposed between each of the adjacent eight lens elements. 
     The focal length of the image capturing lens system is varied by changing axial distances between the four lens groups (G1, G2, G3, G4) in a zooming process. As shown in  FIG.  17    and  FIG.  18   , the second lens group G2 is moved relative to the first lens group G1 along an optical axis in the zooming process, and the third lens group G3 is moved relative to the first lens group G1 along the optical axis in the zooming process. Furthermore, the image capturing lens system has a short-focal-length end as shown in  FIG.  17    and a long-focal-length end as shown in  FIG.  18   . In addition, when the image capturing lens system is zooming from the short-focal-length end to the long-focal-length end, the second lens group G2 is moved along the optical axis toward the image side relative to the first lens group G1. It is noted that there is no relative motion between lens elements of each of the four lens groups in the zooming process. 
     The first lens element  510  with positive refractive power has an object-side surface  511  being convex in a paraxial region thereof and an image-side surface  512  being convex in a paraxial region thereof. The first lens element  510  is made of plastic material and has the object-side surface  511  and the image-side surface  512  being both aspheric. 
     The second lens element  520  with negative refractive power has an object-side surface  521  being concave in a paraxial region thereof and an image-side surface  522  being concave in a paraxial region thereof. The second lens element  520  is made of plastic material and has the object-side surface  521  and the image-side surface  522  being both aspheric. 
     The third lens element  530  with negative refractive power has an object-side surface  531  being concave in a paraxial region thereof and an image-side surface  532  being concave in a paraxial region thereof. The third lens element  530  is made of plastic material and has the object-side surface  531  and the image-side surface  532  being both aspheric. The third lens element  530  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The fourth lens element  540  with positive refractive power has an object-side surface  541  being convex in a paraxial region thereof and an image-side surface  542  being convex in a paraxial region thereof. The fourth lens element  540  is made of plastic material and has the object-side surface  541  and the image-side surface  542  being both aspheric. The fourth lens element  540  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The fifth lens element  550  with negative refractive power has an object-side surface  551  being concave in a paraxial region thereof and an image-side surface  552  being convex in a paraxial region thereof. The fifth lens element  550  is made of plastic material and has the object-side surface  551  and the image-side surface  552  being both aspheric. The fifth lens element  550  has at least one inflection point in an off-axis region thereof. 
     The sixth lens element  560  with negative refractive power has an object-side surface  561  being concave in a paraxial region thereof and an image-side surface  562  being concave in a paraxial region thereof. The sixth lens element  560  is made of plastic material and has the object-side surface  561  and the image-side surface  562  being both aspheric. The sixth lens element  560  has at least one inflection point in an off-axis region thereof. 
     The seventh lens element  570  with positive refractive power has an object-side surface  571  being convex in a paraxial region thereof and an image-side surface  572  being convex in a paraxial region thereof. The seventh lens element  570  is made of plastic material and has the object-side surface  571  and the image-side surface  572  being both aspheric. The seventh lens element  570  has at least one inflection point in an off-axis region thereof. 
     The eighth lens element  580  with negative refractive power has an object-side surface  581  being concave in a paraxial region thereof and an image-side surface  582  being convex in a paraxial region thereof. The eighth lens element  580  is made of plastic material and has the object-side surface  581  and the image-side surface  582  being both aspheric. The eighth lens element  580  has at least one inflection point and at least one critical point in an off-axis region thereof. 
     The filter  590  is made of glass material and located between the eighth lens element  580  and the image surface  595 , and will not affect the focal length of the image capturing lens system. The image sensor  599  is disposed on or near the image surface  595 . 
     In this embodiment, one of various focusing states of the image capturing lens system is provided, and the focusing state of the image capturing lens system is a state where the image capturing lens system focuses on an imaged object located at infinity. 
     The detailed optical data of the 5th embodiment are shown in Table 13 and Table 14, and the aspheric surface data are shown in Table 15 below. 
     
       
         
           
               
             
               
                 TABLE 13 
               
             
            
               
                   
               
               
                 5th Embodiment 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Surface # 
                   
                 Curvature Radius 
                 Thickness 
                 Material 
                 Index 
                 Abbe # 
                 Focal Length 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 Object 
                 Plano 
                 Infinity 
                   
               
               
                 1 
                 Stop 
                 Plano 
                 −0.854  
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 2 
                 Lens 1 
                 4.048 
                 (ASP) 
                 1.900 
                 Plastic 
                 1.545 
                 56.1 
                 5.02 
               
               
                 3 
                   
                 −7.040 
                 (ASP) 
                 0.073 
               
               
                 4 
                 Lens 2 
                 −15.563 
                 (ASP) 
                 0.306 
                 Plastic 
                 1.669 
                 19.5 
                 −13.35 
               
               
                 5 
                   
                 21.131 
                 (ASP) 
                 D5  
               
               
                 6 
                 Lens 3 
                 −3.329 
                 (ASP) 
                 0.300 
                 Plastic 
                 1.544 
                 56.0 
                 −5.49 
               
               
                 7 
                   
                 30.163 
                 (ASP) 
                 0.523 
               
               
                 8 
                 Lens 4 
                 18.765 
                 (ASP) 
                 1.900 
                 Plastic 
                 1.669 
                 19.5 
                 6.38 
               
               
                 9 
                   
                 −5.300 
                 (ASP) 
                 −0.075  
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 10 
                 Ape. Stop 
                 Plano 
                 0.127 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 11 
                 Lens 5 
                 −4.716 
                 (ASP) 
                 1.900 
                 Plastic 
                 1.669 
                 19.5 
                 −22.90 
               
               
                 12 
                   
                 −7.913 
                 (ASP) 
                 D12 
               
               
                 13 
                 Lens 6 
                 −8.675 
                 (ASP) 
                 1.900 
                 Plastic 
                 1.669 
                 19.5 
                 −6.52 
               
               
                 14 
                   
                 9.545 
                 (ASP) 
                 0.030 
               
               
                 15 
                 Lens 7 
                 4.294 
                 (ASP) 
                 1.900 
                 Plastic 
                 1.544 
                 56.0 
                 3.51 
               
               
                 16 
                   
                 −2.896 
                 (ASP) 
                 D16 
               
               
                 17 
                 Lens 8 
                 −1.311 
                 (ASP) 
                 0.318 
                 Plastic 
                 1.544 
                 56.0 
                 −4.87 
               
               
                 18 
                   
                 −2.816 
                 (ASP) 
                 0.500 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 19 
                 Filter 
                 Plano 
                 0.210 
                 Glass 
                 1.517 
                 64.2 
                 — 
               
               
                 20 
                   
                 Plano 
                 1.995 
               
               
                 21 
                 Image 
                 Plano 
                 — 
               
               
                   
               
               
                 Note: 
               
               
                 Reference wavelength is 587.6 nm (d-line). 
               
               
                 An effective radius of the stop 501 (Surface 1) is 2.455 mm. 
               
            
           
         
       
     
     The definitions of these parameters shown in Table 14 are the same as those stated in the 1st embodiment with corresponding values for the 5th embodiment, so an explanation in this regard will not be provided again. 
     Moreover, these parameters can be calculated from Table 13 and Table 15 as the following values and satisfy the following conditions: 
     
       
         
           
               
             
               
                 TABLE 14 
               
               
                   
               
               
                 5th Embodiment 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                   
                 Short-focal-length End 
                 Long-focal-length End 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 f [mm] 
                 10.04 
                 14.97 
               
               
                   
                 Fno 
                 3.46 
                 3.54 
               
               
                   
                 HFOV [deg.] 
                 13.8 
                 9.6 
               
               
                   
                 D5 [mm] 
                 0.121 
                 1.443 
               
               
                   
                 D12 [mm] 
                 1.011 
                 1.189 
               
               
                   
                 D16 [mm] 
                 1.625 
                 0.105 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 (Vi/Ni)min 
                 11.65 
                 fG3/fG4 
                 −1.06 
               
               
                   
                 V1 + V6 + V8 
                 131.5 
                 fL/fS 
                 1.49 
               
               
                   
                 TDL/fL 
                 0.92 
                 fS/EPDS 
                 3.46 
               
               
                   
                 |BLL/BLS − 1| 
                 0.00E+00 
                 fS/fG1 
                 1.39 
               
               
                   
                 |dTG34|/(TG3 + TG4) 
                 0.37 
                 fS/fG2 
                 −0.38 
               
               
                   
                 |TDL/TDS − 1| 
                 1.44E−03 
                 fS/fG3 
                 1.94 
               
               
                   
                 dTG12/dTG23 
                 7.43 
                 fS/fG4 
                 −2.06 
               
               
                   
                 dTG12/TG2 
                 0.28 
                 HFOVL [deg.] 
                 9.6 
               
               
                   
                 TG1/TG2 
                 0.49 
                 HFOVS [deg.] 
                 13.8 
               
               
                   
                 TG2/TG3 
                 1.22 
                 Y11L/ImgHL 
                 0.98 
               
               
                   
                 TG3/TG4 
                 12.04 
                 Y11L/Y82L 
                 1.18 
               
               
                   
                 f1/f3 
                 −0.91 
                 Y11S/ImgHS 
                 0.98 
               
               
                   
                 f4/f5 
                 −0.28 
                 Y11S/Y82S 
                 1.23 
               
               
                   
                 fG1/fG2 
                 −0.27 
                 — 
                 — 
               
               
                   
                   
               
            
           
         
       
     
     In the 5th embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment, so an explanation in this regard will not be provided again. 
     
       
         
           
               
             
               
                 TABLE 15 
               
               
                   
               
               
                 Aspheric Coefficients 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Surface # 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
               
               
                   
               
               
                 k = 
                 −5.5813E−01  
                 −3.8152E+01 
                  2.8032E+01 
                 −3.1906E+01 
                 −1.7773E+01 
                  0.0000E+00 
               
               
                 A4 = 
                 1.4138E−03 
                  4.4387E−04 
                 −7.8188E−03 
                 −1.9761E−02 
                  8.9512E−02 
                  1.3439E−01 
               
               
                 A6 = 
                 5.4871E−05 
                 −3.3864E−03 
                 −3.7638E−03 
                  3.5416E−03 
                 −5.7438E−02 
                 −7.0125E−02 
               
               
                 A8 = 
                 3.7883E−06 
                  1.7198E−03 
                  3.3709E−03 
                  4.7579E−04 
                  2.7337E−02 
                  2.8873E−02 
               
               
                 A10 = 
                 4.9914E−07 
                 −3.1794E−04 
                 −8.4193E−04 
                 −2.2854E−04 
                 −8.7810E−03 
                 −5.8497E−03 
               
               
                 A12 = 
                 9.4446E−08 
                  2.1261E−05 
                  9.0496E−05 
                  2.2330E−05 
                  1.5891E−03 
                 −1.1792E−04 
               
               
                 A14 = 
                 — 
                 — 
                 −3.3161E−06 
                 — 
                 −1.2298E−04 
                 — 
               
               
                   
               
               
                 Surface # 
                 8 
                 9 
                 11 
                 12 
                 13 
                 14 
               
               
                   
               
               
                 k = 
                  0.0000E+00 
                  0.0000E+00 
                 0.0000E+00 
                 0.0000E+00 
                  1.1946E+01 
                  0.0000E+00 
               
               
                 A4 = 
                 −2.5147E−02 
                 −6.9305E−02 
                 −3.6439E−02  
                 2.4012E−02 
                  1.9405E−02 
                 −1.6812E−03 
               
               
                 A6 = 
                  8.0730E−03 
                  8.5558E−02 
                 7.8446E−02 
                 −4.6833E−03  
                 −4.8018E−03 
                  1.4020E−03 
               
               
                 A8 = 
                 −3.6854E−03 
                 −5.5479E−02 
                 −5.4832E−02  
                 7.3599E−04 
                 −3.2703E−04 
                 −4.2961E−04 
               
               
                 A10 = 
                  2.0457E−03 
                  1.3742E−02 
                 1.2889E−02 
                 −2.1978E−03  
                  5.3012E−04 
                  5.3686E−05 
               
               
                 A12 = 
                 −8.3746E−04 
                 −4.8456E−04 
                 — 
                 1.5367E−03 
                 −8.8501E−05 
                 −5.5102E−06 
               
               
                 A14 = 
                 — 
                 — 
                 — 
                 −3.2380E−04  
                 — 
                 — 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Surface # 
                 15 
                 16 
                 17 
                 18 
               
               
                   
                   
               
               
                   
                 k = 
                 0.0000E+00 
                 −2.2918E+00 
                 −6.8251E−01 
                 −1.0435E+00 
               
               
                   
                 A4 = 
                 −1.3325E−02  
                 −5.2284E−03 
                  2.6280E−01 
                  2.0853E−01 
               
               
                   
                 A6 = 
                 3.3180E−03 
                 −4.9009E−04 
                 −1.6909E−01 
                 −1.2521E−01 
               
               
                   
                 A8 = 
                 −4.7268E−04  
                  7.0878E−04 
                  8.7891E−02 
                  5.3682E−02 
               
               
                   
                 A10 = 
                 2.5079E−05 
                 −3.0003E−04 
                 −3.1470E−02 
                 −1.6218E−02 
               
               
                   
                 A12 = 
                 — 
                  7.9436E−05 
                  7.2828E−03 
                  3.1851E−03 
               
               
                   
                 A14 = 
                 — 
                 −1.0909E−05 
                 −9.6252E−04 
                 −3.6064E−04 
               
               
                   
                 A16 = 
                 — 
                  6.1686E−07 
                  5.5283E−05 
                  1.7730E−05 
               
               
                   
                   
               
            
           
         
       
     
     6th Embodiment 
       FIG.  21    is one perspective view of an electronic device according to the 6th embodiment of the present disclosure.  FIG.  22    is another perspective view of the electronic device in  FIG.  21   .  FIG.  23    is a cross-sectional view of two image capturing units of the electronic device in  FIG.  21   . 
     In this embodiment, an electronic device  20  is a smartphone including an image capturing unit  10 , an image capturing unit  10   a , an image capturing unit  10   b , an image capturing unit  10   c , an image capturing unit  10   d , an image capturing unit  10   e , a flash module  21 , a display unit  22 , a focus assist module, an image signal processor and an image software processor. 
     In this embodiment, the image capturing unit  10  is a camera module including a lens unit, a driving device, an image sensor and an image stabilizer. The lens unit includes the image capturing lens system disclosed in the 1st embodiment, a barrel and a holder member. However, the lens unit may alternatively be provided with the image capturing lens system disclosed in other embodiments, and the present disclosure is not limited thereto. In addition, the image capturing unit  10  is a telephoto image capturing unit configured with a light-folding element LF6, and the light-folding element LF6 is disposed on the object side of the first lens element. Therefore, it is favorable for adjusting light travelling direction and folding optical axis, so that the total track length of the image capturing unit  10  and the thickness of the electronic device  20  are not restricted by each other. The imaging light converges in the lens unit of the image capturing unit  10  to generate an image with the driving device utilized for image zooming or focusing on the image sensor, and the generated image is then digitally transmitted to other electronic component for further processing. 
     The driving device can have zooming functionality or auto focusing functionality, and different driving configurations can be obtained through the usages of screws, voice coil motors (VCM) such as spring type or ball type, micro electro-mechanical systems (MEMS), piezoelectric systems, or shape memory alloy materials. The driving device is favorable for obtaining a better imaging position of the lens unit, so that a clear image of the imaged object can be captured by the lens unit with different object distances. The image sensor (for example, CCD or CMOS), which can feature high photosensitivity and low noise, is disposed on the image surface of the image capturing lens system to provide higher image quality. 
     The image stabilizer, such as an accelerometer, a gyro sensor and a Hall Effect sensor, is configured to work with the driving device to provide optical image stabilization (OIS). The driving device working with the image stabilizer is favorable for compensating for pan and tilt of the lens unit to reduce blurring associated with motion during exposure. In some cases, the compensation can be provided by electronic image stabilization (EIS) with image processing software, thereby improving image quality while in motion or low-light conditions. 
     The image capturing units  10 ,  10   a ,  10   b  are disposed on the same side of the electronic device  20 , and the image capturing units  10   c ,  10   d ,  10   e  and the display unit  22  are disposed on the opposite side of the electronic device  20 . Each of the image capturing units  10   a ,  10   b ,  10   c ,  10   d ,  10   e  can have a configuration similar to that of the image capturing unit  10 , so the details in this regard will not be provided again. The image capturing unit  10   a  includes an optical lens assembly and an image sensor (their reference numerals are omitted). As shown in  FIG.  23   , the optical lens assembly of the image capturing unit  10   a  has an optical axis OA6, and a movement direction D10 of lens groups of the image capturing unit  10  is perpendicular to the optical axis OA6; furthermore, the movement direction D10 of lens groups of the image capturing unit  10  is also perpendicular to an optical axis of the image capturing unit  10   b . Therefore, it is favorable for adjusting space arrangement so as to reduce the thickness of the electronic device. 
     The image capturing unit  10  is a telephoto image capturing unit configured with a light-folding element, the image capturing unit  10   a  is a telephoto image capturing unit, and the image capturing unit  10   b  is a wide angle image capturing unit. Half of a maximum field of view of the image capturing unit  10   a  ranges from 15 degrees to 30 degrees, and half of a maximum field of view of the image capturing unit  10   b  ranges from 30 degrees to 60 degrees. In other configurations, half of the maximum field of view of the image capturing unit  10   b  can range from 35 degrees to 50 degrees. The image capturing units  10 ,  10   a ,  10   b  have different fields of view, such that the electronic device  20  can have a larger zoom ratio for more applications. The abovementioned electronic device  20  has the three image capturing units  10 ,  10   a ,  10   b  on the same side, but the present disclosure is not limited thereto. In other configurations, the electronic device may have at least two image capturing units disposed on the same side or have at least three image capturing units disposed on the same side. 
     The image capturing unit  10   c  is a wide angle image capturing unit, the image capturing unit  10   d  is an ultra-wide-angle image capturing unit, and the image capturing unit  10   e  is a ToF (time of flight) image capturing unit, wherein the image capturing unit  10   e  can determine depth information of the imaged object. The image capturing units  10   c ,  10   d ,  10   e  and the display unit  22  are disposed on the same side of the electronic device  20 , such that the image capturing units  10   c ,  10   d ,  10   e  can be front-facing cameras of the electronic device  20  for taking selfies, but the present disclosure is not limited thereto. 
     The electronic device  20  includes multiple image capturing units  10 ,  10   a ,  10   b ,  10   c ,  10   d ,  10   e , but the present disclosure is not limited to the number and arrangement of image capturing units. 
     When a user captures images of an object, the light rays converge in the image capturing units  10 ,  10   a  or  10   b  to generate an image(s), and the flash module  21  is activated for light supplement. The focus assist module detects the object distance of the imaged object to achieve fast auto focusing. The image signal processor is configured to optimize the captured image to improve image quality. The light beam emitted from the focus assist module can be either conventional infrared or laser. In addition, the light rays may converge in the image capturing units  10   c ,  10   d  or  10   e  to generate an image(s). The display unit  22  can be a touch screen, and the user is able to interact with the display unit  22  and the image software processor having multiple functions to capture images and complete image processing. Alternatively, the user may capture images via a physical button. The image processed by the image software processor can be displayed on the display unit  22 . 
     7th Embodiment 
       FIG.  24    is a perspective view of an electronic device according to the 7th embodiment of the present disclosure. 
     In this embodiment, an electronic device  30  is a smartphone including an image capturing unit  10   f , an image capturing unit  10   g , an image capturing unit  10   h , an image capturing unit  10   i , an image capturing unit  10   j , an image capturing unit  10   k , an image capturing unit  10   m , an image capturing unit  10   n , an image capturing unit  10   p , a flash module  31 , a focus assist module, an image signal processor, a display unit and an image software processor (not shown). The image capturing units  10   f ,  10   g ,  10   h ,  10   i ,  10   j ,  10   k ,  10   m ,  10   n ,  10   p  are disposed on the same side of the electronic device  30 , and the display unit is disposed on the opposite side of the electronic device  30 . Each of the image capturing units  10   f ,  10   g ,  10   h ,  10   i ,  10   j ,  10   k ,  10   m ,  10   n ,  10   p  can include the image capturing lens system of the present disclosure and can have a configuration similar to that of the image capturing unit  10 , so the details in this regard will not be provided again. 
     The image capturing units  10   f ,  10   g  are telephoto image capturing units configured with light-folding element(s), the image capturing units  10   h ,  10   i  are telephoto image capturing units, the image capturing units  10   j ,  10   k  are wide angle image capturing units, the image capturing units  10   m ,  10   n  are ultra-wide-angle image capturing units, and the image capturing unit  10   p  is a ToF image capturing unit. The image capturing units  10   f ,  10   g  with light-folding element(s) may respectively have a configuration, for example, similar to that as shown in  FIG.  27   ,  FIG.  28    or  FIG.  29   , and a description in this regard will not be provided again. In this embodiment, the image capturing units  10   f ,  10   g ,  10   h ,  10   i ,  10   j ,  10   k ,  10   m ,  10   n ,  10   p  have different fields of view, such that the electronic device  30  has various magnification ratios so as to meet the requirement of optical zoom functionality. The electronic device  30  includes multiple image capturing units  10   f ,  10   g ,  10   h ,  10   i ,  10   j ,  10   k ,  10   m ,  10   n ,  10   p , but the present disclosure is not limited to the number and arrangement of image capturing units. 
     The smartphone in this embodiment is only exemplary for showing the image capturing unit of the present disclosure installed in an electronic device, and the present disclosure is not limited thereto. The image capturing unit can be optionally applied to optical systems with a movable focus. Furthermore, the image capturing lens system of the image capturing unit features good capability in aberration corrections and high image quality, and can be applied to 3D (three-dimensional) image capturing applications, in products such as digital cameras, mobile devices, digital tablets, smart televisions, network surveillance devices, dashboard cameras, vehicle backup cameras, multi-camera devices, image recognition systems, motion sensing input devices, wearable devices and other electronic imaging devices. 
     The foregoing description, for the purpose of explanation, has been described with reference to specific embodiments. It is to be noted that TABLES 1-15 show different data of the different embodiments; however, the data of the different embodiments are obtained from experiments. The embodiments were chosen and described in order to best explain the principles of the disclosure and its practical applications, to thereby enable others skilled in the art to best utilize the disclosure and various embodiments with various modifications as are suited to the particular use contemplated. The embodiments depicted above and the appended drawings are exemplary and are not intended to be exhaustive or to limit the scope of the present disclosure to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings.