Patent Publication Number: US-9851529-B2

Title: Imaging lens and imaging apparatus

Description:
BACKGROUND OF THE INVENTION 
     Technical Field 
     The present invention relates to an imaging lens, and more particularly to an imaging lens that is favorably used for an electronic camera such as a digital camera, a broadcasting camera, a surveillance camera, a movie camera, and the like. 
     Further, the present invention relates to an imaging apparatus as described above. 
     Description of the Related Art 
     Conventionally, imaging apparatuses such as video cameras, electronic still cameras, and the like that utilize image sensors such as a CCD (Charge Coupled Device) and a CMOS (Complementary Metal Oxide Semiconductor) as a recording medium are widely put to practical uses. Further, imaging lenses disclosed in Patent Documents 1 and 2 (Japanese Unexamined Patent Publication No. 2001-330771 and Japanese Unexamined Patent Publication No. 5 (1993)-224119) are known as imaging lenses which are favorably applied for use in such imaging apparatuses. 
     The imaging lens disclosed in Patent Document 1 consists of a first lens group having a positive refractive power, an aperture stop, and a second lens group having a positive refractive power in this order from the object side, wherein the first lens group includes of five lenses in which a positive lens, a negative lens, a negative lens, a positive lens, and a positive lens are disposed in this order from the object side. 
     Further, the imaging lens disclosed in Patent Document 2 consists of a first lens group which is constituted by three positive meniscus lenses, a second lens group which is constituted by a negative meniscus lens, an aperture stop, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power in this order from the object side. 
     SUMMARY OF THE INVENTION 
     The imaging lens disclosed in Patent Document 1 is deemed to have a problem such that correcting chromatic aberrations favorably is difficult. 
     The imaging lens disclosed in Patent Document 2 is also deemed to have a problem such that widening the angle of view is difficult because three lenses which are the first lens through the third lens are all positive lenses. 
     The present invention has been developed in view of the above circumstances. It is an object of the present invention to provide an imaging lens which is capable of correcting chromatic aberrations satisfactorily and in which an angle of view can be easily widened as well as an imaging apparatus. 
     A first imaging lens according to the present invention substantially consists of a first lens group having a positive refractive power and a second lens group having a positive refractive power in this order from the object side, wherein 
     focusing is performed by moving the entirety of the second lens group along the optical axis; 
     the first lens group comprises a first lens having a positive refractive power which is disposed on the most-object side, a second lens having a negative refractive power which is disposed next to the first lens on the image side, a third lens having a negative refractive power which is disposed next to the second lens on the image side, a fourth lens having a positive refractive power which is disposed next to the third lens on the image side, and a fifth lens having a positive refractive power which is disposed next to the fourth lens on the image side; and 
     the imaging lens satisfies conditional formula (1):
 
2.0&lt; vd 2/ vd 3  (1), where
 
vd 2 : the Abbe number of the second lens with respect to the d-line, and
 
vd 3 : the Abbe number of the third lens with respect to the d-line.
 
     Here, the above expression “substantially consisting of” intends to mean that lenses substantially without any refractive power; optical elements other than lenses such as stops, cover glasses, filters and the like; lens flanges; lens barrels; image sensors; and mechanical parts such as image stabilization mechanisms, and the like; in addition to the first lens group and the second lens group listed above. Further, the above expression “the second lens having a negative refractive power which is disposed next to the first lens on the image side” intends to mean that the first lens and the second lens are arranged in such a positional relationship without disposing other lenses therebetween. The same applies to the lenses which follow after the second lens. Further, regarding the powers of the lenses below, “having a positive refractive power” will simply be described as “positive” and “having a negative refractive power” will simply be described as “negative”, unless particularly necessary. 
     Note that it is desirable for the lower limit of the condition (that is, the equation; the same applies hereinafter), the numerical range of which is defined by conditional formula (1), to be 2.5, and more preferably 3.0. Further, it is preferable for the upper limit of this condition to be 5.0. That is, it is desirable for this condition to satisfy the conditional formulas below:
 
2.5&lt; vd 2/ vd 3  (1-1)
 
3.0&lt; vd 2/ vd 3  (1-2)
 
2.0&lt; vd 2/ vd 3&lt;5.0  (1-3).
 
Further, it is more preferable for the upper limit of the value of vd 2 /vd 3  to be 4.0.
 
     A second imaging lens of the present invention substantially consists of a first lens group having a positive refractive power and a second lens group having a positive refractive power in this order from the object side, wherein 
     focusing is performed by moving the entirety of the second lens group along the optical axis; and 
     the most-image-side lens of the first lens group, a lens which is second from the most-image side in the first lens group, and a lens which is third from the most-image side in the first lens group are all meniscus lenses with convex surfaces toward the image side. 
     The imaging lens of the present invention can take a preferred embodiment in which this second imaging lens and the first imaging lens are combined together. 
     Note that in the second imaging lens described above, it is desirable for the most-image-side lens of the first lens group to be a positive lens, for a lens which is second from the most-image side in the first lens group to be a positive lens, and for a lens which is third from the most-image side in the first lens group to be a negative lens. 
     Further, it is desirable for the first imaging lens and the second imaging lens according to the present invention (hereinafter, when referring to both of these imaging lenses, the phrase “imaging lens according to the present invention” or “imaging lens of the present invention” will be employed) to include an aperture stop between the first lens group and the second lens group. 
     In the imaging lens of the present invention, it is desirable for the first lens group to include the positive first lens which is disposed on the most-object side, the negative second lens which is disposed next to the first lens on the image side, the negative third lens which is disposed next to the second lens on the image side, the positive fourth lens which is disposed next to the third lens on the image side, the positive fifth lens which is disposed next to the fourth lens on the image side, a negative sixth lens which is disposed next to the fifth lens on the image side, a negative seventh lens which is disposed next to the sixth lens on the image side, a positive eighth lens which is disposed next to the seventh lens on the image side, and a positive ninth lens which is disposed next to the eighth lens on the image side. 
     It is desirable for the imaging lens of the present invention to satisfy conditional formula (2) below:
 
1.0&lt; FA/FB&lt; 8.0  (2), where
 
FA: the focal length of the first lens group, and
 
FB: the focal length of the second lens group.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (2), it is more preferable for conditional formula (2-1) below to be satisfied, even more preferable for conditional formula (2-2) below to be satisfied, and still more preferable for conditional formula (2-3) below to be satisfied:
 
1.5&lt; FA/FB&lt; 7.0  (2-1)
 
2.0&lt; FA/FB&lt; 6.0  (2-2)
 
2.2&lt; FA/FB&lt; 5.0  (2-3).
 
     It is desirable for the imaging lens of the present invention in which the first lens group includes the first lens disposed on the most-object side to satisfy conditional formula (3) below:
 
1&lt; f 1/ f&lt; 6  (3), where
 
f 1 : the focal length of the first lens, and
 
f: the focal length of the entire system.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (3), it is more preferable for conditional formula (3-1) below to be satisfied, even more preferable for conditional formula (3-2) below to be satisfied, and still more preferable for conditional formula (3-3) below to be satisfied:
 
2&lt; f 1/ f&lt; 5.5  (3-1)
 
2.5&lt; f 1/ f&lt; 4.5  (3-2)
 
3&lt; f 1/ f&lt; 5  (3-3).
 
     In the imaging lens of the present invention, it is desirable for the most-image-side lens of the second lens group to be a positive lens and for conditional formula (4) below to be satisfied:
 
0.5&lt;( RLF+RLB )/( RLF−RLB )&lt;3.0  (4), where
 
RLF: the radius of curvature of the object-side surface of the most-image-side lens of the second lens group, and
 
RLB: the radius of curvature of the image-side surface of the most-image-side lens of the second lens group.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (4), it is more preferable for conditional formula (4-1) below to be satisfied, even more preferable for conditional formula (4-2) below to be satisfied, and still more preferable for conditional formula (4-3) below to be satisfied:
 
0.5&lt;( RLF+RLB )/( RLF−RLB )&lt;2.5  (4-1)
 
0.55&lt;( RLF+RLB )/( RLF−RLB )&lt;2.0  (4-2)
 
0.6&lt;( RLF+RLB )/( RLF−RLB )&lt;1.5  (4-3).
 
     In the imaging lens of the present invention, it is desirable for a lens which is second from the most-image side in the second lens group to be a positive lens and for conditional formula (5) below to be satisfied:
 
0.3&lt;( RL 2 F+RL 2 B )/( RL 2 F−RL 2 B )&lt;3.0  (5), where
 
RL 2 F: the radius of curvature of the object-side surface of the lens which is second from the most-image side in the second lens group, and
 
RL 2 B: the radius of curvature of the image-side surface of the lens which is second from the most-image side in the second lens group.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (5), it is more preferable for conditional formula (5-1) below to be satisfied, even more preferable for conditional formula (5-2) below to be satisfied, and still more preferable for conditional formula (5-3) below to be satisfied:
 
0.8&lt;( RL 2 F+RL 2 B )/( RL 2 F−RL 2 B )&lt;2.5  (5-1)
 
1.2&lt;( RL 2 F+RL 2 B )/( RL 2 F−RL 2 B )&lt;2.0  (5-2)
 
1.4&lt;( RL 2 F+RL 2 B )/( RL 2 F−RL 2 B )&lt;1.8  (5-3).
 
     In the imaging lens of the present invention, it is desirable for both the most-image-side lens and the lens which is second from the most-image side in the second lens group to be lenses with convex surfaces toward the image side. 
     In the imaging lens of the present invention, it is desirable for the most-image-side lens in the first lens group to be a positive meniscus lens with a convex surface toward the image side. 
     In the imaging lens of the present invention, it is desirable for the first lens group to include the first lens which is disposed on the most-object side, the second lens which is disposed next to the first lens on the image side, the third lens which is disposed next to the second lens on the image side, and the fourth lens which is disposed next to the third lens on the image side; and for conditional formula (6) below to be satisfied:
 
−3.0&lt; f 1234/ f&lt;− 0.5  (6), where
 
f 1234 : the combined focal length of the first lens through the fourth lens, and
 
f: the focal length of the entire system.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (6), it is more preferable for conditional formula (6-1) below to be satisfied, even more preferable for conditional formula (6-2) below to be satisfied, and still more preferable for conditional formula (6-3) below to be satisfied:
 
−2.5&lt; f 1234/ f&lt;− 0.7  (6-1)
 
−2.0&lt; f 1234/ f&lt;− 0.9  (6-2)
 
−1.9&lt; f 1234/ f&lt;− 1.2  (6-3).
 
     In the imaging lens of the present invention, it is desirable for the first lens group to include the first lens which is disposed on the most-object side, the second lens which is disposed next to the first lens on the image side, and the third lens which is disposed next to the second lens on the image side; and for conditional formula (7) below to be satisfied:
 
−3.0&lt; f 123/ f&lt;− 0.2  (7), where
 
f 123 : the combined focal length of the first lens through the third lens, and
 
f: the focal length of the entire system.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (7), it is more preferable for conditional formula (7-1) below to be satisfied, even more preferable for conditional formula (7-2) below to be satisfied, and still more preferable for conditional formula (7-3) below to be satisfied:
 
−2.5&lt; f 123/ f&lt;− 0.4  (7-1)
 
−2.0&lt; f 123/ f&lt;− 0.5  (7-2)
 
−1.5&lt; f 123/ f&lt;− 0.7  (7-3).
 
     In the imaging lens of the present invention, it is desirable for the most-object-side lens of the first lens group to be a biconvex lens. 
     In the imaging lens of the present invention, it is desirable for the first lens group to include the first lens which is disposed on the most-object side, the second lens which is disposed next to the first lens on the image side, the third lens which is disposed next to the second lens on the image side, the fourth lens which is disposed next to the third lens on the image side, and the fifth lens which is disposed next to the fourth lens on the image side; and for both the Abbe number vd 4  of the fourth lens with respect to the d-line and the Abbe number vd 5  of the fifth lens with respect to the d-line to be less than or equal to 45. 
     It is desirable for the imaging lens of the present invention to satisfy conditional formula (8) below:
 
2&lt; FA/f&lt; 12.0  (8), where
 
FA: the focal length of the first lens group, and
 
f: the focal length of the entire system.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (8), it is more preferable for conditional formula (8-1) below to be satisfied, even more preferable for conditional formula (8-2) below to be satisfied, and still more preferable for conditional formula (8-3) below to be satisfied:
 
3&lt; FA/f&lt; 10.0  (8-1)
 
4&lt; FA/f&lt; 9.0  (8-2)
 
5&lt; FA/f&lt; 8.0  (8-3).
 
     It is desirable for the imaging lens of the present invention to satisfy conditional formula (9) below:
 
0.5&lt; FB/f&lt; 3.0  (9), where
 
FB: the focal length of the second lens group, and
 
f: the focal length of the entire system.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (9), it is more preferable for conditional formula (9-1) below to be satisfied, even more preferable for conditional formula (9-2) below to be satisfied, and still more preferable for conditional formula (9-3) below to be satisfied:
 
0.8&lt; FB/f&lt; 2.8  (9-1)
 
1.0&lt; FB/f&lt; 2.3  (9-2)
 
1.4&lt; FB/f&lt; 2.1  (9-3).
 
     In the imaging lens of the present invention, it is desirable for the first lens group to include he first lens which is disposed on the most-object side, the second lens which is disposed next to the first lens on the image side, the third lens which is disposed next to the second lens on the image side, and the fourth lens which is disposed next to the third lens on the image side; and for conditional formula (10) below to be satisfied:
 
1.5&lt;( R 7+ R 8)/( R 7− R 8)&lt;5.0  (10), where
 
R 7 : the radius of curvature of the object-side surface of the fourth lens, and
 
R 8 : the radius of curvature of the image-side surface of the fourth lens.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (10), it is more preferable for conditional formula (10-1) below to be satisfied, even more preferable for conditional formula (10-2) below to be satisfied, and still more preferable for conditional formula (10-3) below to be satisfied:
 
2.0&lt;( R 7+ R 8)/( R 7− R 8)&lt;4.8  (10-1)
 
2.6&lt;( R 7+ R 8)/( R 7− R 8)&lt;4.5  (10-2)
 
2.8&lt;( R 7+ R 8)/( R 7− R 8)&lt;4.0  (10-3).
 
     In the imaging lens of the present invention, it is desirable for the first lens group to include the first lens which is disposed on the most-object side, the second lens which is disposed next to the first lens on the image side, the third lens which is disposed next to the second lens on the image side, and the fourth lens which is disposed next to the third lens on the image side; and for conditional formula (11) below to be satisfied:
 
0.1&lt; D 6/ f&lt; 1.5  (11), where
 
D 6 : the distance between the third lens and the fourth lens, and
 
f: the focal length of the entire system.
 
     Here, the above expression “the distance between the third lens and the fourth lens” refers to the distance between the image-side surface of the third lens and the object-side surface of the fourth lens. 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (11), it is more preferable for conditional formula (11-1) below to be satisfied, even more preferable for conditional formula (11-2) below to be satisfied, and still more preferable for conditional formula (11-3) below to be satisfied:
 
0.15&lt; D 6/ f&lt; 1.3  (11-1)
 
0.2&lt; D 6/ f&lt; 1.0  (11-2)
 
0.22&lt; D 6/ f&lt; 0.8  (11-3).
 
     In the imaging lens of the present inventio, it is desirable for the first lens group to include the first lens which is disposed on the most-object side, the second lens which is disposed next to the first lens on the image side, and the third lens which is disposed next to the second lens on the image side; and for conditional formula (12) below to be satisfied:
 
0.1&lt; D 4/ f&lt; 1.5  (12), where
 
D 4 : the distance between the second lens and the third lens, and
 
f: the focal length of the entire system.
 
     Here, the above expression “the distance between the second lens and the third lens” refers to the distance between the image-side surface of the second lens and the object-side surface of the third lens. 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (12), it is more preferable for conditional formula (12-1) below to be satisfied, even more preferable for conditional formula (12-2) below to be satisfied, and still more preferable for conditional formula (12-3) below to be satisfied:
 
0.15&lt; D 4/ f&lt; 1.2  (12-1)
 
0.2&lt; D 4/ f&lt; 1.0  (12-2)
 
0.21&lt; D 4/ f&lt; 0.7  (12-3).
 
     In the imaging lens of the present invention, it is desirable for the first lens group to include the first lens disposed on the most-object side and the second lens disposed next to the first lens on the image side; and for conditional formula (13) below to be satisfied:
 
−3.0&lt; f 1/ f 2&lt;−0.05  (13), where
 
f 1 : the focal length of the first lens, and
 
f 2 : the focal length of the second lens.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (13), it is more preferable for conditional formula (13-1) below to be satisfied, even more preferable for conditional formula (13-2) below to be satisfied, and still more preferable for conditional formula (13-3) below to be satisfied:
 
−1.8&lt; f 1/ f 2&lt;−0.2  (13-1)
 
−1.5&lt; f 1/ f 2&lt;−0.25  (13-2)
 
−1.0&lt; f 1/ f 2&lt;−0.25  (13-3).
 
     In the imaging lens of the present invention, it is desirable for the first lens group to include the first lens which is disposed on the most-object side; and for conditional formula (14) to be satisfied:
 
2.0&lt; L/f&lt; 8.0  (14), where
 
L: the distance from the object-side surface of the first lens to the imaging plane (back focus corresponds to an air converted length), and
 
f: the focal length of the entire system.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (14), it is more preferable for conditional formula (14-1) below to be satisfied, even more preferable for conditional formula (14-2) below to be satisfied, and still more preferable for conditional formula (14-3) below to be satisfied:
 
2.5&lt; L/f&lt; 7.5  (14-1)
 
3.0&lt; L/f&lt; 7.0  (14-2)
 
3.5&lt; L/f&lt; 6.0  (14-3).
 
     It is desirable for the imaging lens of the present invention to satisfy conditional formula (15) below:
 
0.3&lt; Bf/f&lt; 3.0  (15), where
 
Bf: back focus (air converted length), and
 
f: the focal length of the entire system.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (15), it is more preferable for conditional formula (15-1) below to be satisfied, even more preferable for conditional formula (15-2) below to be satisfied, and still more preferable for conditional formula (15-3) below to be satisfied:
 
0.5&lt; Bf/f&lt; 2.5  (15-1)
 
0.8&lt; Bf/f&lt; 2.0  (15-2)
 
1.0&lt; Bf/f&lt; 1.8  (15-3).
 
     In the imaging lens of the present invention, it is desirable for the first lens group to include the first lens which is disposed on the most-object side and the second lens which is disposed next to the first lens on the image side; and for conditional formula (16) below to be satisfied:
 
−5.0&lt;( R 1+ R 2)/( R 1− R 2)&lt;−0.2  (16), where
 
R 1 : the radius of curvature of the object-side surface of the first lens, and
 
R 2 : the radius of curvature of the image-side surface of the second lens.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (16), it is more preferable for conditional formula (16-1) below to be satisfied, even more preferable for conditional formula (16-2) below to be satisfied, and still more preferable for conditional formula (16-3) below to be satisfied:
 
−4.0&lt;( R 1+ R 2)/( R 1− R 2)&lt;−0.3  (16-1)
 
−3.0&lt;( R 1+ R 2)/( R 1− R 2)&lt;−0.4  (16-2)
 
−2.0&lt;( R 1+ R 2)/( R 1− R 2)&lt;−0.6  (16-3).
 
     In the imaging lens of the present invention, it is desirable for the first lens group to include the first lens which is disposed on the most-object side, the second lens which is disposed next to the first lens on the image side, the third lens which is disposed next to the second lens on the image side, the fourth lens which is disposed next to the third lens on the image side, and the fifth lens which is disposed next to the fourth lens on the image side; and for conditional formula (17) below to be satisfied:
 
−5.0&lt;( R 9+ R 10)/( R 9− R 10)&lt;−0.2  (17), where
 
R 9 : the radius of curvature of the object-side surface of the fifth lens, and
 
R 10 : the radius of curvature of the image-side surface of the fifth lens.
 
     Note that with respect to the condition, the numerical range of which is defined by conditional formula (17), it is more preferable for conditional formula (17-1) below to be satisfied, even more preferable for conditional formula (17-2) below to be satisfied, and still more preferable for conditional formula (17-3) below to be satisfied:
 
−4.0&lt;( R 9+ R 10)/( R 9− R 10)&lt;−0.3  (17-1)
 
−3.0&lt;( R 9+ R 10)/( R 9− R 10)&lt;−0.4  (17-2)
 
−2.0&lt;( R 9+ R 10)/( R 9− R 10)&lt;−0.5  (17-3).
 
     Here, a preferred shape of each of the lenses which constitute the imaging lens of the present invention and the detailed configurations related thereto will be described. Note that the first lens through the ninth lens to be described later refer to lenses which are disposed in the order of the first, the second, the third . . . the ninth lens from the object side without disposing other lenses between the respective adjacent lenses as described above. The refractive power of each of the first lens through the ninth lens is not limited to the refractive power mentioned above. That is, the first lens through the ninth lens mentioned here define only the order in which the lenses are disposed. 
     It is desirable for the first lens group to include at least one cemented lens, particularly a cemented lens formed by cementing at least one positive lens and a negative lens together. 
     It is desirable for each of the first, the second, and the third lens from the most-image side in the first lens group to be a meniscus lens. 
     Further, it is desirable for each of the first, the second, and the third lens from the most-image side in the first lens group to be a lens with a convex surface toward the image side. 
     It is desirable for the most-image-side lens of the first lens group to be a positive meniscus lens. 
     It is desirable for the first lens to be a biconvex lens. 
     It is desirable for the absolute value of the radius of curvature of the object-side surface of the first lens to be smaller than the absolute value of the radius of curvature of the image-side surface of the first lens. 
     It is desirable for the second lens to be a concave meniscus lens with a convex surface toward the object side. 
     It is desirable for the third lens to be a biconcave lens. 
     It is desirable for the absolute value of the radius of curvature of the object-side surface of the third lens to be greater than the absolute value of the radius of curvature of the image-side surface of the third lens. 
     It is desirable for the fourth lens to be a positive lens. 
     It is desirable for the fourth lens to be a meniscus lens with a convex surface toward the image side. 
     It is desirable for the fifth lens to be a positive lens. 
     It is desirable for the fifth lens to be a lens with a convex surface toward the object side. 
     It is desirable for the fifth lens to a positive meniscus lens with a convex surface toward the object side or a planoconvex lens. 
     It is desirable for the sixth lens to be a negative lens. 
     Further, it is desirable for the sixth lens to be a biconcave lens. 
     It is desirable for the absolute value of the radius of curvature of the object-side surface of the sixthlens to be greater than the absolute value of the radius of curvature of the image-side surface of the sixth lens. 
     It is desirable for the seventh lens to be a meniscus lens with a concave surface toward the object side. 
     It is desirable for the seventh lens to be a negative lens. 
     It is desirable for the eighth lens to be a meniscus lens with a concave surface toward the object side. 
     It is desirable for the eighth lens to be a positive lens. 
     It is desirable for the seventh lens and the eighth lens to be cemented to each other. 
     It is desirable for the ninth lens to be a meniscus lens with a concave surface toward the object side. 
     It is desirable for the ninth lens to be a positive lens. 
     It is desirable for the second lens group to include at least one cemented lens. 
     Further, it is desirable for the second lens group to include a cemented lens formed by cementing at least one positive lens and a negative lens together. 
     Further, it is desirable for the second lens group to include at least two or more negative lenses. 
     It is desirable for the most-object-side lens of the second lens group to be a positive lens. 
     It is desirable for the most-object-side lens of the second lens group to be a biconvex lens. 
     It is desirable for the most-object-side lens of the second lens group to have the absolute value of the radius of curvature of the object-side surface which is smaller than the absolute value of the radius of curvature of the image-side surface. 
     It is desirable for the lens which is second from the object side in the second lens group to be a negative lens. 
     It is desirable for the lens which is third from the object side in the second lens group to be a positive lens. 
     It is desirable for the lens which is fourth from the object side in the second lens group to be a negative lens. 
     Further, it is desirable for the lens which is third from the object side in the second lens group and the lens which is fourth from the object side in the second lens group to be cemented to each other. 
     It is desirable for the lens which is fifth from the object side in the second lens group to be a positive lens. 
     It is desirable for the lens which is sixth from the object side in the second lens group to be a positive lens. 
     It is desirable for the most-image-side lens of the second lens group to be a positive lens. 
     The lens which is second from the most-image side in the second lens group may be a positive lens. 
     It is desirable for each of the most-image-side lens of the second lens group and the lens which is second from the most-image side in the second lens group to be a lens with a convex surface toward the image side. 
     It is desirable for all of the object-side surface of the most-object-side lens in the first lens group, the image-side surface of the most-image-side lens in the first lens group, the object-side surface of the most-object-side lens in the second lens group, and the image-side surface of the most-image-side lens in the second lens group to be convex surfaces. 
     Next, the Abbe number, the partial dispersion ratio, and the refractive index suitable for each of the lenses which constitute the imaging lens of the present invention will be described. Note that the Abbe numbers and the refractive indices defined in the imaging lens of the present invention are all with respect to the d-line, and the partial dispersion ratios are all with respect to the g-line and the F-line. The description thereof will be omitted below, unless particularly necessary. Further, the first lens through the eighth lens to be described below refer to lenses which are disposed in the order of the first, the second, the third . . . the eighth lens from the object side without disposing other lenses between the respective adjacent lenses as described above. In addition, the refractive power of each of the first lens through the eighth lens is not limited to the refractive power mentioned above. That is, the first lens through the eighth lens mentioned here define only the order in which the lenses are disposed. 
     First, it is desirable for the Abbe number of the first lens to be greater tha or equal to 30, and more preferably greater than or equal to 35. 
     It is desirable for the Abbe number of the second lens to be greater than or equal to 50, more preferably greater than or equal to 55, even more preferably greater than or equal to 60, and still more preferably greater than or equal to 65. 
     It is desirable for the Abbe number of the third lens to be less than or equal to 30, more preferably less than or equal to 28, and even more preferably less than or equal to 27. 
     It is desirable for the Abbe number of the third lens to be greater than or equal to 20. 
     Further, regarding the third lens, the Abbe number is preferably between 15 and 30, and the partial dispersion ratio is preferably greater than or equal to 0.6 and more preferably greater than or equal to 0.61. 
     It is desirable for the Abbe number of the fourth lens to be less than or equal to 40, and more preferably less than or equal to 35. 
     Further, regarding the fourth lens, the Abbe number is preferably between 22 and 40, and the partial dispersion ratio is preferably greater than or equal to 0.58. 
     It is desirable for the Abbe number of the fifth lens to be less than or equal to 40, and more preferably less than or equal to 35. 
     Further, regarding the fifth lens, the Abbe number is preferably between 22 and 40, and the partial dispersion ratio is preferably greater than or equal to 0.58. 
     It is desirable for the Abbe number of the sixth lens to be greater than or equal to 25, and more preferably greater than or equal to 30. 
     It is desirable for the Abbe number of the sixth lens to be less than or equal to 55, and more preferably less than or equal to 50. 
     It is desirable for the Abbe number of the seventh lens to be greater than or equal to 15, more preferably greater than or equal to 18, and even more preferably greater than or equal to 20. 
     It is desirable for the Abbe number of the seventh lens to be less than or equal to 33, more preferably less than or equal to 30, and even more preferably less than or equal to 28. 
     It is desirable for the Abbe number of the eighth lens to be greater than or equal to 50, more preferably greater than or equal to 55, even more preferably greater than or equal to 60, and still more preferably greater than or equal to 70. 
     It is desirable for the Abbe number of the most-image-side lens of the first lens group to be less than or equal to 40, more preferably less than or equal to 30, and even more preferably less than or equal to 28. 
     It is desirable for the Abbe number of the lens which is second from the most-image side in the first lens group to be greater than or equal to 50, more preferably greater than or equal to 55, even more preferably greater than or equal to 60, and still more preferably greater than or equal to 65. 
     It is desirable for the Abbe number of the lens which is third from the most-image side in the first lens group to be less than or equal to 30, more preferably less than or equal to 28, and even more preferably less than or equal to 26. 
     It is desirable for the Abbe number of the most-object-side lens of the second lens group to be greater than or equal to 30, more preferably greater than or equal to 35, and even more preferably greater than or equal to 38. 
     It is desirable for the Abbe number of the lens which is second from the most-object side in the second lens group to be greater than or equal to 20, and more preferably greater than or equal to 30. 
     It is desirable for the Abbe number of the lens which is third from the most-object side in the second lens group to be greater than or equal to 40, more preferably greater than or equal to 50, and even more preferably greater than or equal to 60. 
     It is desirable for the Abbe number of the lens which is fourth from the most-object side in the second lens group to be less than or equal to 30, more preferably less than or equal to 29, and even more preferably less than or equal to 28. 
     It is desirable for the Abbe number of the most-image-side lens of the second lens group to be greater than or equal to 40, more preferably greater than or equal to 45, and even more preferably greater than or equal to 50. 
     It is desirable for the Abbe number of the lens which is second from the most-image side in the second lens group to be greater than or equal to 40, more preferably greater than or equal to 45, and even more preferably greater than or equal to 48. 
     In the case that a cemeted lens is employed for the second lens group, it is desirable for the Abbe number of the positive lens which constitutes the cemented lens to be greater than or equal to 40, more preferably greater than or equal to 50, and even more preferably greater than or equal to 60. 
     In the case that a cemeted lens is employed for the second lens group, it is desirable for the Abbe number of the negative lens which constitutes the cemented lens to be less than or equal to 30, more preferably less than or equal to 29, and even more preferably less than or equal to 28. 
     It is desirable for the refractive index of the first lens to be greater than 1.7, and more preferably greater than 1.75. 
     It is desirable for the refractive index of the first lens to be less than 1.9. 
     An imaging apparatus according to the present invention is provided with the imaging lens according to the present invention described above. 
     The first imaging lens according to the present invention substantially consists of: 
     a first lens group having a positive refractive power and a second lens group having a positive refractive power in this order from the object side, wherein 
     focusing is performed by moving the entirety of the second lens group along the optical axis; 
     the first lens group comprises a positive first lens which is disposed on the most-object side, a negative second lens which is disposed next to the firts lens on the image side, a negative third lens which is disposed next to the second lens on the image side, a positive fourth lens which is disposed next to the third lens on the image side, and a positive fifth lens which is disposed next to the fourth lens on the image side; and 
     conditional formula (1) below is satisfied when the Abbe numbers of the second lens and the third lens with respect to the d-line are respectively vd 2  and vd 3 :
 
2.0&lt; vd 2/ vd 3  (1).
 
Thereby, the advantageous effects below will be exhibited.
 
     First, disposing a positive lens on the most-object side facilitates correction of distortion. 
     Configuring the second lens and the third lens to be negative lenses facilitates widening the angle of view of the lens system. 
     Configuring the fourth lens and the fifth lens to be positive lenses facilitates correction of spherical aberration. 
     Configuring the value of vd 2 /vd 3  to exceed the lower limit defined by conditional formula (1) facilitates increasing the Abbe number of the second lens, thereby enabling longitudinal chromatic aberration to be easily corrected, or facilitates reducing the Abbe number of the third lens to increase the partial dispersion ratio of the third lens, thereby enabling lateral chromatic aberration to be easily corrected. 
     The second imaging lens of the present invention substantially consists of: 
     a positive first lens group and a positive second lens group in this order from the object side; 
     focusing is performed by moving the entirety of the second lens group along the optical axis; and 
     the most-image-side lens of the first lens group, a lens which is second from the most-image side in the first lens group, and a lens which is third from the most-image side in the first lens group are all meniscus lenses with convex surfaces toward the image side. This facilitates favorable correction of spherical aberration. 
     The imaging apparatus of the present invention equipped with the first imaging lens according to the present invention facilitates correcting distortion, widening the angle of view of the lens system, and correcting spherical aberration; and enables longitudinal chromatic aberration or lateral chromatic aberration to be easily corrected in the same manner as described above. These points enable excellent images to be obtained. 
     The imaging apparatus of the present invention equipped with the second imaging lens according to the present invention facilitates correcting spherical aberration favorably in the same manner as described above. This enables excellent images to be obtained. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view illustrating the lens configuration of an imaging lens according to one embodiment of the present invention. 
         FIG. 2  is a cross-sectional view illustrating the lens configuration of an imaging lens of Example 1 of the present invention. 
         FIG. 3  is a cross-sectional view illustrating the lens configuration of an imaging lens of Example 2 of the present invention. 
         FIG. 4  is a cross-sectional view illustrating the lens configuration of an imaging lens of Example 3 of the present invention. 
         FIG. 5  is a cross-sectional view illustrating the lens configuration of an imaging lens of Example 4 of the present invention. 
         FIG. 6  is a cross-sectional view illustrating the lens configuration of an imaging lens of Example 5 of the present invention. 
         FIG. 7  is a cross-sectional view illustrating the lens configuration of an imaging lens according to Example 6 of the present invention. 
         FIG. 8  is a cross-sectional view illustrating the lens configuration of an imaging lens of Example 7 of the present invention. 
         FIG. 9  illustrates aberration diagrams of the imaging lens of Example 1 described above. 
         FIG. 10  illustrates aberration diagrams of the imaging lens of Example 2 described above. 
         FIG. 11  illustrates aberration diagrams of the imaging lens of Example 3 described above. 
         FIG. 12  illustrates aberration diagrams of the imaging lens of Example 4 described above. 
         FIG. 13  illustrates aberration diagrams of the imaging lens of Example 5 described above. 
         FIG. 14  illustrates aberration diagrams of the imaging lens of Example 6 described above. 
         FIG. 15  illustrates aberration diagrams of the imaging lens of Example 7 described above. 
         FIG. 16  is a schematic configuration of an imaging apparatus according to one embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.  FIG. 1  is a cross-sectional view illustrating the lens configuration of an imaging lens according to one embodiment of the present invention with optical paths. The example shown in  FIG. 1  corresponds to Example 1 to be described later. In  FIG. 1 , the left side is the object side, and the right side is the image side. Further, the state focused on the object at infinity is shown. 
     When this imaging lens is applied to an imaging apparatus, it is preferable for a cover glass, various types of filters, such as an infrared cut filter, a low-pass filter, and the like to be provided between the optical system and the imaging plane Sim according to the configurations of a camera on which the lens is mounted.  FIG. 1  illustrates an example in which a plane parallel optical member PP that presumes such filters and a cover glass is provided between the lens system and an imaging plane Sim. However, the optical member PP is not a constituent element necessary for the imaging lens of the present invention. 
     The imaging lens of the present embodiment consists of a first lens group G 1  having a positive refractive power and a second lens group G 2  having a positive refractive power in this order from the object side along the optical axis Z. Focusing is performed by moving the entirety of the second lens group G 2  along the optical axis Z. 
     The first lens group G 1  consists of a positive first lens L 11 , a negative second lens L 12 , a negative third lens L 13 , a positive fourth lens L 14 , a positive fifth lens L 15 , a negative sixth lens L 16 , a negative seventh lens L 17 , a positive eighth lens L 18 , and a positive ninth lens L 19  in this order from the object side along the optical axis Z. Note that the seventh lens L 17  and the eighth lens L 18  are cemented to each other. 
     The second lens group G 2  consists of a positive lens L 21 , a negative lens L 22 , a positive lens L 23 , a negative lens L 24 , a positive lens L 25 , and a positive lens L 26  in this order from the object side along the optical axis Z. Note that the positive lens L 23  and the negative lens L 24  are cemented to each other. 
     An aperture stop St is disposed between the first lens group G 1  and the second lens group G 2 . In this case, the aperture stop St shown in  FIG. 1  does not necessarily represent the size or shape thereof, but the position thereof on the optical axis Z. Disposing the aperture stop St between the first lens group G 1  and the second lens group G 2  in such a manner facilitates suppression of the diameters of the lenses so that miniaturizatin of the lens system will be facilitated. 
     In the present embodiment, both the first lens group G 1  and the second lens group G 2  which are respectively disposed at the front and the back of the sperture stop St have positive refractive powers. Thereby, cancelling out abrrations which occur at the front and the back of the aperture stop St will be facilitated, and threfore correcting shperical aberration, astigmatism, and comatic aberration will be facilitated. 
     In the present embodiment, when the Abbe numbers of the above second lens L 12  and the third lens L 13  with respect to the-d line are respectively vd 2  and vd 3 , conditional formula (1) below is satisfied:
 
2.0&lt; vd 2/ vd 3  (1).
 
Note that Table 15 to be described later collectively shows values of the conditions, numerical ranges of which are respectively defined by this conditional formula (1) and the other conditional formulas (2) through (17) for each Example. As shown in Table 15, in the present embodiment corresponding to Example 1, the value of vd 2 /vd 3  is specifically 3.43.
 
     In the present embodiment, disposing the first lens L 11  which is a positive lens on the most-object side facilitates correction of distortion. Further, configuring the second lens L 12  and the third lens L 13  to be negative lenses facilitates widening the angle of view of the lens system. Configuring the fourth lens L 14  and the fifth lens L 15  to be positive lenses facilitates correction of spherical aberration. 
     Configuring the value of vd 2 /vd 3  to exceed the lower limit of conditional formula (1) facilitates increasing the Abbe number of the second lens L 12 . This enables longitudinal chromatic aberration to be easily corrected. Alternatively, configuring the value of vd 2 /vd 3  to exceed the lower limit of conditional formula (1) facilitates reducing the Abbe number of the third lens L 13  and increasing the partial dispersion ratio of the third lens L 13 . This enables longitudinal chromatic aberration and lateral chromatic aberration to be easily corrected. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (1), it is preferable for the lower limit of the condition defined by conditional formula (1) to be 2.5, and more preferably 3.5. That is, it is more preferable for conditional formula (1-1) below to be satisfied, and even mover preferable for conditional formula (1-2) below to be satisfied:
 
2.5&lt; vd 2/ vd 3  (1-1)
 
3.0&lt; vd 2/ vd 3  (1-2).
 
     Further, regarding the value of vd 2 /vd 3  described above, it is also preferable for conditional formula (1-3) below to be satisfied:
 
2.0&lt; vd 2/ vd 3&lt;5.0  (1-3).
 
Configuring the upper limit of the value of vd 2 /vd 3  to 5.0 in such a manner facilitates suppression of the cost for the lens material. Further, it is preferable for the upper limit of the value of vd 2 /vd 3  to be 4.0. In this case, the above advantageous effect will become more prominent.
 
     In the present embodiment, configuring all of the ninth lens L 19  which is the most-image-side lens of the first lens group G 1 , the eighth lens L 18  which is the lens that is second from the most-image side in the first lens group G 1 , and the seventh lens L 17  which is the lens that is third from the most-image side in the first lens group G 1  to be meniscus lenses with convex surfaces toward the image side facilitates favorable correction of spherical aberration. 
     In the present embodiment, configuring all of the ninth lens L 19  which is the most-image-side lens of the first lens group G 1 , the eighth lens L 18  which is the lens that is second from the most-image side in the first lens group G 1 , and the seventh lens L 17  which is the lens that is third from the most-image side in the first lens group G 1  to be negative lenses facilitates favorable correction of spherical aberration. 
     In the present embodiment, the positive first lens L 11  is disposed on the most-object side, and two or more negative lenses (particularly, the second lens L 12  and the third lens L 13 ) are disposed adjacent thereto. This facilitates correction of distortion while having a wide angle of view and securing long back focus. 
     Further, disposing the positive fourth lens L 14  and the positive fifth lens L 15  as the fourth lens and the fifth lens, respectively facilitates correction of field curvature and spherical aberration. Further, disposing the negative sixth lens L 16 , the negative seventh lens L 17 , the positive eighth lens L 18 , and the positive ninth lens L 19  as the sixth lens through the ninth lens, respectively facilitates favorable correction of spherical aberration and field curvature as well as longitudinal chromatic aberration and lateral chromatic aberration. 
     In the present embodiment, when the focal length of the first lens group G 1  is FA and the focal length of the second lens group G 2  is FB, conditional formula (2) below is satisfied:
 
1.0&lt; FA/FB&lt; 8.0  (2).
 
Particularly, the value of FA/FB is 4.46 in Example 1 as shown in Table 15.
 
     Configuring the value of FA/FB to be less than the upper limit defined by conditional formula (2) facilitates suppressing an excessive decrease in the power of the first lens group G 1 . This facilitates a reduction of the diameter. Alternatively, configuring the value of FA/FB to be less than the upper limit defined by conditional formula (2) facilitates suppressing an excessive increase in the power of the second lens group G 2 . This facilitates securing back focus. In contrast, configuring the value of FA/FB to be greater than the lower limit defined by conditional formula (2) facilitates suppressing an excessive increase in the positive power of the first lens group G 1 . This makes it easy to widen the angle of view. Alternatively, configuring the value of FA/FB to be greater than the lower limit defined by conditional formula (2) facilitates suppressing an excessive decrease in the power of the second lens group G 2 . This makes it easy to suppress the angles at which the peripheral rays enter the image sensor. 
     Note that in order to further enhance the above advantageous effect obtained by satisfying conditional formula (2), it is preferable for the upper limit of the condition defined by conditional formula (2) to be 7.0, more preferably 6.0, and even more preferably 5.0. Further, in order to further enhance the above advantageous effect, it is preferable for the lower limit of the condition defined by conditional formula (2) to be 1.5, more preferably 2.0, and even more preferably 2.2. That is, the advantageous effect will be enhanced further by satisfying conditional formulas (2-1), (2-2), or (2-3), for example:
 
1.5&lt; FA/FB&lt; 7.0  (2-1)
 
2.0&lt; FA/FB&lt; 6.0  (2-2)
 
2.2&lt; FA/FB&lt; 5.0  (2-3).
 
     In the present embodiment, the first lens group G 1  includes the first lens L 11  which is disposed on the most-object side. When the focal length of the first lens L 11  is f 1  and the focal length of the entire system is f, conditional formula (3) below is satisfied:
 
1&lt; f 1/ f&lt; 6  (3).
 
Particularly, the value of f 1 /f is 3.63 in Example 1 as shown in Table 15.
 
     Configuring the value of f 1 /f to be less than the upper limit defined by conditional formula (3) facilitates correction of distortion. In contrast, configuring the value of f 1 /f to be greater than the lower limit defined by conditional formula (3) facilitates widening the angle of view. Note that the power of the first lens L 11  is not limited to the power in the present embodiment to obtain the above advantageous effect. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (3), it is preferable for the upper limit of the condition defined by conditional formula (3) to be 5.5, more preferably 5.0, and even more preferably 4.5. Further, in order to enhance the above advantageous effect further, it is preferable for the lower limit of the condition defined by conditional formula (3) to be 2, more preferably 2.5, and even more preferably 3. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (3-1), (3-2), or (3-3), for example:
 
2&lt; f 1/ f&lt; 5.5  (3-1)
 
2.5&lt; f 1/ f&lt; 4.5  (3-2)
 
3&lt; f 1/ f&lt; 5  (3-3).
 
     In the present embodiment, the most-image-side lens of the second lens group G 2  is a positive lens L 26 . When the radius of curvature of the object-side surface of the positive lens L 26  which is disposed on the most-image side and the radius of curvature of the image-side surface of the positive lens L 26  are respectively RLF and RLB, conditional formula (4) below is satisfied:
 
0.5&lt;( RLF+RLB )/( RLF−RLB )&lt;3.0  (4).
 
Particularly, the value of (RLF+RLB)/(RLF−RLB) is 1.00 in Example 1 as shown in Table 15.
 
     Configuring the value of (RLF+RLB)/(RLF−RLB) to be less than the upper limit defined by conditional formula (4) facilitates preventing the radii of curvature of both surfaces of the positive lens L 26  (front and back lens surfaces) from excessively approximating each other. This makes it easy to prevent the power of the positive lens L 26  from becoming weak. As the result thereof, suppressing the angles at which the peripheral rays enter the image sensor will be facilitated. In contrast, configuring the value of (RLF+RLB)/(RLF−RLB) to be greater than the lower limit defined by conditional formula (4) facilitates increasing the difference between the radii of curvature of both surfaces of the positive lens L 26 . As the result thereof, correcting astigmatism and comatic aberration will be facilitated. 
     Note that in order to further enhance the above advantageous effect obtained by satisfying conditional formula (4), it is preferable for the upper limit of the condition defined by conditional formula (4) to be 2.5, more preferably 2.0, and even more preferably 1.5. Further, in order to enhance the above advantageous effect further, it is more preferable for the lower limit of the condition defined by conditional formula (4) to be 0.55, and even more preferably 0.6. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (4-1), (4-2), or (4-3), for example:
 
0.5&lt;( RLF+RLB )/( RLF−RLB )&lt;2.5  (4-1)
 
0.55&lt;( RLF+RLB )/( RLF−RLB )&lt;2.0  (4-2)
 
0.6&lt;( RLF+RLB )/( RLF−RLB )&lt;1.5  (4-3).
 
     In the present embodiment, the lens which is second from the most-image side in the second lens group G 2  is the positive lens L 25 . When the radius of curvature of the object-side surface of the positive lens L 25  which is second from the most-image side and the radius of curvature of the image-side surface of the positive lens L 25  are respectively RL 2 F and RL 2 B; conditional formula (5) below is satisfied:
 
0.3&lt;( RL 2 F+RL 2 B )/( RL 2 F−RL 2 B )&lt;3.0  (5).
 
Particularly, the value of (RL 2 F+RL 2 B)/(RL 2 F−RL 2 B) is 1.67 in Example 1 as shown in Table 15.
 
     Configuring the value of (RL 2 F+RL 2 B)/(RL 2 F−RL 2 B) to be less than the upper limit defined by conditional formula (5) facilitates preventing the radii of curvature of both surfaces of the positive lens L 25  (front and back lens surfaces) from excessively approximating each other. This makes it easy to prevent the power of the positive lens L 25  from becoming weak. As the result thereof, suppressing the angles at which the peripheral rays enter the image sensor will be facilitated. In contrast, configuring the value of (RL 2 F+RL 2 B)/(RL 2 F−RL 2 B) to be greater than the lower limit defined by conditional formula (5) facilitates increasing the difference between the radii of curvature of both surfaces of the positive lens L 25 . As the result thereof, correcting astigmatism and comatic aberration will be facilitated. 
     Note that in order to further enhance the above advantageous effect obtained by satisfying conditional formula (5), it is preferable for the upper limit of the condition defined by conditional formula (5) to be 2.5, more preferably 2.0, and even more preferably 1.8. Further, in order to enhance the above advantageous effect further, it is more preferable for the lower limit of the condition defined by conditional formula (5) to be 0.8, even more preferably 1.2, and still more preferably 1.4. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (5-1), (5-2), or (5-3), for example:
 
0.8&lt;( RL 2 F+RL 2 B )/( RL 2 F−RL 2 B )&lt;2.5  (5-1)
 
1.2&lt;( RL 2 F+RL 2 B )/( RL 2 F−RL 2 B )&lt;2.0  (5-2)
 
1.4&lt;( RL 2 F+RL 2 B )/( RL 2 F−RL 2 B )&lt;1.8  (5-3).
 
     In the present embodiment, both the positive lens L 26  which is the most-image-side lens of the second lens group G 2  and the positive lens L 25  which is the lens that is second from the most-image side are lenses with convex surfaces toward the image. This facilitates correction of astigmatism and comatic aberration. 
     In the present embodiment, the first lens group G 1  includes the first lens L 11 , the second lens L 12 , the third lens L 13 , and the fourth lens L 14  in this order from the object side. When the combined focal length of the first lens L 11  through the fourth lens L 14  is f 1234  and the focal length of the entire system is f, conditional formula (6) below is satisfied:
 
−3.0&lt; f 1234/ f&lt;− 0.5  (6).
 
Particularly, the value of f 1234 /f is −1.42 in Example 1 as shown in Table 15.
 
     Configuring the value of f 1234 /f to be less than the upper limit defined by conditional formula (6) facilitates suppressing an excessive decrease of the combined focal length of the first lens L 11  through the fourth lens L 14  as a negative value. This facilitates correction of astigmatism. In contrast, configuring the value of f 1234 /f to be greater than the lower limit defined by conditional formula (6) facilitates suppressing an excessive increase of the combined focal length of the first lens L 11  through the fourth lens L 14  as a negative value. This facilitates widening the angle of view. Note that the lens power arrangement of the first lens L 11  through the fourth lens L 14  is not limited to the power arrangement in the present embodiment to obtain the advantageous effect described above. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (6), it is preferable for the upper limit of the condition defined by conditional formula (6) to be −0.7, more preferably −0.9, and even more preferably −1.2. Further, in order to enhance the above advantageous effect further, it is more preferable for the lower limit of the condition defined by conditional formula (6) to be −2.5, even more preferably −2.0, and still more preferably −1.9. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (6-1), (6-2), or (6-3), for example:
 
−2.5&lt; f 1234/ f&lt;− 0.7  (6-1)
 
−2.0&lt; f 1234/ f&lt;− 0.9  (6-2)
 
−1.9&lt; f 1234/ f&lt;− 1.2  (6-3).
 
     In the present embodiment, the first lens group G 1  includes the first lens L 11 , the second lens L 12 , and the third lens L 13 . When the combined focal length of the first lens L 11  through the third lens L 13  is f 123  and the focal length of the entire system is f, conditional formula (7) below is satisfied:
 
−3.0&lt; f 123/ f&lt;− 0.2  (7).
 
Particularly, the value of f 123 /f is −0.85 in Example 1 as shown in Table 15.
 
     Configuring the value of f 123 /f to be less than the upper limit defined by conditional formula (7) facilitates suppressing an excessive decrease of the combined focal length of the first lens L 11  through the third lens L 13  as a negative value. This facilitates correction of field curvature. In contrast, configuring the value of f 123 /f to be greater than the lower limit defined by conditional formula (7) facilitates suppressing an excessive increase of the combined focal length of the first lens L 11  through the third lens L 13  as a negative value. This facilitates widening the angle of view. Note that the lens power arrangement of the first lens L 11  through the third lens L 13  is not limited to the power arrangement in the present embodiment to obtain the advantageous effect described above. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (7), it is preferable for the upper limit of the condition defined by conditional formula (7) to be −0.4, more preferably −0.6, and even more preferably −0.7. Further, in order to enhance the above advantageous effect further, it is more preferable for the lower limit of the condition defined by conditional formula (7) to be −2.5, even more preferably −2.0, and still more preferably −1.5. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (7-1), (7-2), or (7-3), for example:
 
−2.5&lt; f 123/ f&lt;− 0.4  (7−1)
 
−2.0&lt; f 123/ f&lt;− 0.5  (7−2)
 
−1.5&lt; f 123/ f&lt;− 0.7  (7-3).
 
     In the present embodiment, the first lens L 11  which is the most-object-side lens of the first lens group G 1  is a biconvex lens. This facilitates correction of distortion. 
     In the present embodiment, the first lens group G 1  includes the first lens L 11 , the second lens L 12 , the third lens L 13 , the fourth lens L 14 , and the fifth lens L 15  in this order from the object side, and both of the Abbe numbers vd 4  and vd 5  of the fourth lens L 14  and the fifth lens L 15  with respect to the d-line are less than or equal to 45. Particularly, both of the values of the Abbe numbers vd 4  and vd 5  are 31.32 in Example 1 as shown in Table 1 to be described later. Configuring both of the Abbe numbers vd 4  and vd 5  to be less than or equal to 45 in such a manner facilitates correction of lateral chromatic aberration. Note that the lens power arrangement of the first lens L 11  through the fifth lens L 15  is not limited to the power arrangement in the present embodiment to obtain the advantageous effect described above. 
     In the present embodiment, when the focal length of the first lens group G 1  is FA and the focal length of the entire system is f, conditional formula (8) below is satisfied:
 
2&lt; FA/f&lt; 12.0  (8).
 
Particularly, the value of FA/f is 7.69 in Example 1 as shown in Table 15.
 
     Configuring the value of FA/f to be less than the upper limit defined by conditional formula (8) facilitates suppressing an excessive decrease in the power of the first lens group G 1 . This makes it easy to miniaturize the system. In contrast, configuring the value of FA/f to be greater than the lower limit defined by conditional formula (8) facilitates suppressing an excessive increase in the power of the first lens group G 1 . As the result thereof, widening the angle of view will be facilitated or correcting field curvature will be facilitated. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (8), it is preferable for the upper limit of the condition defined by conditional formula (8) to be 10.0, more preferably 9.0, and even more preferably 8.0. Further, in order to enhance the above advantageous effect obtained by satisfying conditional formula (8) further, it is more preferable for the lower limit of the condition defined by conditional formula (8) to be 3.0, even more preferably 4.0, and still more preferably 5.0. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (8-1), (8-2), or (8-3), for example:
 
3&lt; FA/f&lt; 10.0  (8-1)
 
4&lt; FA/f&lt; 9.0  (8-2)
 
5&lt; FA/f&lt; 8.0  (8-3).
 
     In the present embodiment, when the focal length of the second lens group G 2  is FB and the focal length of the entire system is f, conditional formula (9) below is satisfied:
 
0.5&lt; FB/f&lt; 3.0  (9).
 
Particularly, the value of FB/f is 1.73 in Example 1 as shown in Table 15.
 
     Configuring the value of FB/f to be less than the upper limit defined by conditional formula (9) facilitates suppressing an excessive decrease in the power of the second lens group G 2 . This facilitates suppressing the angles at which the peripheral rays enter the image sensor. In contrast, configuring the value of FB/f to be greater than the lower limit defined by conditional formula (9) facilitates suppressing an excessive increase in the power of the second lens group G 2 . This facilitates making the back focus long and correcting field curvature. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (9), it is preferable for the upper limit of the condition defined by conditional formula (9) to be 2.8, more preferably 2.3, and even more preferably 2.1. Further, in order to enhance the above advantageous effect further, it is more preferable for the lower limit of the condition defined by conditional formula (9) to be 0.8, even more preferably 1.0, and still more preferably 1.4. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (9-1), (9-2), or (9-3), for example:
 
0.8&lt; FB/f&lt; 2.8  (9-1)
 
1.0&lt; FB/f&lt; 2.3  (9-2)
 
1.4&lt; FB/f&lt; 2.1  (9-3).
 
     In the present embodiment, the first lens group G 1  includes the first lens L 11 , the second lens L 12 , the third lens L 13 , and the fourth lens L 14  in this order from the object side. When the radius of curvature of the object-side surface of the fourth lens L 14  and the radius of curvature of the image-side surface of the fourth lens L 14  are respectively R 7  and R 8 , conditional formula (10) below is satisfied:
 
1.5&lt;( R 7+ R 8)/( R 7− R 8)&lt;5.0  (10).
 
Particularly, the value of (R 7 +R 8 )/(R 7 −R 8 ) is 3.78 in Example 1 as shown in Table 15.
 
     Configuring the value of (R 7 +R 8 )/(R 7 −R 8 ) to be less than the upper limit defined by conditional formula (10) facilitates preventing the radii of curvature of the front and back surfaces of the fourth lens L 14  from excessively approximating each other. This makes it easy to correct spherical aberration. In contrast, configuring the value of (R 7 +R 8 )/(R 7 −R 8 ) to be greater than the lower limit defined by conditional formula (10) facilitates increasing the difference between the radii of curvature of the front and back surfaces of the fourth lens L 14 . This makes it easy to correct astigmatism. Note that the lens power arrangement of the first lens L 11  through the fourth lens L 14  is not limited to the power arrangement in the present embodiment to obtain the advantageous effect described above. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (10), it is preferable for the upper limit of the condition defined by conditional formula (10) to be 4.8, more preferably 4.5, and even more preferably 4.0. Further, in order to enhance the above advantageous effect further, it is more preferable for the lower limit of the condition defined by conditional formula (10) to be 2.0, even more preferably 2.6, and still more preferably 2.8. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (10-1), (10-2), or (10-3), for example:
 
2.0&lt;( R 7+ R 8)/( R 7− R 8)&lt;4.8  (10-1)
 
2.6&lt;( R 7+ R 8)/( R 7− R 8)&lt;4.5  (10-2)
 
2.8&lt;( R 7+ R 8)/( R 7− R 8)&lt;4.0  (10-3).
 
     In the present embodiment, the first lens group G 1  includes the first lens L 11 , the second lens L 12 , the third lens L 13 , and the fourth lens L 14  in this order from the object side. When the distance between the third lens L 13  and the fourth lens L 14  is D 6  and the focal length of the entire system is f, conditional formula (11) below is satisfied:
 
0.1&lt; D 6/ f&lt; 1.5  (11).
 
     Note that the distance D 6  is the distance between surfaces which are the image-side surface of the third lens L 13  and the object-side surface of the fourth lens L 14 . Particularly, the value of D 6 /f is 0.38 in Example 1 as shown in Table 15. 
     Configuring the value of D 6 /f to be less than the upper limit defined by conditional formula (11) facilitates miniaturization of the lens system. In contrast, configuring the value of D 6 /f to be greater than the lower limit defined by conditional formula (11) facilitates securing a long back focus. Note that the lens power arrangement of the first lens L 11  through the fourth lens L 14  is not limited to the power arrangement in the present embodiment to obtain the advantageous effect described above. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (11), it is preferable for the upper limit of the condition defined by conditional formula (11) to be 1.3, more preferably 1.0, even more preferably 0.8, and still more preferably 0.5. Further, in order to enhance the above advantageous effect further, it is more preferable for the lower limit of the condition defined by conditional formula (11) to be 0.15, even more preferably 0.2, and still more preferably 0.22. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (11-1), (11-2), or (11-3), for example:
 
0.15&lt; D 6/ f&lt; 1.3  (11-1)
 
0.2&lt; D 6/ f&lt; 1.0  (11-2)
 
0.22&lt; D 6/ f&lt; 0.8  (11-3).
 
     In the present embodiment, the first lens group G 1  includes the first lens L 11 , the second lens L 12 , and the third lens L 13  in this order from the object side. When the distance between the second lens L 12  and the third lens L 13  is D 4  and the focal length of the entire system is f, conditional formula (12) below is satisfied:
 
0.1&lt; D 4/ f&lt; 1.5  (12).
 
Note that the distance D 4  is the distance between surfaces which are the image-side surface of the second lens L 12  and the object-side surface of the third lens L 13 . Particularly, the value of D 4 /f is 0.34 in Example 1 as shown in Table 15.
 
     Configuring the value of D 4 /f to be less than the upper limit defined by conditional formula (12) facilitates preventing the distance between the second lens L 12  and the third lens L 13  from excessively widening. This makes it easy to reduce the diameters of these lenses. In contrast, configuring the value of D 4 /f to be greater than the lower limit defined by conditional formula (12) widens the distance between the second lens L 12  and the third lens L 13  so that separation of the central rays and the peripheral rays in these lenses will be facilitated. As the result thereof, both widening the angle of view and correcting distortion will be facilitated. Note that the lens power arrangement of the first lens L 11  through the third lens L 13  is not limited to the power arrangement in the present embodiment to obtain the advantageous effect described above. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (12), it is preferable for the upper limit of the condition defined by conditional formula (12) to be 1.2, more preferably 1.0, even more preferably 0.7, and still more preferably 0.5. Further, in order to enhance the above advantageous effect further, it is more preferable for the lower limit of the condition defined by conditional formula (12) to be 0.15, even more preferably 0.2, and still more preferably 0.21. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (12-1), (12-2), or (12-3), for example:
 
0.15&lt; D 4/ f&lt; 1.2  (12-1)
 
0.2&lt; D 4/ f&lt; 1.0  (12-2)
 
0.21&lt; D 4/ f&lt; 0.7  (12-3).
 
     In the present embodiment, the first lens group G 1  includes the first lens L 11  and the second lens L 12  in this order from the object side. When the focal length of the first lens L 11  is f 1  and the focal length of the second lens L 12  is f 2 , conditional formula (13) below is satisfied:
 
−3.0&lt; f 1/ f 2&lt;−0.05  (13).
 
Particularly, the value of f 1 /f 2  is −0.35 in Example 1 as shown in Table 15.
 
     Configuring the value of f 1 /f 2  to be less than the upper limit defined by conditional formula (13) facilitates preventing the power of the first lens L 11  from excessively increasing or facilitates preventing the power of the second lens L 12  from excessively decreasing. This makes it easy to widen the angle of view. In contrast, configuring the value of f 1 /f 2  to be greater than the lower limit defined by conditional formula (13) facilitates preventing the power of the first lens L 11  from excessively decreasing. This makes it easy to correct distortion. Note that the lens power arrangement of the first lens L 11  and the second lens L 12  is not limited to the power arrangement in the present embodiment to obtain the advantageous effect described above. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (13), it is more preferable for the upper limit of the condition defined by conditional formula (13) to be −0.2, and even more preferably −0.25. Further, in order to enhance the above advantageous effect further, it is more preferable for the lower limit of the condition defined by conditional formula (13) to be −1.8, even more preferably −1.5, and still more preferably −1.0. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (13-1), (13-2), or (13-3), for example:
 
−1.8&lt; f 1/ f 2&lt;−0.2  (13−1)
 
−1.5&lt; f 1/ f 2&lt;−0.25  (13−2)
 
−1.0&lt; f 1/ f 2&lt;−0.25  (13-3).
 
     In the present embodiment, the first lens group G 1  includes the first lens L 11  which is disposed on the most-object side. When the distance between the object-side surface of the first lens L 11  and the imaging plane (the back focus corresponds to the air converted length) is L and the focal length of the entire system is f, conditional formula (14) below is satisfied:
 
2.0&lt; L/f&lt; 8.0  (14).
 
Particularly, the value of L/f is 5.16 in Example 1 as shown in Table 15.
 
     Configuring the value of L/f to be less than the upper limit defined by conditional formula (14) facilitates miniaturization of the lens system. In contrast, configuring the value of L/f to be greater than the lower limit defined by conditional formula (14) facilitates widening the angle of view. Note that the power of the first lens L 11  is not limited to the power in the present embodiment to obtain the advantageous effect described above. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (14), it is more preferable for the upper limit of the condition defined by conditional formula (14) to be 7.5, even more preferably 7.0, and still more preferably 6.0. Further, in order to enhance the above advantageous effect further, it is preferable for the lower limit of the condition defined by conditional formula (14) to be 2.5, more preferably 3.0, even more preferably 3.5, and still more preferable 4.0. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (14-1), (14-2), or (14-3), for example:
 
2.5&lt; L/f&lt; 7.5  (14-1)
 
3.0&lt; L/f&lt; 7.0  (14-2)
 
3.5&lt; L/f&lt; 6.0  (14-3).
 
     In the present embodiment, when the back focus (air converted length) is Bf and the focal length of the entire system is f, conditional formula (15) below is satisfied:
 
0.3&lt; Bf/f&lt; 3.0  (15).
 
Particularly, the value of Bf/f is 1.21 in Example 1 as shown in Table 15.
 
     Configuring the value of Bf/f to be less than the upper limit defined by conditional formula (15) facilitates preventing the back focus from becoming too long. This makes it easy to miniaturize the lens system. In contrast, configuring the value of Bf/f to greater than the lower limit defined by conditional formula (15) facilitates preventing the back focus from becoming too short. Thereby, disposing various types of filters and a cover glass between the image sensor and the lens system will be facilitated, and it will be possible to apply the imaging lens of the present embodiment for use in a wider variety of imaging apparatuses. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (15), it is more preferable for the upper limit of the condition defined by conditional formula (15) to be 2.5, even more preferably 2.0, and still more preferably 1.8. Further, in order to enhance the above advantageous effect further, it is preferable for the lower limit of the condition defined by conditional formula (15) to be 0.5, more preferably 0.8, and even more preferably 1.0. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (15-1), (15-2), or (15-3), for example:
 
0.5&lt; Bf/f&lt; 2.5  (15-1)
 
0.8&lt; Bf/f&lt; 2.0  (15-2)
 
1.0&lt; Bf/f&lt; 1.8  (15-3).
 
     In the present embodiment, the first lens group G 1  includes the first lens L 11  and the second lens L 12  in this order from the object side. When the radius of curvature of the object-side surface of the first lens L 11  is R 1  and the radius of curvature of the image-side surface of the second lens L 12  is R 2 , conditional formula (16) below is satisfied:
 
−5.0&lt;( R 1+ R 2)/( R 1− R 2)&lt;−0.2  (16)
 
Particularly, the value of (R 1 +R 2 )/(R 1 −R 2 ) is −0.95 in Example 1 as shown in Table 15.
 
     Configuring the value of (R 1 +R 2 )/(R 1 −R 2 ) to be less than the upper limit defined by conditional formula (16) facilitates increasing the radius of curvature of the image-side surface of the second lens L 12 . This makes it easy to correct comatic aberration and astigmatism. In contrast, configuring the value of (R 1 +R 2 )/(R 1 −R 2 ) to be greater than the lower limit defined by conditional formula (6) facilitates increasing the power of the first lens L 11 . This makes it easy to correct distortion. Note that the power arrangement of the first lens L 11  and the second lens L 12  is not limited to the power arrangement in the present embodiment to obtain the advantageous effect described above. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (16), it is more preferable for the upper limit of the condition defined by conditional formula (16) to be −0.3, even more preferably −0.4, and still more preferably −0.6. Further, in order to enhance the above advantageous effect further, it is preferable for the lower limit of the condition defined by conditional formula (16) to be −4.0, more preferably −3.0, and even more preferably −2.0. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (16-1), (16-2), or (16-3), for example:
 
−4.0&lt;( R 1+ R 2)/( R 1− R 2)&lt;−0.3  (16-1)
 
−3.0&lt;( R 1+ R 2)/( R 1− R 2)&lt;−0.4  (16-2)
 
−2.0&lt;( R 1+ R 2)/( R 1− R 2)&lt;−0.6  (16-3).
 
     In the present embodiment, the first lens group G 1  includes the first lens L 11 , the second lens L 12 , the third lens L 13 , the fourth lens L 14 , and the fifth lens L 15  in this order from the object side. When the radius of curvature of the object-side surface of the fifth lens L 15  and the radius of curvature of the image-side surface of the fifth lens L 15  are respectively R 9  and R 10 , conditional formula (17) below is satisfied:
 
−5.0&lt;( R 9+ R 10)/( R 9− R 10)&lt;−0.2  (17).
 
Particularly, the value of (R 9 +R 10 )/(R 9 −R 10 ) is −1.00 in Example 1 as shown in Table 15.
 
     Configuring the fifth lens L 15  to be a positive lens and the value of (R 9 +R 10 )/(R 9 −R 10 ) to be less than the upper limit defined by conditional formula (17) facilitates having the radius of curvature of the object-side surface of the fifth lens L 15  smaller than the radius of curvature of the image-side surface thereof. This further makes it easy to correct astigmatism. In contrast, configuring the fifth lens  115  to be a positive lens and the value of (R 9 +R 10 )/(R 9 −R 10 ) to be greater than the lower limit defined by conditional formula (17) facilitates increasing the difference between the radius of curvature of the object-side surface of the fifth lens L 15  and the radius of curvature of the image-side surface thereof. Accordingly, it will be easy to increase the power of the fifth lens L 15 , thereby facilitating correction of spherical aberration. Note that the lens power arrangement of the first lens L 11  through the fifth lens L 15  is not limited to the power arrangement in the present embodiment to obtain the advantageous effect described above. 
     In order to further enhance the above advantageous effect obtained by satisfying conditional formula (17), it is more preferable for the upper limit of the condition defined by conditional formula (17) to be −0.3, even more preferably −0.4, and still more preferably −0.5. Further, in order to enhance the above advantageous effect further, it is preferable for the lower limit of the condition defined by conditional formula (17) to be −4.0, more preferably −3.0, and even more preferably −2.0. That is, the above advantageous effect will be enhanced further by satisfying conditional formulas (17-1), (17-2), or (17-3), for example:
 
−4.0&lt;( R 9+ R 10)/( R 9− R 10)&lt;−0.3  (17-1)
 
−3.0&lt;( R 9+ R 10)/( R 9− R 10)&lt;−0.4  (17-2)
 
−2.0&lt;( R 9+ R 10)/( R 9− R 10)&lt;−0.5  (17-3).
 
     Next, specific Examples of the imaging lens of the present invention will be described. 
     Example 1 
     A cross-sectional view illustrating the lens configuration of an imaging lens of Example 1 is shown in  FIG. 2 . Referring to  FIG. 2 , a schematic configuration of the imaging lens of Example 1 will be described. This imaging lens consists of a first lens group G 1  having a positive refractive power and a second lens group G 2  having a positive refractive power in this order from the object side along the optical axis Z. Focusing is performed by moving the entirety of the second lens group G 2  along the optical axis Z. 
     The first lens group G 1  consists of a positive first lens L 11 , a negative second lens L 12 , a negative third lens L 13 , a positive fourth lens L 14 , a positive fifth lens L 15 , a negative sixth lens L 16 , a negative seventh lens L 17 , a positive eighth lens L 18 , and a positive ninth lens L 19  in this order from the object side along the optical axis Z. Note that the seventh lens L 17  and the eighth lens L 18  are cemented to each other. 
     Meanwhile, the second lens group G 2  consists of a positive lens L 21 , a negative lens L 22 , a positive lens L 23 , a negative lens L 24 , a positive lens L 25 , and a positive lens L 26  in this order from the object side along the optical axis Z. Note that the positive lens L 23  and the negative lens L 24  are cemented to each other. 
     An aperture stop St is disposed between the first lens group G 1  and the second lens group G 2 . In this case, the aperture stop St shown in  FIG. 2  does not necessarily represent the size or shape thereof, but the position thereof on the optical axis Z.  FIG. 2  illustrates an example in which a plane parallel optical member PP that presumes various types of filters, a cover glass, and the like is disposed between the second lens group G 2  and the imaging plane Sim. 
     The first lens group G 1  includes one cemented lens formed by cementing the seventh lens L 17  and the eighth lens L 18  together. This cemented lens is formed by cementing the eighth lens L 18  which is one positive lens and the seventh lens L 17  which is one negative lens together. Configuring the first lens group G 1  to include such a cemented lens enables longitudinal chromatic aberration and lateral chromatic aberration to be corrected favorably. 
     Further, each of a lens which is first from the most-image side of the first lens group G 1 , i.e., the ninth lens L 19 , a lens which is second from the most-image side of the first lens group G 1 , i.e., the eighth lens L 18 , and a lens which is third from the most-image side of the first lens group G 1 , i.e., the seventh lens L 17  is a meniscus lens. This facilitates correction of spherical aberration, astigmatism, and comatic aberration. 
     Further, each of a lens which is first from the most-image side of the first lens group G 1 , i.e., the ninth lens L 19 , a lens which is second from the most-image side of the first lens group G 1 , i.e., the eighth lens L 18 , and a lens which is third from the most-image side of the first lens group G 1 , i.e., the seventh lens L 17  is a lens with a convex surface toward the image side. This facilitates correction of spherical aberration and astigmatism. 
     The most-image-side lens of the first lens group G 1 , i.e., the ninth lens L 19  is a positive meniscus lens. This facilitates favorable correction of astigmatism and comatic aberration. Further, the above positive meniscus lens is a positive meniscus lens with a convex surface toward the image side, in particular. This facilitates correction of astigmatism and comatic aberration. 
     The first lens L 11  is a biconvex lens. This facilitates increasing the power of the first lens L 11 , thereby making it easy to correct distortion. 
     Further, the first lens L 11  is configured to have the absolute value of the radius of curvature of the object-side surface thereof which is smaller than the absolute value of the radius of curvature of the image-side surface thereof (refer to Table 1 to be described later). This facilitates correction of astigmatism and distortion. 
     Further, the second lens L 12  is a concave meniscus lens with a convex surface toward the object side. This facilitates correction of distortion. 
     The third lens L 13  is a biconcave lens. This facilitates widening the angle of view. 
     Further, the third lens L 13  is configured to have the absolute value of the radius of curvature of the object-side surface thereof which is greater than the absolute value of the radius of curvature of the image-side surface thereof (refer to Table 1 to be described later). This facilitates correction of field curvature. 
     Further, configuring the fourth lens L 14  to be a positive lens facilitates correction of spherical aberration and astigmatism. 
     In addition, the fourth lens L 14  is a meniscus lens with a convex surface toward the image side. This also facilitates correction of spherical aberration and astigmatism. 
     Further, configuring the fifth lens L 15  to be a positive lens facilitates correction of spherical aberration. 
     The fifth lens L 15  is configured to be a lens with a convex surface toward the object side. This facilitates correction of spherical aberration and astigmatism. 
     Further, the fifth lens L 15  is configured to be a planoconvex lens with a convex surface toward the object side, in particular. This facilitates correction of spherical aberration and astigmatism. 
     Configuring the sixth lens L 16  to be a negative lens enables spherical aberrations and astigmatism as well as longitudinal chromatic aberration and lateral chromatic aberration to be corrected favorably. 
     The sixth lens L 16  is configured to be a biconcave lens, in particular. This enables spherical aberrations and astigmatism as well as longitudinal chromatic aberration and lateral chromatic aberration to be corrected favorably. 
     Further, the sixth lens L 16  is configured to have the absolute value of the radius of curvature of the object-side surface thereof which is greater than the absolute value of the radius of curvature of the image-side surface thereof (refer to Table 1 to be described later). This facilitates correction of spherical aberration and astigmatism. 
     Further, the seventh lens L 17  is a meniscus lens with a concave surface toward the object side. This facilitates correction of spherical aberration and astigmatism. 
     Configuring the seventh lens L 17  to be a negative lens facilitates correction of spherical aberration and astigmatism. 
     Further, the eighth lens L 18  is a meniscus lens with a concave surface toward the object side. This facilitates correction of spherical aberration and astigmatism. 
     Configuring the eighth lens L 18  to be a positive lens facilitates correction of spherical aberration and astigmatism. 
     The seventh lens L 17  and the eighth lens L 18  are cemented to each other. This enables longitudinal chromatic aberration and lateral chromatic aberration to be corrected favorably. 
     The ninth lens L 19  is configured to be a meniscus lens with a concave surface toward the object side. This facilitates correction of spherical aberration and astigmatism. 
     Configuring the ninth lens L 19  to be a positive lens facilitates correction of spherical aberration and astigmatism. 
     Meanwhile, the second lens group G 2  includes a cemented lens formed by cementing the positive lens L 23  and the negative lens L 24  to each other. Configuring the second lens group G 2  to include at least one such a cemented lens enables longitudinal chromatic aberration and lateral chromatic aberration to be corrected favorably. 
     The second lens group G 2  is configured to include two negative lenses L 22  and L 24 . Configuring the second lens group G 2  to include at least two or more such negative lenses facilitates correction of longitudinal chromatic aberration and lateral chromatic aberration. 
     The most-object-side lens of the second lens group G 2  is a positive lens L 21 . This facilitates correction of astigmatism. 
     The above positive lens L 21  which is the most-object-side lens of the second lens group G 2  is particularly a biconvex lens. This facilitates correction of astigmatism. 
     Further, the positive lens L 21  which is the most-object-side lens of the second lens group G 2  is configured to have the absolute value of the radius of curvature of the object-side surface which is smaller than the absolute value of the radius of curvature of the image-side surface (refer to Table 1 to be described later). This facilitates correction of astigmatism. 
     A lens which is second from the object side of the second lens group G 2  is a negative lens L 22 . This facilitates correction of spherical aberration and astigmatism as well as longitudinal chromatic aberration and lateral chromatic aberration. 
     A lens which is third from the object side of the second lens group G 2  is a positive lens L 23 . This facilitates correction of spherical aberration and astigmatism. 
     A lens which is fourth from the object side of the second lens group G 2  is a negative lens L 24 . This facilitates correction of spherical aberration and astigmatism as well as longitudinal chromatic aberration and lateral chromatic aberration. 
     The positive lens L 23  which is a lens that is third from the object side of the second lens group G 2  and the negative lens L 24  which is a lens that is fourth from the object side of the second lens group G 2  are cemented to each other. This facilitates correction of longitudinal chromatic aberration and lateral chromatic aberration. 
     A lens which is fifth from the object side of the second lens group G 2  is a positive lens L 25 . This facilitates suppression of the angles at which the peripheral rays enter the image sensor. 
     A lens which is sixth from the object side of the second lens group G 2  is a positive lens L 26 . This facilitates suppression of the angles at which the peripheral rays enter the image sensor. 
     The most-image-side lens of the second lens group G 2  is the positive lens L 26 . Configuring the most-image-side lens of the second lens group G 2  to be a positive lens in such a manner facilitates suppression of the angles at which the peripheral rays enter the image sensor. 
     The lens which is second from the most-image side of the second lens group G 2  is the positive lens L 25 . Configuring the lens which is second from the most-image side of the second lens group G 2  to be a positive lens in such a manner facilitates suppression of the angles at which the peripheral rays enter the image sensor. 
     Further, each of the positive lens L 26  which is the most-image-side lens of the second lens group G 2  and the positive lens L 25  which is the lens that is second from the most-image side in the second lens group G 2  is a lens with a convex surface toward the image side, in particular. This facilitates suppression of the angles at which the peripheral rays enter the image sensor. 
     Further, the object-side surface of the first lens L 11  which is the most-object-side lens of the first lens group G 1 , the image-side surface of the ninth lens L 19  which is the most-image-side lens of the first lens group G 1 , the object-side surface of the positive lens L 21  which is the most-object-side lens of the second lens group G 2 , and the image-side surface of the positive lens L 26  which is the most-image-side lens of the second lens group G 2  are all convex surfaces. This facilitates correction of astigmatism, comatic aberration, and distortion. 
     Table 1 shows basic lens data of the imaging lens of Example 1. The column Si shows the i-th (i=1, 2, 3, . . . ) surface number, the value of i sequentially increasing from the object-side surface of the constituent element at the most object side, which is designated as 1, toward the image side. The column Ri shows the radii of curvature of the i-th surface, and the column Di shows the distances between i-th surfaces and (i+1)th surfaces along the optical axis Z. Further, the column Ndj shows the refractive indices of j-th (j=1, 2, 3, . . . ) optical elements with respect to the d-line (wavelength: 587.6 nm), the value of j sequentially increasing from the constituent element at the most object side, which is designated as 1, toward the image side. The column vdj shows the Abbe numbers of j-th optical elements with respect to the d-line (wavelength: 587.6 nm). The column of θg,Fj shows the partial dispersion ratios of j-th (j=1, 2, 3, . . . ) optical elements with respec to the g-line (wavelength: 435.8 nm) and the F-line (wavelength: 486.1=). Names of the materials are written in the column on the right side thereof. 
     Note that the lens data also shows the aperture stop St and the optical member PP. Further, the column of the surface number of a surface corresponding to the aperture stop St indicates a surface number (Stop). The sign of the radius of curvature is positive in the case that a surface shape is convex on the object side, and negative in the case that the surface shape is convex on the image side. The value in the lowest column of Di represents the distance between the image-side surface of the optical member PP and the imaging plane Sim. Further, Table 1 shows the numerical values which are rounded to a predetermined number of digits as appropriate. 
     As specs with respect to the d-line of the imaging lens of Example 1, Table 2 shows values of the focal length f′ of the entire system, the back focus (air converted length) Bf′, the F-number Fno., and the total angle of view 2ω. Degrees are used as the unit of the total angle of view 2ω. The values of the focal length f′ of the entire system and the back focus Bf′ are normalized such that the former becomes 1.00. Accordingly, no units are employed for the focal length f′ of the entire system and the back focus Bf′. Note that the values of the radius of curvature Ri and the distance between surfaces Di are also normalized in the same manner as described above. 
     The manner in which Table 1 is shown as described above is the same for Tables 3, 5, 7, 9, 11, and 13 to be described later. Further, the manner in which Table 2 is shown is the same for Tables 4, 6, 8, 10, 12, and 14 to be described later. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Example 1/Lens Data 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Di 
                   
                   
                 θ g, F j 
                   
               
               
                 Si 
                 Ri 
                 Distances 
                 Ndj 
                 ν dj 
                 Partial 
               
               
                 Surface 
                 Radii of 
                 Between 
                 Refractive 
                 Abbe 
                 Dispersion 
                 Names of 
               
               
                 Numbers 
                 Curvature 
                 Surfaces 
                 Indices 
                 Numbers 
                 Ratios 
                 Materials 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 1 
                 3.11242 
                 0.1817 
                 1.83481 
                 42.73 
                 0.56486 
                 S-LAH55V 
               
               
                 2 
                 −110.65537 
                 0.0069 
               
               
                 3 
                 1.55675 
                 0.0759 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 4 
                 0.68679 
                 0.3437 
               
               
                 5 
                 −2.18192 
                 0.0517 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 6 
                 1.18063 
                 0.3789 
               
               
                 7 
                 −2.54861 
                 0.2079 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 8 
                 −1.48287 
                 0.0334 
               
               
                 9 
                 1.34965 
                 0.1655 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 10 
                 ∞ 
                 0.2248 
               
               
                 11 
                 −12.28776 
                 0.0517 
                 1.57501 
                 41.50 
                 0.57672 
                 S-TIL27 
               
               
                 12 
                 1.87326 
                 0.1293 
               
               
                 13 
                 −1.30818 
                 0.0521 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 14 
                 −3.45566 
                 0.1034 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 15 
                 −1.82957 
                 0.0069 
               
               
                 16 
                 −6.02933 
                 0.1189 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 17 
                 −1.60481 
                 0.0793 
               
               
                 18(Stop) 
                 ∞ 
                 0.2299 
               
               
                 19 
                 3.35631 
                 0.0886 
                 1.80400 
                 46.57 
                 0.55724 
                 S-LAH65 
               
               
                 20 
                 −7.29650 
                 0.2045 
               
               
                 21 
                 9.60747 
                 0.0414 
                 1.62588 
                 35.70 
                 0.58935 
                 S-TIM1 
               
               
                 22 
                 1.10598 
                 0.0500 
               
               
                 23 
                 2.60843 
                 0.3175 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 24 
                 −0.61801 
                 0.2045 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 25 
                 −1.42137 
                 0.0069 
               
               
                 26 
                 −13.17290 
                 0.0803 
                 1.57099 
                 50.80 
                 0.55887 
                 S-BAL2 
               
               
                 27 
                 −3.29527 
                 0.3510 
               
               
                 28 
                 ∞ 
                 0.1672 
                 1.58913 
                 61.14 
                 0.54067 
                 S-BAL35 
               
               
                 29 
                 −1.46758 
                 0.8775 
               
               
                 30 
                 ∞ 
                 0.0793 
                 1.51633 
                 64.14 
                 0.53531 
                 S-BSL7 
               
               
                 31 
                 ∞ 
                 0.2757 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Example 1/Specs (d-line) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Zoom Ratios 
                 1.0 
               
               
                   
                 f′ 
                 1.00 
               
               
                   
                 Bf′ 
                 1.21 
               
               
                   
                 FNo. 
                 1.90 
               
               
                   
                 2ω [°] 
                 58.4 
               
               
                   
                   
               
            
           
         
       
     
     Referring to Table 1 below, the Abbe number, the partial dispersion ratio, and the refractive index of each of the lenses which constitutes the imaging lens of Example 1 will be described. 
     The Abbe number vd 1  of the first lens L 11  is 42.73. This value satisfies the suitable numerical conditions with respect to the first lens described above, i.e., the conditions that the Abbe number vd 1  is greater than or equal to 30, and more preferably greater than or equal to 35. In the case that the Abbe number vd 1  of the first lens L 11  is greater than or equal to 30, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number vd 1  of the first lens L 11  is greater than or equal to 35. 
     The Abbe number vd 2  of the second lens L 12  is 81.54. This value satisfies the suitable numerical conditions with respect to the second lens described above, i.e., the conditions that the Abbe number vd 2  is greater than or equal to 50, more preferably greater than or equal to 55, even more preferably greater than or equal to 60, and still more preferably greater than or equal to 65. In the case that the Abbe number vd 2  of the second lens L 12  is greater than or equal to 50, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number vd 2  of the second lens L 12  is greater than or equal to 55, even more prominent in the case that the Abbe number vd 2  of the second lens L 12  is greater than or equal to 60, and still more prominent in the case that the Abbe number vd 2  of the second lens L 12  is greater than or equal to 65. 
     The Abbe number vd 3  of the third lens L 13  is 23.78. This value satisfies the suitable numerical conditions with respect to the third lens described above, i.e., the conditions that the Abbe number vd 3  is less than or equal to 30, more preferably less than or equal to 28, and even more preferably less than or equal to 27. In the case that the Abbe number vd 3  of the third lens L 13  is less than or equal to 30, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number vd 3  of the third lens L 13  is less than or equal to 28, and even more prominent in the case that the Abbe number vd 3  of the third lens L 13  is less than or equal to 27. 
     Further, the above Abbe number of the third lens L 13  which is 23.78 also satisfies other suitable numerical conditions with respect to the third lens described above, i.e., the condition that the Abbe number vd 3  is greater than or equal to 20. In the case that the Abbe number vd 3  is greater than or equal to 20, reduction in the cost of the material for the third lens L 13  will be facilitated. 
     Further, the partial dispersion ratio θg,F 3  of the third lens L 13  is 0.62072. This value and the above Abbe number of 23.78 satisfy the suitable numerical conditions with respect to the third lens described above, i.e., the conditions that the Abbe number vd 3  is between 15 and 30; and the partial dispersion ratio θg,F 3  is greater than or equal to 0.6, and more preferably greater than or equal to 0.61. In the case that the Abbe number vd 3  of the third lens L 13  is between 15 and 30 and the partial dispersion ratio θg,F 3  is greater than or equal to 0.6, correction of lateral chromatic aberration will be facilitated. Further, this advantageous effect will become more prominent in the case that the partial dispersion ratio is greater than or equal to 0.61. 
     The Abbe number vd 4  of the fourth lens L 14  is 31.32. This value satisfies the suitable numerical conditions with respect to the fourth lens described above, i.e., the conditions that the Abbe number vd 4  is less than or equal to 40, and more preferably less than or equal to 35. In the case that the Abbe number vd 4  of the fourth lens L 14  is less than or equal to 40, favorable correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number vd 4  is less than or equal to 35. 
     The partial dispersion ratio θg,F 4  of the fourth lens L 14  is 0.59481. This value and the above Abbe number of 31.32 satisfy the suitable numerical conditions with respect to the fourth lens described above, i.e., the conditions that the Abbe number vd 4  is between 22 and 40 and the partial dispersion ratio θg,F 4  is greater than or equal to 0.58. In the case that the above Abbe number vd 4  of the fourth lens L 14  is between 22 and 40 and the partial dispersion ratio θg,F 4  is greater than or equal to 0.58, correction of lateral chromatic aberration will be facilitated. 
     The Abbe number vd 5  of the fifth lens L 15  is 31.32. This value satisfies the suitable numerical conditions with respect to the fifth lens described above, i.e., the conditions that the Abbe number vd 5  is less than or equal to 40, and more preferably less than or equal to 35. In the case that the Abbe number vd 5  of the fifth lens L 15  is less than or equal to 40, favorable correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number vd 5  is less than or equal to 35. 
     The partial dispersion ratio θg,F 5  of the fifth lens L 15  is 0.59481. This value and the above Abbe number of 31.32 satisfy the suitable numerical conditions with respect to the fifth lens described above, i.e., the conditions that the Abbe number vd 5  is between 22 and 40 and the partial dispersion ratio θg,F 5  is greater than or equal to 0.58. In the case that the above Abbe number vd 5  of the fifth lens L 15  is between 22 and 40 and the partial dispersion ratio θg,F 5  is greater than or equal to 0.58, correction of lateral chromatic aberration will be facilitated. 
     The Abbe number vd 6  of the sixth lens L 16  is 41.50. This value satisfies the suitable numerical conditions with respect to the sixth lens described above, i.e., the conditions that the Abbe number vd 6  is less greater or equal to 25, and more preferably greater than or equal to 30. In the case that the Abbe number vd 6  of the sixth lens L 16  is greater than or equal to 25, favorable correction of longitudinal chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number vd 6  is greater than or equal to 30. 
     The Abbe number vd 6  of the sixth lens L 16  which is 41.50 satisfies another suitable numerical conditions described above, i.e., the conditions that the Abbe number vd 6  is less than or equal to 55, and more preferably less than or equal to 50. In the case that the Abbe number vd 6  of the sixth lens L 16  is less than or equal to 55, correction of lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number vd 6  is less than or equal to 50. 
     The Abbe number of the seventh lens L 17  is 23.78. This value satisfies the suitable numerical conditions with respect to the seventh lens described above, i.e., the conditions that the Abbe number vd 7  is greater than or equal to 15, more preferably greater than or equal to 18, and even more preferably greater than or equal to 20. In the case that the Abbe number vd 7  of the seventh lens L 17  is greater than or equal to 15, reduction in the cost of the material for the seventh lens L 17  will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number vd 7  is greater than or equal to 18, and even more prominent in the case that the Abbe number vd 7  is greater than or equal to 20. 
     The Abbe number vd 7  of the seventh lens L 17  which is 23.78 also satisfies another suitable numerical conditions with respect to the seventh lens described above, i.e., the conditions that the Abbe number vd 7  is less than or equal to 33, more preferably less than or equal to 30, and even more preferably less than or equal to 28. In the case that the Abbe number vd 7  of the seventh lens L 17  is less than or equal to 33, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number vd 7  is less than or equal to 30, and even more prominent in the case that the Abbe number vd 7  is less than or equal to 28. 
     The Abbe number vd 8  of the eighth lens L 18  is 81.54. This value satisfies the suitable numerical conditions with respect to the eighth lens described above, i.e., the conditions that the Abbe number vd 8  is greater than or equal to 50, more preferably greater than or equal to 55, even more preferably greater than or equal to 60, and still more preferably greater than or equal to 70. In the case that the Abbe number vd 8  of the eighth lens L 18  is greater than or equal to 50, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number vd 8  is greater than or equal to 55, even more prominent in the case that the Abbe number vd 8  is greater than or equal to 60, and still more prominent in the case that the Abbe number vd 8  is greater than or equal to 70. 
     Meanwhile, the Abbe number vd 9  of the ninth lens L 19  which is the most-image-side lens of the first lens group G 1  is 23.78. This value satisfies the suitable numerical conditions with respect to the most-image-side lens of the first lens group described above, i.e., the conditions that the Abbe number vd 9  is less than or equal to 40, more preferably less than or equal to 30, and even more preferably less than or equal to 28. In the case that the Abbe number of the most-image-side lens of the first lens group is less than or equal to 40, correction of longitudinal chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number is less than or equal to 30, and even more prominent in the case that the Abbe number is less than or equal to 28. 
     The Abbe number vd 8  of the eighth lens L 18  which is the lens that is second from the most-image side in the first lens group G 1  is 81.54 as described above. This value satisfies the suitable numerical conditions with respect to the lens which is second from the most-image side in the first lens group described above, i.e., the conditions that the Abbe number vd 8  is greater than or equal to 50, more preferably greater than or equal to 55, even more preferably greater than or equal to 60, and still more preferably greater than or equal to 65. In the case that the Abbe number of the lens which is second from the most-image side in the first lens group G 1  is greater than or equal to 50, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number is greater than or equal to 55, even more prominent In the case that the Abbe number is greater than or equal to 60, and still more prominent in the case that the Abbe number is greater than or equal to 65. 
     The Abbe number vd 7  of the seventh lens L 17  which is the lens that is third from the most-image side in the first lens group G 1  is 23.78 as described above. This value satisfies the suitable numerical conditions with respect to the lens which is third from the most-image side in the first lens group described above, i.e., the conditions that the Abbe number vd 7  is less than or equal to 30, more preferably less than or equal to 28, and even more preferably less than or equal to 26. In the case that the Abbe number of the lens which is third from the most-image side in the first lens group G 1  is less than or equal to 30, correction of longitudinal chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number is less than or equal to 28, and even more prominent in the case that the Abbe number is less than or equal to 26. 
     Meanwhile, the Abbe number vd 10  of the positive lens L 21  which is the most-object-side lens of the second lens group G 2  is 46.57. This value satisfies the suitable numerical conditions with respect to the most-object-side lens of the second lens group described above, i.e., the conditions that the Abbe number vd 10  is greater than or equal to 30, more preferably greater than or equal to 35, and even more preferably greater than or equal to 38. In the case that the Abbe number of the most-object-side lens of the second lens group is greater than or equal to 30, correction of longitudinal chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number is greater than or equal to 35, and even more prominent in the case that the Abbe number is less than or equal to 38. 
     The Abbe number vd 11  of the negative lens L 22  which is the lens that is second from the most-object side in the second lens group G 2  is 35.70. This value satisfies the suitable numerical conditions with respect to the lens which is second from the most-object side in the second lens group described above, i.e., the conditions that the Abbe number vd 11  is greater than or equal to 20, and more preferably greater than or equal to 30. In the case that the Abbe number of the lens which is second from the most-object side in the second lens group G 2  is greater than or equal to 20, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number of the lens which is second from the most-object side in the second lens group G 2  is greater than or equal to 30. 
     The Abbe number vd 12  of the positive lens L 23  which is the lens that is third from the most-object side in the second lens group G 2  is 81.54. This value satisfies the suitable numerical conditions with respect to the lens which is third from the most-object side in the second lens group described above, i.e., the conditions that the Abbe number vd 12  is greater than or equal to 40, more preferably greater than or equal to 50, and even more preferably greater than or equal to 60. In the case that the Abbe number of the lens which is third from the most-object side in the second lens group G 2  is greater than or equal to 40, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number of the lens which is third from the most-object side in the second lens group G 2  is greater than or equal to 50, and even more prominent in the case that the Abbe number is greater than or equal to 60. 
     The Abbe number vd 13  of the negative lens L 24  which is the lens that is fourth from the most-object side in the second lens group G 2  is 23.78. This value satisfies the suitable numerical conditions with respect to the lens which is fourth from the most-object side in the second lens group described above, i.e., the conditions that the Abbe number vd 13  is less than or equal to 30, more preferably less than or equal to 29, and even more preferably less than or equal to 28. In the case that the Abbe number of the lens which is fourth from the most-object side in the second lens group G 2  is less than or equal to 30, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number of the lens which is fourth from the most-object side in the second lens group G 2  is less than or equal to 29, and even more prominent in the case that the Abbe number is less than or equal to 28. 
     The second lens group G 2  includes a cemented lens formed by cementing the positive lens L 23  and the negative lens L 24  together, as described above. The Abbe number vd 12  of the positive lens L 23  which constitutes this cemented lens is 81.54 as described above. This value satisfies the suitable numerical conditions with respect to the positive lens which constitutes the cemented lens of the second lens group described above, i.e., the conditions that the Abbe number vd 12  is greater than or equal to 40, more preferably greater than or equal to 50, and even more preferably greater than or equal to 60. In the case that the Abbe number of the positive lens which constitutes the cemented lens used for the second lens group G 2  is greater than or equal to 40, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number is greater than or equal to 50, and even more prominent in the case that the Abbe number is greater than or equal to 60. 
     The Abbe number vd 13  of the negative lens L 24  which constitutes the above cemented lens is 23.78 as described above. This value satisfies the suitable numerical conditions with respect to the negative lens which constitutes the cemented lens of the second lens group described above, i.e., the conditions that the Abbe number vd 13  is less than or equal to 30, more preferably less than or equal to 29, and even more preferably less than or equal to 28. In the case that the Abbe number of the negative lens which constitutes the cemented lens used for the second lens group G 2  is less than or equal to 30, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number is less than or equal to 29, and even more prominent in the case that the Abbe number is less than or equal to 28. 
     The Abbe number vd 15  of the positive lens L 26  which is the most-image-side lens of the second lens group G 2  is 61.14. This value satisfies the suitable numerical conditions with respect to the most-image-side lens of the second lens group described above, i.e., the conditions that the Abbe number vd 15  is greater than or equal to 40, more preferably greater than or equal to 45, and even more preferably greater than or equal to 50. In the case that the Abbe number of the most-image-side lens in the second lens group G 2  is greater than or equal to 40, correction of lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number is greater than or equal to 45, and even more prominent in the case that the Abbe number is greater than or equal to 50. 
     The Abbe number vd 14  of the positive lens L 25  which is the lens that is second from the most-image side in the second lens group G 2  is 50.80. This value satisfies the suitable numerical conditions with respect to the lens that is second from the most-image side in the second lens group described above, i.e., the conditions that the Abbe number vd 14  is greater than or equal to 40, more preferably greater than or equal to 45, and even more preferably greater than or equal to 48. In the case that the Abbe number of the lens that is second from the most-image side in the second lens group described above is greater than or equal to 40, correction of lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number is greater than or equal to 45, and even more prominent in the case that the Abbe number is greater than or equal to 48. 
     Meanwhile, the refractive index Nd 1  of the first lens L 11  is 1.83481. This value satisfies the suitable numerical conditions with respect to the first lens described above, i.e., the conditions that the refractive index Nd 1  is greater than 1.7, and more preferably greater than 1.75. In the case that the refractive index Nd 1  of the first lens L 11  is greater than 1.7, increasing the power of the first lens L 11  will be facilitated and correcting distortion will be also facilitated. This advantageous effect will become prominent in the case that the refractive index Nd 1  of the first lens L 11  is greater than 1.75. 
     Further, the refractive index of the first lens L 11  which is 1.83481 satisfies another suitable numerical condition with respect to the first lens described above, i.e., the condition that the refractive index is less than 1.9. In the case that the refractive index Nd 1  of the first lens L 11  is less than 1.9, suppression of the cost of the material for the first lens L 11  will be facilitated. 
       FIG. 9  shows the respective aberration diagrams of the imaging lens of Example 1.  FIG. 9  shows spherical aberration, sine condition, astigmatism, distortion, and lateral chromatic aberration in this order from the left to the right. Note that these aberrations are for when the imaging lens is focused on the object at infinity. 
     Each of the aberration diagrams of spherical aberration, sine condition, astigmatism, and distortion shows an aberration with respect to the d-line (wavelength: 587.6 nm) as the reference wavelength. The spherical aberration diagram illustrates aberrations with respect to the-d line, the C-line (wavelength of 656.3 nm), the F-line (wavelength of 486.1 nm), and the g-line (wavelength of 435.8 nm) respectively indicated by a solid line, a broken line, a dotted line, and a narrow line. In the astigmatism diagrams, the solid line illustrates aberration in the sagittal direction while the broken line illustrates aberration in the tangential direction. The lateral chromatic aberration diagram illustrates aberrations with respect to the c-line, the F-line and the g-line respectively indicated by the broken line, the dotted line, and the narrow line. Note that Fno. in the spherical aberration and the sign condition diagram represents the F-number, and ω in the other aberration diagrams represents the half angle of view. 
     The manner in which each of the aberration diagrams described above is shown is the same for  FIGS. 10 through 15 . 
     Example 2 
     A cross-sectional view illustrating the lens configuration of an imaging lens of Example 2 is shown in  FIG. 3 . Referring to  FIG. 3 , a schematic configuration of the imaging lens of Example 2 will be described. This imaging lens consists of a first lens group G 1  having a positive refractive power and a second lens group G 2  having a positive refractive power in this order from the object side along the optical axis Z. Focusing is performed by moving the entirety of the second lens group G 2  along the optical axis Z. 
     The first lens group G 1  consists of a positive first lens L 11 , a negative second lens L 12 , a negative third lens L 13 , a positive fourth lens L 14 , a positive fifth lens L 15 , a negative sixth lens L 16 , a negative seventh lens L 17 , a positive eighth lens L 18 , a positive ninth lens L 19 , and a positive tenth lens L 110  in this order from the object side along the optical axis Z. Note that the seventh lens L 17  and the eighth lens L 18  are cemented to each other, and the ninth lens L 19  and the tenth lens L 110  are cemented to each other. 
     Meanwhile, the second lens group G 2  consists of a positive lens L 21 , a negative lens L 22 , a positive lens L 23 , a negative lens L 24 , and a positive lens L 25  in this order from the object side along the optical axis Z. Note that the positive lens L 23  and the negative lens L 24  are cemented to each other. 
     An aperture stop St is disposed between the first lens group G 1  and the second lens group G 2 .  FIG. 3  also shows the example in which a plane parallel optical member PP is disposed between the second lens group G 2  and the imaging plane Sim. 
     As described above, when compared to the imaging lens of Example 1, the imaging lens of Example 2 basically differs from the imaging lens of Example 1 in that the first lens group G 1  in Example 2 consists of ten lenses (nine lenses in Example 1) while the second lens group G 2  in Example 2 consists of five lenses (six lenses in Example 1). 
     In the imaging lens of Example 2, the power arrangement of the first lens L 11  through the ninth lens L 19  toward the image side in the first lens group G 1  is the same as the power arrangement in Example 1. However, the positive fifth lens L 15  in the imaging lens of Example 1 is a planoconvex lens, whereas the fifth lens L 15  in the imaging lens of Example 2 is a positive meniscus lens. 
     In the imaging lens of Example 2, the power arrangement of the positive lens L 21  through the positive lens L 25  toward the image side in the second lens group G 2  is the same as the power arrangement in Example 1. However, the positive lens L 25  in the imaging lens of Example 1 is a positive meniscus lens, whereas the positive lens L 25  in the imaging lens of Example 2 is a biconvex lens. 
     The first lens group G 1  includes a cemented lens formed by cementing the seventh lens L 17  and the eighth lens L 18  together. This cemented lens is formed by cementing one positive lens (the eighth lens L 18 ) and one negative lens (the seventh lens L 17 ) together. Configuring the first lens group G 1  to include such a cemented lens enables longitudinal chromatic aberration and lateral chromatic aberration to be favorably corrected. 
     Each of a lens which is first from the most-image side in the first lens group G 1 , a lens which is second from the most-image side in the first lens group G 1 , and a lens which is third from the most-image side in the first lens group G 1  which are respectively the tenth lens  110 , the ninth lens L 19 , and the eighth lens L 18  is a meniscus lens. Such a configuration facilitates correction of spherical aberration, astigmatism, and comatic aberration. 
     Each of a lens which is first from the most-image side in the first lens group G 1 , a lens which is second from the most-image side in the first lens group G 1 , and a lens which is third from the most-image side in the first lens group G 1  which are respectively the tenth lens L 10 , the ninth lens L 19 , and the eighth lens L 18  is a lens with a convex surface toward the image side. This facilitates correction of spherical aberration and astigmatism. 
     The most-image-side lens in the first lens group G 1  which is the tenth lens L 110  is configured to be a positive meniscus lens. This facilitates favorable correction of astigmatism and comatic aberration. 
     In the imaging lens of Example 2, the shape of each of the first lens L 11  through the ninth lens L 19  of the first lens group G 1  is basically the same as that of the imaging lens of Example 1 except for the fifth lens L 15  to be described later. Therefore, the advantageous effect obtained based on the shapes of the lenses L 11  through L 14  and lens L 16  through L 19  is also substantially the same as in Example 1. 
     A planoconvex lens is employed for the fifth lens L 15  in the imaging lens of Example 1, whereas a positive meniscus lens with a convex surface toward the object side is employed for the fifth lens L 15  in the imaging lens of Example 2. Configuring the fifth lens L 15  to be a positive meniscus lens with a convex surface toward the object side also facilitates correction of spherical aberration and astigmatism. 
     The basic shape of each of the positive lens L 21  through the positive lens L 24  of the second lens group G 2  is the same as that of the imaging lens of Example 1. Therefore, the advantageous effect obtained based on the shapes of these lenses L 21  through L 24  is also the same as in Example 1. 
     A positive meniscus lens is employed for the positive lens L 25  in the imaging lens of Example 1, whereas a biconvex lens is employed for the positive lens L 25  in the imaging lens of Example 2. In this case as well, configuring the most-image-side lens of the second lens group G 2  to be the positive lens L 25  facilitates suppression of the angles at which the peripheral rays enter the image sensor. 
     The positive lens L 25  which is the most-image-side lens and the positive lens L 24  which is the lens which is second from the most-image side in the second lens group G 2  are lenses with convex surfaces toward the image side, in particular. This facilitates suppression of the angles at which the peripheral rays enter the image sensor. 
     The object-side surface of the first lens L 11  which is the most-object-side lens of the first lens group G 1 , the image-side surface of the tenth lens L 110  which is the most-image-side lens of the first lens group G 1 , the object-side surface of the positive lens L 21  which is the most-object-side lens of the second lens group G 2 , and the image-side surface of the positive lens L 25  which is the most-image-side lens of the second lens group G 2  are all convex surfaces. This facilitates correction of astigmatism, comatic aberration, and distortion. 
     Table 3 shows basic lens data of the imaging lens of Example 2. Further, Table 4 shows specs of the imaging lens of Example 2 with respect to the d-line. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Example 2/Lens Data 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Di 
                   
                   
                 θ g, F j 
                   
               
               
                 Si 
                 Ri 
                 Distances 
                 Ndj 
                 ν dj 
                 Partial 
               
               
                 Surface 
                 Radii of 
                 Between 
                 Refractive 
                 Abbe 
                 Dispersion 
                 Names of 
               
               
                 Numbers 
                 Curvature 
                 Surfaces 
                 Indices 
                 Numbers 
                 Ratios 
                 Materials 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 1 
                 3.37287 
                 0.1793 
                 1.83481 
                 42.73 
                 0.56486 
                 S-LAH55V 
               
               
                 2 
                 −46.72174 
                 0.0069 
               
               
                 3 
                 1.58542 
                 0.0760 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 4 
                 0.72283 
                 0.3232 
               
               
                 5 
                 −2.59940 
                 0.0518 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 6 
                 1.13076 
                 0.3210 
               
               
                 7 
                 −2.75548 
                 0.2671 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 8 
                 −1.52870 
                 0.1449 
               
               
                 9 
                 1.33416 
                 0.1899 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 10 
                 19.39212 
                 0.2145 
               
               
                 11 
                 −4.61895 
                 0.0518 
                 1.54814 
                 45.79 
                 0.56859 
                 S-TIL1 
               
               
                 12 
                 1.84686 
                 0.1191 
               
               
                 13 
                 −1.38631 
                 0.0518 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 14 
                 −4.19589 
                 0.1040 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 15 
                 −1.49515 
                 0.0069 
               
               
                 16 
                 −24.78220 
                 0.0579 
                 1.71299 
                 53.87 
                 0.54587 
                 S-LAL8 
               
               
                 17 
                 −4.06038 
                 0.0967 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 18 
                 −1.78008 
                 0.0794 
               
               
                 19(Stop) 
                 ∞ 
                 0.2305 
               
               
                 20 
                 2.99508 
                 0.1082 
                 1.80400 
                 46.57 
                 0.55724 
                 S-LAH65 
               
               
                 21 
                 −7.65353 
                 0.1700 
               
               
                 22 
                 5.54483 
                 0.0414 
                 1.62588 
                 35.70 
                 0.58935 
                 S-TIM1 
               
               
                 23 
                 1.07242 
                 0.0670 
               
               
                 24 
                 2.88794 
                 0.3350 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 25 
                 −0.63308 
                 0.0622 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 26 
                 −1.49754 
                 0.3705 
               
               
                 27 
                 24.94631 
                 0.2107 
                 1.71299 
                 53.87 
                 0.54587 
                 S-LAL8 
               
               
                 28 
                 −1.46200 
                 0.8781 
               
               
                 29 
                 ∞ 
                 0.0794 
                 1.51633 
                 64.14 
                 0.53531 
                 S-BSL7 
               
               
                 30 
                 ∞ 
                 0.2622 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 4 
               
               
                   
               
               
                 Example 2/Specs (d-line) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Zoom Ratios 
                 1.0 
               
               
                   
                 f′ 
                 1.00 
               
               
                   
                 Bf′ 
                 1.19 
               
               
                   
                 FNo. 
                 1.91 
               
               
                   
                 2ω [°] 
                 58.4 
               
               
                   
                   
               
            
           
         
       
     
     Referring to Table 3 below, the Abbe number, the partial dispersion ratio, and the refractive index of each of the lenses which constitute the imaging lens of Example 2 will be described. 
     All of the values of the Abbe numbers of the first lens L 11  through the eighth lens L 18  and the partial dispersion ratios of the fourth lens L 14  and the fifth lens L 15  satisfy the suitable numerical conditions described above. Therefore, the advantageous effect obtained by the values of these Abbe numbers and the partial dispersion ratios are also the same as those of Example 1. 
     Further, the Abbe number vd 10  of the tenth lens L 110  which is the most-image-side lens in the first lens group G 1  is 23.78. This value satisfies the suitable numerical conditions with respect to the most-image-side lens of the first lens described above, i.e., the conditions that the Abbe number vd 10  is less than or equal to 30, and more preferably less than or equal to 28. In the case that the Abbe number of the most-image-side lens of the first lens group G 1  is less than or equal to 30, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number is less than or equal to 28. 
     The Abbe number vd 9  of the ninth lens L 19  which is the lens that is second from the most-image side in the first lens group G 1  is 53.87. This value satisfies the suitable numerical conditions with respect to the lens that is second from the most-image side in the first lens group, i.e., the condition that the Abbe number vd 9  is greater than or equal to 50. In the case that the Abbe number of the lens that is second from the most-image side in the first lens group G 1  is greater than or equal to 50, correction of longitudinal chromatic aberration and lateral chromatic aberration will be facilitated. 
     The Abbe numbers of the positive lenses L 21  through L 24  of the second lens group G 2  are the same as those of Example 1. Accordingly, the advantageous effect obtained by these Abbe numbers is also the same as that of Example 1. 
     The Abbe number vd 15  of the positive lens L 25  which is the most-image-side lens of the second lens group G 2  is 53.87. This value satisfies the suitable numerical conditions with respect to the most-image-side lens of the second lens group described above, i.e., the conditions that the Abbe number vd 15  is greater than or equal to 40, more preferably greater than or equal to 45, and even more preferably greater than or equal to 50. In the case that the Abbe number of the most-image-side lens of the second lens group G 2  is greater than or equal to 40, correction of lateral chromatic aberration will be facilitated. This advantageous effect will become more prominent in the case that the Abbe number is greater than or equal to 45, and even more prominent in the case that the Abbe number is greater than or equal to 50. 
     The refractive index Nd 1  of the first lens L 11  is the same as the value in Example 1. Therefore, the advantageous effect obtained by the value of the refractive index Nd 1  is also the same as that of Example 1. 
       FIG. 10  shows the respective aberration diagrams of the imaging lens of Example 2. 
     Example 3 
     A cross-sectional view illustrating the lens configuration of an imaging lens of Example 3 is shown in  FIG. 4 . Referring to  FIG. 4 , a schematic configuration of the imaging lens of Example 3 will be described. This imaging lens consists of a first lens group G 1  having a positive refractive power and a second lens group G 2  having a positive refractive power in this order from the object side along the optical axis Z. Focusing is performed by moving the entirety of the second lens group G 2  along the optical axis Z. 
     An aperture stop St is disposed between the first lens group G 1  and the second lens group G 2 . 
     The number of lenses which respectively constitute the first lens group G 1  and the second lens group G 2 , the lens power arrangement, and the basic shape of each lens are the same as those in the imaging lens of Example 2. Accordingly, the advantageous effects obtained by the number of the lenses, the lens power arrangement, and the basic shape of each lens are the same as those in the imaging lens of Example 2. 
     Table 5 shows basic lens data of the imaging lens of Example 3. Further, Table 6 shows specs with respect to the d-line of the imaging lens of Example 3. 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Example 3/Lens Data 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Di 
                   
                   
                 θ g, F j 
                   
               
               
                 Si 
                 Ri 
                 Distances 
                 Ndj 
                 ν dj 
                 Partial 
               
               
                 Surface 
                 Radii of 
                 Between 
                 Refractive 
                 Abbe 
                 Dispersion 
                 Names of 
               
               
                 Numbers 
                 Curvature 
                 Surfaces 
                 Indices 
                 Numbers 
                 Ratios 
                 Materials 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 1 
                 3.35073 
                 0.1767 
                 1.83481 
                 42.73 
                 0.56486 
                 S-LAH55V 
               
               
                 2 
                 −50.48717 
                 0.0069 
               
               
                 3 
                 1.57922 
                 0.0759 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 4 
                 0.70842 
                 0.3264 
               
               
                 5 
                 −2.36526 
                 0.0517 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 6 
                 1.19743 
                 0.2611 
               
               
                 7 
                 −2.83837 
                 0.2854 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 8 
                 −1.48586 
                 0.1845 
               
               
                 9 
                 1.39654 
                 0.2379 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 10 
                 16.98863 
                 0.1540 
               
               
                 11 
                 −6.25730 
                 0.0517 
                 1.54814 
                 45.79 
                 0.56859 
                 S-TIL1 
               
               
                 12 
                 1.98962 
                 0.1222 
               
               
                 13 
                 −1.29220 
                 0.0666 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 14 
                 −3.82381 
                 0.1108 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 15 
                 −1.47044 
                 0.0116 
               
               
                 16 
                 −24.38820 
                 0.0559 
                 1.71299 
                 53.87 
                 0.54587 
                 S-LAL8 
               
               
                 17 
                 −3.70142 
                 0.0965 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 18 
                 −1.68493 
                 0.0793 
               
               
                 19(Stop) 
                 ∞ 
                 0.2448 
               
               
                 20 
                 2.61375 
                 0.0992 
                 1.80400 
                 46.58 
                 0.55730 
                 S-LAH65V 
               
               
                 21 
                 −10.39642 
                 0.2038 
               
               
                 22 
                 16.96094 
                 0.0414 
                 1.62588 
                 35.70 
                 0.58935 
                 S-TIM1 
               
               
                 23 
                 1.07771 
                 0.0673 
               
               
                 24 
                 2.93463 
                 0.3345 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 25 
                 −0.64905 
                 0.0621 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 26 
                 −1.49397 
                 0.3303 
               
               
                 27 
                 8.18307 
                 0.2165 
                 1.71299 
                 53.87 
                 0.54587 
                 S-LAL8 
               
               
                 28 
                 −1.58976 
                 0.8620 
               
               
                 29 
                 ∞ 
                 0.0793 
                 1.51633 
                 64.14 
                 0.53531 
                 S-BSL7 
               
               
                 30 
                 ∞ 
                 0.2760 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 6 
               
               
                   
               
               
                 Example 3/Specs (d-line) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Zoom Ratios 
                 1.0 
               
               
                   
                 f′ 
                 1.00 
               
               
                   
                 Bf′ 
                 1.19 
               
               
                   
                 FNo. 
                 1.90 
               
               
                   
                 2ω [°] 
                 58.4 
               
               
                   
                   
               
            
           
         
       
     
     Referring to Table 5 below, the Abbe number, the partial dispersion ratio, and the refractive index of each of the lenses which constitute the imaging lens of Example 3 will be described. 
     In the present Example, the Abbe number, the partial dispertion ratio, and the refractive index of each of the lenses which constitute the first lens group G 1  and the second lens group G 2  are the same as those in Example 2 except that the Abbe number vd 11  and the partial dispersion ratio θg,F 11  of a positive lens L 21  in the second lens group G 2  are respectively 46.58 and 0.55730. The value of the Abbe number vd 11  described above satisfies the suitable numerical conditions with respect to the most-object-side lens of the second lens group described above. Therefore, the advantageous effect obtained by the value of the Abbe number vd 11  is also the same as that of Example 1. 
       FIG. 11  shows the respective aberration diagrams of the imaging lens of Example 3. 
     Example 4 
     A cross-sectional view illustrating the lens configuration of an imaging lens of Example 4 is shown in  FIG. 5 . Referring to  FIG. 5 , a schematic configuration of the imaging lens of Example 4 will be described. This imaging lens consists of a first lens group G 1  having a positive refractive power and a second lens group G 2  having a positive refractive power in this order from the object side along the optical axis Z. Focusing is performed by moving the entirety of the second lens group G 2  along the optical axis Z. 
     An aperture stop St is disposed between the first lens group G 1  and the second lens group G 2 . 
     The number of lenses which respectively constitute the first lens group G 1  and the second lens group G 2  and the lens power arrangement are the same as those in the imaging lens of Example 1. Accordingly, the advantageous effects obtained by the number of the lenses and the lens power arrangement are the same as those in the imaging lens of Example 1. 
     A basic shape of each of the lenses which constitute the first lens group G 1  and the second lens group G 2  is the same of that of Example 1. However, the fifth lens L 15  of the first lens group G 1  and a positive lens L 26  of the second lens group G 2  are meniscus lenses (both are planoconvex lenses in Example 1). Therefore, the advantageous effect obtained by the basic shape of each lens is also the same as that of Example 1 except for what is specified below. 
     A fifth lens L 15  is a lens with a convex surface toward the object side. This facilitates correction of spherical aberration and astigmatism in the same manner as Example 1 in which the fifth lens L 15  is a planoconvex lens with a convex surface toward the object side. 
     Each of a positive lens L 26  which is the most-image-side lens of the second lens group G 2  and a positive lens L 25  which is second from the most-image side in the second lens group G 2  is a lens with a convex surface toward the image side. This will facilitate suppression of the angles at which the peripheral rays enter the image sensor in the present Example as well, in the same manner as in Example 1 in which a planoconvex lens is employed as the positive lens L 26 . 
     Table 7 shows basic lens data of the imaging lens of Example 4. Further, Table 8 shows specs with respect to the d-line of the imaging lens of Example 4. 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Example 4/Lens Data 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Di 
                   
                   
                 θ g, F j 
                   
               
               
                 Si 
                 Ri 
                 Distances 
                 Ndj 
                 ν dj 
                 Partial 
               
               
                 Surface 
                 Radii of 
                 Between 
                 Refractive 
                 Abbe 
                 Dispersion 
                 Names of 
               
               
                 Numbers 
                 Curvature 
                 Surfaces 
                 Indices 
                 Numbers 
                 Ratios 
                 Materials 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 1 
                 3.30522 
                 0.1533 
                 1.83481 
                 42.73 
                 0.56486 
                 S-LAH55V 
               
               
                 2 
                 −67.62341 
                 0.0069 
               
               
                 3 
                 1.57915 
                 0.0759 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 4 
                 0.69094 
                 0.3310 
               
               
                 5 
                 −2.21624 
                 0.0517 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 6 
                 1.22421 
                 0.3348 
               
               
                 7 
                 −2.59974 
                 0.2276 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 8 
                 −1.49813 
                 0.1470 
               
               
                 9 
                 1.45145 
                 0.1896 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 10 
                 −82.65258 
                 0.2004 
               
               
                 11 
                 −11.90692 
                 0.0517 
                 1.57501 
                 41.50 
                 0.57672 
                 S-TIL27 
               
               
                 12 
                 1.88873 
                 0.1348 
               
               
                 13 
                 −1.28411 
                 0.0517 
                 1.84666 
                 23.78 
                 0.62054 
                 S-TIH53 
               
               
                 14 
                 −3.59597 
                 0.1039 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 15 
                 −1.68311 
                 0.0069 
               
               
                 16 
                 −11.24043 
                 0.1000 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 17 
                 −1.70877 
                 0.0793 
               
               
                 18(Stop) 
                 ∞ 
                 0.2299 
               
               
                 19 
                 3.05158 
                 0.0888 
                 1.80400 
                 46.57 
                 0.55724 
                 S-LAH65 
               
               
                 20 
                 −14.43568 
                 0.2338 
               
               
                 21 
                 10.92975 
                 0.0414 
                 1.62588 
                 35.70 
                 0.58935 
                 S-TIM1 
               
               
                 22 
                 1.16199 
                 0.0493 
               
               
                 23 
                 3.37669 
                 0.3276 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 24 
                 −0.65083 
                 0.0864 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 25 
                 −1.41048 
                 0.0069 
               
               
                 26 
                 −11.91561 
                 0.0833 
                 1.66672 
                 48.32 
                 0.56101 
                 S-BAH11 
               
               
                 27 
                 −3.29631 
                 0.3673 
               
               
                 28 
                 145.83132 
                 0.1584 
                 1.58913 
                 61.14 
                 0.54067 
                 S-BAL35 
               
               
                 29 
                 −1.51938 
                 0.8768 
               
               
                 30 
                 ∞ 
                 0.0793 
                 1.51633 
                 64.14 
                 0.53531 
                 S-BSL7 
               
               
                 31 
                 ∞ 
                 0.2759 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 8 
               
               
                   
               
               
                 Example 4/Specs (d-line) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Zoom Ratios 
                 1.0 
               
               
                   
                 f′ 
                 1.00 
               
               
                   
                 Bf′ 
                 1.20 
               
               
                   
                 FNo. 
                 1.90 
               
               
                   
                 2ω [°] 
                 58.4 
               
               
                   
                   
               
            
           
         
       
     
     Referring to Table 7 below, the Abbe number, the partial dispersion ratio, and the refractive index of each of the lenses which constitute the imaging lens of Example 4 will be described. 
     In the present Example, the Abbe number, the partial dispertion ratio, and the refractive index of each of the lenses which constitute the first lens group G 1  and the second lens group G 2  are the same as those in Example 1 except that the Abbe number vd 14 , the partial dispersion ratio θg,F 14 , and the refractive index Nd 14  of a positive lens L 25  in the second lens group G 2  are respectively 48.32, 0.56101, and 1.66672. The value of the Abbe number vd 14  described above satisfies the suitable numerical conditions (with respect to the lens which is second from the most-image side in the second lens group). Therefore, the advantageous effect obtained by the value of the Abbe number vd 14  is also the same as that of Example 1. 
       FIG. 12  shows the respective aberration diagrams of the imaging lens of Example 4. 
     Example 5 
     A cross-sectional view illustrating the lens configuration of an imaging lens of Example 5 is shown in  FIG. 6 . Referring to  FIG. 6 , a schematic configuration of the imaging lens of Example 5 will be described. This imaging lens consists of a first lens group G 1  having a positive refractive power and a second lens group G 2  having a positive refractive power in this order from the object side along the optical axis Z. Focusing is performed by moving the entirety of the second lens group G 2  along the optical axis Z. 
     An aperture stop St is disposed between the first lens group G 1  and the second lens group G 2 . 
     The number of lenses which respectively constitute the first lens group G 1  and the second lens group G 2  and the lens power arrangement are the same as those in the imaging lens of Example 1. Accordingly, the advantageous effects obtained by the number of the lenses and the lens power arrangement are the same as those in the imaging lens of Example 1. 
     A basic shape of each of the lenses which constitute the first lens group G 1  and the second lens group G 2  is the same of that of Example 1. However, the fifth lens L 15  of the first lens group G 1  and a positive lens L 26  of the second lens group G 2  are meniscus lenses (both are planoconvex lenses in Example 1). Therefore, the advantageous effect obtained by the basic shape of each lens is also the same as that of Example 1 except for what is specified below. 
     A fifth lens L 15  is a lens with a convex surface toward the object side. This facilitates correction of spherical aberration and astigmatism in the same manner as Example 1 in which the fifth lens L 15  is a planoconvex lens with a convex surface toward the object side. 
     Configuring the fifth lens L 15  to be a positive meniscus lens with a convex surface toward the object side facilitates correction of spherical aberration and astigmatism. 
     Each of a positive lens L 26  which is the most-image-side lens of the second lens group G 2  and a positive lens L 25  which is second from the most-image side in the second lens group G 2  is a lens with a convex surface toward the image side. This will facilitate suppression of the angles at which the peripheral rays enter the image sensor in the present Example as well, in the same manner as in Example 1 in which a planoconvex lens is employed as the positive lens L 26 . 
     Table 9 shows basic lens data of the imaging lens of Example 5. Further, Table 10 shows specs with respect to the d-line of the imaging lens of Example 5. 
     
       
         
           
               
             
               
                 TABLE 9 
               
             
            
               
                   
               
               
                 Example 5/Lens Data 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Di 
                   
                   
                 θ g, F j 
                   
               
               
                 Si 
                 Ri 
                 Distances 
                 Ndj 
                 ν dj 
                 Partial 
               
               
                 Surface 
                 Radii of 
                 Between 
                 Refractive 
                 Abbe 
                 Dispersion 
                 Names of 
               
               
                 Numbers 
                 Curvature 
                 Surfaces 
                 Indices 
                 Numbers 
                 Ratios 
                 Materials 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 1 
                 3.33402 
                 0.1711 
                 1.83481 
                 42.73 
                 0.56486 
                 S-LAH55V 
               
               
                 2 
                 −48.93901 
                 0.0069 
               
               
                 3 
                 1.55268 
                 0.0759 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 4 
                 0.68495 
                 0.3327 
               
               
                 5 
                 −2.12081 
                 0.0517 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 6 
                 1.21855 
                 0.3347 
               
               
                 7 
                 −2.70673 
                 0.2152 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 8 
                 −1.47883 
                 0.1355 
               
               
                 9 
                 1.40344 
                 0.1655 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 10 
                 92.44075 
                 0.2028 
               
               
                 11 
                 −10.94866 
                 0.0517 
                 1.57501 
                 41.50 
                 0.57672 
                 S-TIL27 
               
               
                 12 
                 1.82655 
                 0.1391 
               
               
                 13 
                 −1.30215 
                 0.0533 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 14 
                 −3.58510 
                 0.1054 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 15 
                 −1.70774 
                 0.0069 
               
               
                 16 
                 −10.07788 
                 0.1179 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 17 
                 −1.65891 
                 0.0793 
               
               
                 18(Stop) 
                 ∞ 
                 0.2299 
               
               
                 19 
                 3.24109 
                 0.0842 
                 1.80400 
                 46.57 
                 0.55724 
                 S-LAH65 
               
               
                 20 
                 −15.80457 
                 0.2405 
               
               
                 21 
                 11.06169 
                 0.0414 
                 1.62588 
                 35.70 
                 0.58935 
                 S-TIM1 
               
               
                 22 
                 1.15339 
                 0.0512 
               
               
                 23 
                 2.78348 
                 0.3185 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 24 
                 −0.64664 
                 0.0939 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 25 
                 −1.39621 
                 0.0069 
               
               
                 26 
                 −13.11757 
                 0.0727 
                 1.57099 
                 50.80 
                 0.55887 
                 S-BAL2 
               
               
                 27 
                 −3.33589 
                 0.3760 
               
               
                 28 
                 −257.55638 
                 0.1632 
                 1.58913 
                 61.14 
                 0.54067 
                 S-BAL35 
               
               
                 29 
                 −1.45735 
                 0.8768 
               
               
                 30 
                 ∞ 
                 0.0793 
                 1.51633 
                 64.14 
                 0.53531 
                 S-BSL7 
               
               
                 31 
                 ∞ 
                 0.2759 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 10 
               
               
                   
               
               
                 Example 5/Specs (d-line) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Zoom Ratios 
                 1.0 
               
               
                   
                 f′ 
                 1.00 
               
               
                   
                 Bf′ 
                 1.20 
               
               
                   
                 FNo. 
                 1.90 
               
               
                   
                 2ω [°] 
                 58.4 
               
               
                   
                   
               
            
           
         
       
     
     Referring to Table 9 below, the Abbe number, the partial dispersion ratio, and the refractive index of each of the lenses which constitute the imaging lens of Example 5 will be described. 
     In the present embodiment, the Abbe number, the partial dispertion ratio, and the refractive index of each of the lenses which constitute the first lens group G 1  and the second lens group G 2  are all the same as those in Example 1. Therefore, the advantageous effects obtained by the values of these Abbe numbers, the partial dispersion ratios, and the refractive indices are also the same as those of Example 1. 
       FIG. 13  shows the respective aberration diagrams of the imaging lens of Example 5. 
     Example 6 
     A cross-sectional view illustrating the lens configuration of an imaging lens of Example 6 is shown in  FIG. 7 . Referring to  FIG. 7 , a schematic configuration of the imaging lens of Example 6 will be described. This imaging lens consists of a first lens group G 1  having a positive refractive power and a second lens group G 2  having a positive refractive power in this order from the object side along the optical axis Z. Focusing is performed by moving the entirety of the second lens group G 2  along the optical axis Z. 
     An aperture stop St is disposed between the first lens group G 1  and the second lens group G 2 . 
     The number of lenses which respectively constitute the first lens group G 1  and the second lens group G 2  and the lens power arrangement are the same as those in the imaging lens of Example 1. Accordingly, the advantageous effects obtained by the number of the lenses and the lens power arrangement are the same as those in the imaging lens of Example 1. 
     A basic shape of each of the lenses which constitute the first lens group G 1  and the second lens group G 2  is the same of that of Example 1. However, the fifth lens L 15  of the first lens group G 1  and a positive lens L 26  of the second lens group G 2  are meniscus lenses (both are planoconvex lenses in Example 1). Therefore, the advantageous effect obtained by the basic shape of each lens is also the same as that of Example 1 except for what is specified below. 
     A fifth lens L 15  is a lens with a convex surface toward the object side. This facilitates correction of spherical aberration and astigmatism in the same manner as Example 1 in which the fifth lens L 15  is a planoconvex lens with a convex surface toward the object side. 
     Configuring the fifth lens L 15  to be a positive meniscus lens with a convex surface toward the object side facilitates correction of spherical aberration and astigmatism. 
     Each of a positive lens L 26  which is the most-image-side lens of the second lens group G 2  and a positive lens L 25  which is second from the most-image side in the second lens group G 2  is a lens with a convex surface toward the image side. This will facilitate suppression of the angles at which the peripheral rays enter the image sensor in the present Example as well, in the same manner as in Example 1 in which a planoconvex lens is employed as the positive lens L 26 . 
     Table 11 shows basic lens data of the imaging lens of Example 6. Further, Table 12 shows specs with respect to the d-line of the imaging lens of Example 6. 
     
       
         
           
               
             
               
                 TABLE 11 
               
             
            
               
                   
               
               
                 Example 6/Lens Data 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Di 
                   
                   
                 θ g, F j 
                   
               
               
                 Si 
                 Ri 
                 Distances 
                 Ndj 
                 ν dj 
                 Partial 
               
               
                 Surface 
                 Radii of 
                 Between 
                 Refractive 
                 Abbe 
                 Dispersion 
                 Names of 
               
               
                 Numbers 
                 Curvature 
                 Surfaces 
                 Indices 
                 Numbers 
                 Ratios 
                 Materials 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 1 
                 3.33808 
                 0.1712 
                 1.83481 
                 42.73 
                 0.56486 
                 S-LAH55V 
               
               
                 2 
                 −54.08572 
                 0.0069 
               
               
                 3 
                 1.56287 
                 0.0759 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 4 
                 0.68363 
                 0.3373 
               
               
                 5 
                 −2.11966 
                 0.0517 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 6 
                 1.22228 
                 0.3344 
               
               
                 7 
                 −2.69911 
                 0.2148 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 8 
                 −1.48146 
                 0.1333 
               
               
                 9 
                 1.40156 
                 0.1655 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 10 
                 105.03735 
                 0.2054 
               
               
                 11 
                 −10.87599 
                 0.0517 
                 1.57501 
                 41.50 
                 0.57672 
                 S-TIL27 
               
               
                 12 
                 1.82025 
                 0.1402 
               
               
                 13 
                 −1.30347 
                 0.0523 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 14 
                 −3.59050 
                 0.1042 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 15 
                 −1.71013 
                 0.0069 
               
               
                 16 
                 −9.91618 
                 0.1245 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 17 
                 −1.65930 
                 0.0793 
               
               
                 18(Stop) 
                 ∞ 
                 0.2299 
               
               
                 19 
                 3.22931 
                 0.0850 
                 1.80400 
                 46.57 
                 0.55724 
                 S-LAH65 
               
               
                 20 
                 −14.73196 
                 0.2424 
               
               
                 21 
                 10.86565 
                 0.0414 
                 1.62588 
                 35.70 
                 0.58935 
                 S-TIM1 
               
               
                 22 
                 1.15233 
                 0.0517 
               
               
                 23 
                 2.80882 
                 0.3173 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 24 
                 −0.64662 
                 0.0920 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 25 
                 −1.40016 
                 0.0069 
               
               
                 26 
                 −12.94907 
                 0.0819 
                 1.57099 
                 50.80 
                 0.55887 
                 S-BAL2 
               
               
                 27 
                 −3.32031 
                 0.3830 
               
               
                 28 
                 −220.07327 
                 0.1672 
                 1.58913 
                 61.14 
                 0.54067 
                 S-BAL35 
               
               
                 29 
                 −1.45500 
                 0.8768 
               
               
                 30 
                 ∞ 
                 0.0793 
                 1.51633 
                 64.14 
                 0.53531 
                 S-BSL7 
               
               
                 31 
                 ∞ 
                 0.2760 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 12 
               
               
                   
               
               
                 Example 6/Specs (d-line) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Zoom Ratios 
                 1.0 
               
               
                   
                 f′ 
                 1.00 
               
               
                   
                 Bf′ 
                 1.21 
               
               
                   
                 FNo. 
                 1.90 
               
               
                   
                 2ω [°] 
                 58.4 
               
               
                   
                   
               
            
           
         
       
     
     Referring to Table 11 below, the Abbe number, the partial dispersion ratio, and the refractive index of each of the lenses which constitute the imaging lens of Example 6 will be described. 
     In the present embodiment, the Abbe number, the partial dispertion ratio, and the refractive index of each of the lenses which constitute the first lens group G 1  and the second lens group G 2  are all the same as those in Example 1. Therefore, the advantageous effects obtained by the values of these Abbe numbers, the partial dispersion ratios, and the refractive indices are also the same as those of Example 1. 
       FIG. 14  shows the respective aberration diagrams of the imaging lens of Example 6. 
     Example 7 
     A cross-sectional view illustrating the lens configuration of an imaging lens of Example 7 is shown in  FIG. 8 . Referring to  FIG. 8 , a schematic configuration of the imaging lens of Example 7 will be described. This imaging lens consists of a first lens group G 1  having a positive refractive power and a second lens group G 2  having a positive refractive power in this order from the object side along the optical axis Z. Focusing is performed by moving the entirety of the second lens group G 2  along the optical axis Z. 
     An aperture stop St is disposed between the first lens group G 1  and the second lens group G 2 . 
     The number of lenses which respectively constitute the first lens group G 1  and the second lens group G 2  and the lens power arrangement are the same as those in the imaging lens of Example 1. Accordingly, the advantageous effects obtained by the number of the lenses and the lens power arrangement are the same as those in the imaging lens of Example 1. 
     A basic shape of each of the lenses which constitute the first lens group G 1  and the second lens group G 2  is the same of that of Example 1. However, the fifth lens L 15  of the first lens group G 1  is a positive meniscus lens (which is a planoconvex lens in Example 1). Therefore, the advantageous effect obtained by the basic shape of each lens is also the same as that of Example 1 except for what is specified below. 
     The fifth lens L 15  is a lens with a convex surface toward the object side. This facilitates correcting spherical aberration and astigmatism in the same manner as the imaging lens of Example 1 in which the fifth lens L 15  is a planoconvex lens with a convex surface toward the object side. 
     Further, configuring the fifth lens L 15  to be a positive meniscus lens with a convex surface toward the object side facilitates correcting spherical aberration and astigmatism. 
     Table 13 shows basic lens data of the imaging lens of Example 7. Further, Table 14 shows specs with respect to the d-line of the imaging lens of Example 7. 
     
       
         
           
               
             
               
                 TABLE 13 
               
             
            
               
                   
               
               
                 Example 7/Lens Data 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Di 
                   
                   
                 θ g, F j 
                   
               
               
                 Si 
                 Ri 
                 Distances 
                 Ndj 
                 ν dj 
                 Partial 
               
               
                 Surface 
                 Radii of 
                 Between 
                 Refractive 
                 Abbe 
                 Dispersion 
                 Names of 
               
               
                 Numbers 
                 Curvature 
                 Surfaces 
                 Indices 
                 Numbers 
                 Ratios 
                 Materials 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 1 
                 3.35715 
                 0.1652 
                 1.83481 
                 42.73 
                 0.56486 
                 S-LAH55V 
               
               
                 2 
                 −69.59278 
                 0.0069 
               
               
                 3 
                 1.56690 
                 0.0760 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 4 
                 0.68277 
                 0.3392 
               
               
                 5 
                 −2.12015 
                 0.0518 
                 1.80518 
                 25.42 
                 0.61616 
                 S-TIH6 
               
               
                 6 
                 1.21477 
                 0.3348 
               
               
                 7 
                 −2.73300 
                 0.2152 
                 1.83481 
                 42.73 
                 0.56486 
                 S-LAH55V 
               
               
                 8 
                 −1.47603 
                 0.1337 
               
               
                 9 
                 1.40467 
                 0.1657 
                 1.90366 
                 31.32 
                 0.59481 
                 TAFD25 
               
               
                 10 
                 112.23599 
                 0.2036 
               
               
                 11 
                 −10.80209 
                 0.0518 
                 1.57501 
                 41.50 
                 0.57672 
                 S-TIL27 
               
               
                 12 
                 1.82603 
                 0.1427 
               
               
                 13 
                 −1.30234 
                 0.0518 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 14 
                 −3.59743 
                 0.1039 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 15 
                 −1.71585 
                 0.0084 
               
               
                 16 
                 −9.92988 
                 0.1225 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 17 
                 −1.66531 
                 0.0794 
               
               
                 18(Stop) 
                 ∞ 
                 0.2157 
               
               
                 19 
                 3.22890 
                 0.0833 
                 1.80400 
                 46.57 
                 0.55724 
                 S-LAH65 
               
               
                 20 
                 −14.83331 
                 0.2418 
               
               
                 21 
                 10.80062 
                 0.0414 
                 1.62588 
                 35.70 
                 0.58935 
                 S-TIM1 
               
               
                 22 
                 1.15746 
                 0.0513 
               
               
                 23 
                 2.80595 
                 0.3177 
                 1.49700 
                 81.54 
                 0.53748 
                 S-FPL51 
               
               
                 24 
                 −0.64819 
                 0.1015 
                 1.84661 
                 23.78 
                 0.62072 
                 S-TIH53 
               
               
                 25 
                 −1.39929 
                 0.0069 
               
               
                 26 
                 −12.93548 
                 0.0860 
                 1.57099 
                 50.80 
                 0.55887 
                 S-BAL2 
               
               
                 27 
                 −3.31020 
                 0.3824 
               
               
                 28 
                 ∞ 
                 0.1674 
                 1.58913 
                 61.14 
                 0.54067 
                 S-BAL35 
               
               
                 29 
                 −1.46883 
                 0.8926 
               
               
                 30 
                 ∞ 
                 0.0794 
                 1.51633 
                 64.14 
                 0.53531 
                 S-BSL7 
               
               
                 31 
                 ∞ 
                 0.2612 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 14 
               
               
                   
               
               
                 Example 7/Specs (d-line) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Zoom Ratios 
                 1.0 
               
               
                   
                 f′ 
                 1.00 
               
               
                   
                 Bf′ 
                 1.21 
               
               
                   
                 FNo. 
                 1.90 
               
               
                   
                 2ω [°] 
                 58.6 
               
               
                   
                   
               
            
           
         
       
     
     Referring to Table 13 below, the Abbe number, the partial dispersion ratio, and the refractive index of each of the lenses which constitute the imaging lens of Example 7 will be described. 
     In the present Example, the Abbe number, the partial dispertion ratio, and the refractive index of each of the lenses which constitute the first lens group G 1  and the second lens group G 2  are the same as those in Example 1 except that the Abbe number vd 3 , the partial dispersion ratio θg,F 3 , and the refractive index Nd 3  of the third lens L 13  are respectively 25.42, 0.61616, and 1.80518; and the Abbe number vd 4 , the partial dispersion ratio θg,F 4 , and the refractive index Nd 4  of the fourth lens L 14  are respectively 42.73, 0.56486, and 1.83481. The values of the Abbe number vd 3  and the partial dispersion ratio θg,F 3  of the third lens L 13  satisfy the suitable numerical conditions with respect to the third lens described above, and the values of the Abbe number vd 4  and the partial dispersion ratio θg,F 4  of the fourth lens L 14  also satisfy the suitable numerical conditions with respect to the fourth lens described above. Therefore, the advantageous effects obtained by the values of these Abbe numbers and the partial dispersion ratios are also the same as those of Example 1. 
       FIG. 15  illustrates the respective aberration diagrams of the imaging lens of Example 7. 
     Table 15 shows the values of the conditions, of which the numerical ranges are defined by the conditional formulas (1) through (17) described above with respect to Examples 1 through 7. Note that a collection of the conditions, the numerical ranges of which are respectively defined by conditional formulas is shown below: conditional formula (1) defines vd 2 /vd 3 , conditional formula (2) defines FA/FB, conditional formula (3) defines f 1 /f, conditional formula (4) defines (RLF+RLB)/(RLF−RLB), conditional formula (5) defines (RL 2 F+RL 2 B)/(RL 2 F−RL 2 B), conditional formula (6) defines f 1234 /f, conditional formula (7) defines f 123 /f, conditional formula (8) defines FA/f, conditional formula (9) defines FB/f, conditional formula (10) defines (R 7 +R 8 )/(R 7 −R 8 ), conditional formula (11) defines D 6 /f, conditional formula (12) defines D 4 /f, conditional formula (13) defines f 1 /f 2 , conditional formula (14) defines L/f, conditional formula (15) defines Bf/f, conditional formula (16) defines (R 1 +R 2 )/(R 1 −R 2 ), and conditional formula (17) defines (R 9 +R 10 )/(R 9 −R 10 ). 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 15 
               
               
                   
               
               
                 Expression Numbers 
                 Conditional Formulas 
                 Example 1 
                 Example 2 
                 Example 3 
                 Example 4 
                 Example 5 
                 Example 6 
                 Example 7 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 (1) 
                 ν d2/ν d3 
                 3.43 
                 3.43 
                 3.43 
                 3.43 
                 3.43 
                 3.43 
                 3.21 
               
               
                 (2) 
                 FA/FB 
                 4.46 
                 3.14 
                 2.60 
                 3.33 
                 3.23 
                 3.34 
                 3.51 
               
               
                 (3) 
                 f1/f 
                 3.63 
                 3.77 
                 3.77 
                 3.78 
                 3.74 
                 3.77 
                 3.84 
               
               
                 (4) 
                 (RLF + RLB)/(RLF − RLB) 
                 1.00 
                 0.89 
                 0.67 
                 0.98 
                 1.01 
                 1.01 
                 1.00 
               
               
                 (5) 
                 (RL2F + RL2B)/(RL2F − RL2B) 
                 1.67 
                 −2.46 
                 −2.54 
                 1.76 
                 1.68 
                 1.69 
                 1.69 
               
               
                 (6) 
                 f1234/f 
                 −1.42 
                 −1.55 
                 −1.60 
                 −1.43 
                 −1.45 
                 −1.43 
                 −1.45 
               
               
                 (7) 
                 f123/f 
                 −0.85 
                 −0.88 
                 −0.88 
                 −0.85 
                 −0.84 
                 −0.84 
                 −0.86 
               
               
                 (8) 
                 FA/f 
                 7.69 
                 5.65 
                 4.78 
                 6.12 
                 5.90 
                 6.11 
                 6.38 
               
               
                 (9) 
                 FB/f 
                 1.73 
                 1.80 
                 1.84 
                 1.84 
                 1.83 
                 1.83 
                 1.82 
               
               
                 (10) 
                 (R7 + R8)/(R7 − R8) 
                 3.78 
                 3.49 
                 3.20 
                 3.72 
                 3.41 
                 3.43 
                 3.35 
               
               
                 (11) 
                 D6/f 
                 0.38 
                 0.32 
                 0.26 
                 0.33 
                 0.33 
                 0.33 
                 0.33 
               
               
                 (12) 
                 D4/f 
                 0.34 
                 0.32 
                 0.33 
                 0.33 
                 0.33 
                 0.34 
                 0.34 
               
               
                 (13) 
                 f1/f2 
                 −0.35 
                 −0.30 
                 −0.34 
                 −0.41 
                 −0.40 
                 −0.42 
                 −0.46 
               
               
                 (14) 
                 L/f 
                 5.16 
                 5.13 
                 5.15 
                 5.12 
                 5.13 
                 5.16 
                 5.15 
               
               
                 (15) 
                 Bf/f 
                 1.21 
                 1.19 
                 1.19 
                 1.20 
                 1.20 
                 1.21 
                 1.21 
               
               
                 (16) 
                 (R1 + R2)/(R1 − R2) 
                 −0.95 
                 −0.87 
                 −0.88 
                 −0.91 
                 −0.87 
                 −0.88 
                 −0.91 
               
               
                 (17) 
                 (R9 + R10)/(R9 − R10) 
                 −1.00 
                 −1.15 
                 −1.18 
                 −0.97 
                 −1.03 
                 −1.03 
                 −1.03 
               
               
                   
               
            
           
         
       
     
     Next, an imaging apparatus according to an embodiment of the present invention will be described.  FIG. 16  shows a schematic configuration of the imaging apparatus including the imaging lens of the embodiment of the present invention as an example of the imaging apparatus of the embodiment of the present invention. Note that  FIG. 16  schematically illustrates each of the lens groups. Examples of this imaging apparatus include a video camera or an electronic still camera, and the like, in which a solid state image sensor such as a CCD, a CMOS, and the like is applied as a recording medium. 
     The imaging apparatus  10  shown in  FIG. 16  includes an imaging lens  1 ; a filter  6 , which is disposed on the image side of the imaging lens  1  and which has a function of a low-pass filter or the like; an image sensor  7  disposed on the image side of the filter  6 ; and a signal processing circuit  8 . The image sensor  7  converts an optical image formed by the imaging lens  1  into an electric signal. A CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like may be employed as the image sensor  7 , for example. The image sensor  7  is disposed such that the imaging surface thereof matches the imaging plane of the imaging lens  1 . 
     An image photographed by the imaging lens  1  is formed on the imaging surface of the image sensor  7 , and an output signal regarding the image from the image sensor is subjected to an arithmetic processing by the signal processing circuit  8  so that an image is displayed on the display device  9 . 
     The present invention has been described with reference to the Embodiments and Examples. The present invention is not limited to the embodiments and the examples described above, and various modifications are possible. For example, values, such as the radius of curvature, the distances between surfaces, the refractive indices, the Abbe numbers, and the partial dispersion ratios of each lens can be changed as appropriate. 
     The imaging apparatus of the present invention is not also limited to the configuration described above, and various modifications are possible.