Abstract:
A zoom lens system having a negative first lens group and a positive second lens group, from an object side, and achieving zooming by varying a group-to-group distance. The second lens group includes a three-element cemented lens which is a set of three lens elements cemented together including, from the object side, a negative first lens, a positive second lens, and a negative third lens, and the three-element cemented lens fulfills conditional formulas 0.08&lt;(rs2+rs1)/(rs2−rs1)&lt;0.5, 27&lt;v2-v1&lt;40, 20&lt;v2-v3&lt;38 (rs1, rs2 represent the curvature radius of the sides of cemented surfaces of the three-element cemented lens on the object side and the image side respectively, and v1-3 represent the Abbe numbers of the first to third lenses of the three-element cemented lens).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a zoom lens system, an imaging optical device, and a digital appliance. More particularly, the present invention relates to a compact zoom lens system suitable for a digital camera which captures an image of a subject by means of an image sensor; an imaging optical device which outputs, in the form of an electrical signal, an image of a subject captured by such a zoom lens system and an image sensor; and a digital appliance, such as a digital camera, furnished with an image input function through incorporation of such an imaging optical device. 
       BACKGROUND ART  
       [0002]    Conventionally, many zoom lens systems have been proposed that comprise two, i.e., a negative and a positive, lens groups. For example, Patent Document 1 identified below proposes a zoom lens system wherein a second lens group is composed of a front group and a rear group and the front group is used as a focusing group to achieve compactness. Inconveniently, however, the zoom lens system proposed in Patent Document 1 produces large curvature of field at the periphery of the image field, and produces large chromatic coma. 
       LIST OF CITATIONS 
     Patent Literature 
       [0003]    Patent Document 1: JP-A-2001-330774 
       SUMMARY OF THE INVENTION 
       [0004]    Problem to be Solved by the Invention 
         [0005]    The recent digitalization has made it possible for the user to see a shot image to all its corners in its actual size on a monitor. This has brought demand for high MTF (modulation transfer function) performance, not only around the axis but up to the periphery, in combination with reduced chromatic aberration. However, coping with digitalization requires, for reasons related to the design of a CCD (charge-coupled device), a longer distance to the exit pupil position. This tends to lead to an increased total length, making it difficult to achieve high performance and compactness simultaneously, as in the case of the zoom lens system proposed in Patent Document 1. 
         [0006]    Against the background discussed above, an object of the present invention is to provide a zoom lens system, and an imaging optical device and a digital appliance provided with it as well, that is compact but that nevertheless has satisfactorily corrected curvature of field from axis to periphery over the entire zoom range combined with reduced chromatic aberration of curvature of field and reduced chromatic coma. 
       Means for Solving the Problem 
       [0007]    To achieve the above object, according to a first aspect of the present invention, a zoom lens system is provided with, from the object side, a first lens group having a negative optical power and a second lens group having a positive optical power, and achieves zooming by varying the group-to-group distance. Here, the second lens group includes at least one three-element cemented lens which is a set of three lens elements cemented together including, from the object side, a first lens element having a negative optical power, a second lens element having a positive optical power, and a third lens element having a negative optical power. Moreover, the three-element cemented lens fulfills conditional formulas (1) to (3) below: 
         [0000]      0.08=( rs 2+ rs 1)/( rs 2 −rs 1)&lt;0.5   (1)
 
         [0000]      27 &lt;v 2− v 1&lt;40   (2)
 
         [0000]      20 &lt;v 2 −v 3&lt;38   (3)
 
         [0000]    where
       rs1 represents the radius of curvature of the object-side cemented surface of the three-element cemented lens;   rs2 represents the radius of curvature of the image-side cemented surface of the three-element cemented lens;   v1 represents the Abbe number of the first lens element of the three-element cemented lens;   v2 represents the Abbe number of the second lens element of the three-element cemented lens;   v3 represents the Abbe number of the third lens element of the three-element cemented lens.       
 
         [0013]    According to a second aspect of the present invention, in the above-described zoom lens system according to the first aspect, the first and second lens groups fulfill conditional formula (4) below: 
         [0000]      −0.8&lt; f 1 /f 2&lt;−0.5   (4)
 
         [0000]    where
       f1 represents the focal length of the first lens group; and   f2 represents the focal length of the second lens group.       
 
         [0016]    According to a third aspect of the present invention, in the above-described zoom lens system according to the first or second aspect, the second lens group includes, from the object side, a front group, an aperture stop, and a rear group; includes the three-element cemented lens in the rear group; and fulfills conditional formula (5) below: 
         [0000]      −1 &lt;fs/f 2 —   r&lt;− 0.3   (5)
 
         [0000]    where
       f2_r represents the focal length of the rear group of the second lens group; and   fs represents the focal length of the three-element cemented lens in the second lens group.       
 
         [0019]    According to a fourth aspect of the present invention, in the above-described zoom lens system according to any of the first to third aspects, the first lens group includes two composite aspherical surfaces that fulfill conditional formula (6) below: 
         [0000]      4.8&lt; ΔX _max/Δ X _min&lt;6.0   (6)
       where, with respect to the thickness, in the optical axis direction, of the resin forming the composite aspherical surfaces,   ΔX_max represents the maximum resin thickness; and   ΔX_min represents the minimum resin thickness.       
 
         [0023]    According to a fifth aspect of the present invention, in the above-described zoom lens system according to any of the first to fourth aspects, the second lens group includes, from the object side, a front group, an aperture stop, and a rear group, and the rear group includes three lens components comprising a positive, a negative, and a positive lens component which are each a single or cemented lens element. 
         [0024]    According to a sixth aspect of the present invention, an imaging optical device is provided with the above-described zoom lens system according to any one of the first to fifth aspects; and an image sensor for converting an optical image formed on a light-receiving surface into an electrical signal. Here, the zoom lens system is arranged such that an optical image of a subject is formed on the light-receiving surface of the image sensor. 
         [0025]    According to a seventh aspect of the present invention, a digital appliance is provided with the above-described imaging optical device according to the sixth aspect so as to have at least one of a function of shooting a still image of the subject or a function of shooting a moving image of the subject. 
       ADVANTAGEOUS EFFECTS OF THE INVENTION 
       [0026]    According to the present invention, owing to the arrangement of a three-element cemented lens fulfilling predetermined conditions in the second lens group in a two-group zoom type, it is possible to obtain a high-performance zoom lens system, and hence a high-performance imaging optical device, that is compact but that nevertheless has satisfactorily corrected curvature of field from axis to periphery over the entire zoom range combined with reduced chromatic aberration of curvature of field and reduced chromatic coma. Using such a compact high-performance zoom lens system or imaging optical device in a digital appliance (for example, a digital camera) makes it possible to add a high-performance image input function to the digital appliance in a compact fashion. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0027]      FIG. 1  is an optical construction diagram of the first embodiment (Example 1); 
           [0028]      FIG. 2  is an optical construction diagram of the second embodiment (Example 2); 
           [0029]      FIG. 3  is an optical construction diagram of the third embodiment (Example 3); 
           [0030]      FIG. 4  is an optical construction diagram of the fourth embodiment (Example 4); 
           [0031]      FIG. 5  is an optical construction diagram of the fifth embodiment (Example 5); 
           [0032]      FIG. 6  is an optical construction diagram of the sixth embodiment (Example 6); 
           [0033]      FIGS. 7A to 7I  are longitudinal aberration diagrams of Example 1; 
           [0034]      FIGS. 8A to 8I  are longitudinal aberration diagrams of Example 2; 
           [0035]      FIGS. 9A to 9I  are longitudinal aberration diagrams of Example 3; 
           [0036]      FIGS. 10A to 10I  are longitudinal aberration diagrams of Example 4; 
           [0037]      FIGS. 11A to 11I  are longitudinal aberration diagrams of Example 5; 
           [0038]      FIGS. 12A to 12I  are longitudinal aberration diagrams of Example 6; 
           [0039]      FIGS. 13A to 13C  are aberration diagrams showing chromatic aberration of curvature of field in Example 1; 
           [0040]      FIGS. 14A to 14C  are aberration diagrams showing chromatic aberration of curvature of field in Example 2; 
           [0041]      FIGS. 15A to 15C  are aberration diagrams showing chromatic aberration of curvature of field in Example  3 ; 
           [0042]      FIGS. 16A to 16C  are aberration diagrams showing chromatic aberration of curvature of field in Example 4; 
           [0043]      FIGS. 17A to 17C  are aberration diagrams showing chromatic aberration of curvature of field in Example 5; 
           [0044]      FIGS. 18A to 18C  are aberration diagrams showing chromatic aberration of curvature of field in Example 6; 
           [0045]      FIGS. 19A to 19J  are lateral aberration diagrams showing chromatic coma at the wide-angle end in Example 1; 
           [0046]      FIGS. 20A to 20I  are lateral aberration diagrams showing chromatic coma at the mid-focal-length position in Example 1; 
           [0047]      FIGS. 21A to 21J  are lateral aberration diagrams showing chromatic coma at the telephoto end in Example 1; 
           [0048]      FIGS. 22A to 22J  are lateral aberration diagrams showing chromatic coma at the wide-angle end in Example 2; 
           [0049]      FIGS. 23A to 23J  are lateral aberration diagrams showing chromatic coma at the mid-focal-length position in Example 2; 
           [0050]      FIGS. 24A to 24J  are lateral aberration diagrams showing chromatic coma at the telephoto end in Example 2; 
           [0051]      FIGS. 25A to 25J  are lateral aberration diagrams showing chromatic coma at the wide-angle end in Example 3; 
           [0052]      FIGS. 26A to 26J  are lateral aberration diagrams showing chromatic coma at the mid-focal-length position in Example 3; 
           [0053]      FIGS. 27A to 27J  are lateral aberration diagrams showing chromatic coma at the telephoto end in Example 3; 
           [0054]      FIGS. 28A to 28J  are lateral aberration diagrams showing chromatic coma at the wide-angle end in Example 4; 
           [0055]      FIGS. 29A to 29J  are lateral aberration diagrams showing chromatic coma at the mid-focal-length position in Example 4; 
           [0056]      FIGS. 30A to 30J  are lateral aberration diagrams showing chromatic coma at the telephoto end in Example 4; 
           [0057]      FIGS. 31A to 31J  are lateral aberration diagrams showing chromatic coma at the wide-angle end in Example 5; 
           [0058]      FIGS. 32A to 32J  are lateral aberration diagrams showing chromatic coma at the mid-focal-length position in Example 5; 
           [0059]      FIGS. 33A to 33J  are lateral aberration diagrams showing chromatic coma at the telephoto end in Example 5; 
           [0060]      FIGS. 34A to 34J  are lateral aberration diagrams showing chromatic coma at the wide-angle end in Example 6; 
           [0061]      FIGS. 35A to 35J  are lateral aberration diagrams showing chromatic coma at the mid-focal-length position in Example 6; 
           [0062]      FIGS. 36A to 36J  are lateral aberration diagrams showing chromatic coma at the telephoto end in Example 6; and 
           [0063]      FIG. 37  is a schematic diagram showing an example of a configuration, in outline, of a digital appliance incorporating a zoom lens system. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0064]    Hereinafter, a zoom lens system, an imaging optical device, and a digital appliance according to the present invention will be described. A zoom lens system according to the present invention is a zoom lens system that is composed of from the object side, a first lens group having a negative optical power and a second lens group having a positive optical power (an optical power is a quantity defined as the reciprocal of a focal length) and that achieves zooming by varying the group-to-group distance. The second lens group includes at least one three-element cemented lens, i.e., a set of three lens elements cemented together, composed of, from the object side, a first lens element having a negative optical power, a second lens element having a positive optical power, and a third lens element having a negative optical power. The three-element cemented lens fulfills conditional formulae (1) to (3) below. 
         [0000]      0.08=( rs 2+ rs 1)/( rs 2 −rs 1)&lt;0.5   (1)
 
         [0000]      27 &lt;v 2− v 1&lt;40   (2)
 
         [0000]      20 &lt;v 2 −v 3&lt;38   (3)
 
         [0000]    where
       rs1 represents the radius of curvature of the object-side cemented surface of the three-element cemented lens;   rs2 represents the radius of curvature of the image-side cemented surface of the three-element cemented lens;   v1 represents the Abbe number of the first lens element of the three-element cemented lens;   v2 represents the Abbe number of the second lens element of the three-element cemented lens;   v3 represents the Abbe number of the third lens element of the three-element cemented lens.       
 
         [0070]    As mentioned earlier, digitalization has made it possible for the user to see a shot image in its actual size on a monitor, and this has brought demand for improved MTF performance and reduced chromatic aberration. However, coping with digitalization requires that the exit pupil position be located far away from the image surface, and this leads to an increased total length, making it difficult to achieve high performance and compactness simultaneously. Adopting the above construction helps achieve high performance, from axis to periphery, and compactness simultaneously. For example, by composing the second lens group out of a front group, an aperture stop, and a rear group and arranging a negative-positive-negative three-element cemented lens in the rear group of the second lens group, it is possible to satisfactorily correct, from the wide-angle end to the telephoto end, the astigmatism and chromatic aberration that occur in the rear group of the second lens group. 
         [0071]    Conditional formula (1) defines a preferred shape factor of the second lens element having a positive optical power in the three-element cemented lens. Fulfilling formula (1) makes it possible to obtain an optical solution with small curvature of field from the wide-angle end to the telephoto end. A shape beyond the upper limit of formula (1) results in the image-side cemented surface having a smaller absolute value for its curvature than the object-side cemented surface, and causes large curvature of field on the over side at the telephoto end, which is undesirable. A shape beneath the lower limit of formula (1) results in the object-side and image-side cemented surfaces having close absolute values for their curvature, and causes large curvature of field at the wide-angle end, which is undesirable. 
         [0072]    Conditional formula (2) defines a preferred dispersion difference between the first and second lens elements of the three-element cemented lens, and formula (3) defines a preferred dispersion difference between the second and third lens elements of the three-element cemented lens. Fulfilling conditional formulae (2) and (3) gives an optical solution that allows correction of chromatic curvature of field and chromatic coma over the entire zoom range. Above the upper limit of formula (2) or (3), the dispersion difference among the individual lens elements of the three-element cemented lens is so large that the three-element cemented lens produces large chromatic aberration of curvature of field, which is undesirable. Below the lower limit of formula (2) or (3), the dispersion difference among the individual lens elements of the three-element cemented lens is so small that the three-element cemented lens produces large chromatic coma, in particular chromatic coma on the upper side at the wide-angle end, which is undesirable. 
         [0073]    With the distinctive construction described above, owing to the arrangement of a three-element cemented lens fulfilling predetermined conditions in the second lens group in a two-group zoom type, it is possible to obtain a high-performance zoom lens system, and hence a high-performance imaging optical device, that is compact but that nevertheless has satisfactorily corrected curvature of field from axis to periphery over the entire zoom range from the wide-angle end to the telephoto end combined with reduced chromatic aberration of curvature of field and reduced chromatic coma. Using such a compact high-performance zoom lens system or imaging optical device in a digital appliance such as a digital camera makes it possible to add a high-performance image input function to the digital appliance in a compact fashion, contributing to making the digital appliance compact, low-cost, high-performance, versatile, etc. For example, a zoom lens system according to the present invention is suitable as an interchangeable lens for an interchangeable-lens digital camera, and thus helps obtain a compact, light-weight interchangeable lens convenient to carry. Conditions and other features for obtaining those effects with a good balance, and for achieving higher optical performance, further compactness, etc., will now be described. 
         [0074]    It is particularly preferable that a zoom lens system according to the present invention fulfill formula (1a) below. 
         [0000]      0.08&lt;( rs 2 +rs 1)/( rs 2− rs 1)&lt;0.40   (1a)
 
         [0075]    Conditional formula (1a) defines a conditional range, within the conditional range defined by formula (1) noted previously, that is particularly preferable from the above-mentioned and other viewpoints. Accordingly, preferably, fulfilling formula (1a) helps augment the above-mentioned effects. 
         [0076]    It is particularly preferable that a zoom lens system according to the present invention fulfill formula (2a) below. 
         [0000]      30 &lt;v 2− v 1&lt;40   (2a)
 
         [0077]    Conditional formula (2a) defines a conditional range, within the conditional range defined by formula (2) noted previously, that is particularly preferable from the above-mentioned and other viewpoints. Accordingly, preferably, fulfilling formula (2a) helps augment the above-mentioned effects. 
         [0078]    It is particularly preferable that a zoom lens system according to the present invention fulfill formula (3a) below. 
         [0000]      25&lt; v 2 −v 3&lt;38   (3a)
 
         [0079]    Conditional formula (3a) defines a conditional range, within the conditional range defined by formula (3) noted previously, that is particularly preferable from the above-mentioned and other viewpoints. Accordingly, preferably, fulfilling formula (3a) helps augment the above-mentioned effects. 
         [0080]    It is preferable that the first and second lens groups fulfill conditional formula (4) below. 
         [0000]      −0.8&lt; f 1 /f 2&lt;−0.5   (4)
 
         [0000]    where
       f1 represents the focal length of the first lens group; and   f2 represents the focal length of the second lens group.       
 
         [0083]    Fulfilling conditional formula (4) gives the first and second lens groups adequate optical powers, and this helps suppress an increase in the movement amount of the first lens group, contributing to achieving compactness. Above the upper limit of conditional formula (4), the optical power of the first lens group is high, and this helps achieve compactness; however, an increased optical power in the first lens group invites an increased optical power in the second lens group, and this makes it difficult to correct aberrations, in particular spherical aberration and coma at the telephoto end, making it difficult to obtain high performance. Below the lower limit of conditional formula (4), the optical power of the first lens group is low, and this increases the movement amount of the first lens group, resulting in an increased total length, making it difficult to achieve compactness. 
         [0084]    It is particularly preferable that a zoom lens system according to the present invention fulfill formula (4a) below. 
         [0000]      −0.72 &lt;f 1 /f 2&lt;−0.6   (4a)
 
         [0085]    Conditional formula (4a) defines a conditional range, within the conditional range defined by formula (4) noted previously, that is particularly preferable from the above-mentioned and other viewpoints. Accordingly, preferably, fulfilling formula (4a) helps augment the above-mentioned effects. 
         [0086]    It is preferable that the second lens group be composed of, from the object side, a front group, an aperture stop, and a rear group, include the three-element cemented lens in the rear group, and fulfill conditional formula (5) below. 
         [0000]      −1 &lt;fs/f 2 —   r&lt;− 0.3&lt;  (5)
 
         [0000]    where
       f2_r represents the focal length of the rear group of the second lens group; and   fs represents the focal length of the three-element cemented lens in the second lens group.       
 
         [0089]    It is preferable to divide the second lens group into a front group and a rear group by an aperture stop, to include the three-element cemented lens in the rear group, and to fulfill conditional formula (5). Fulfilling conditional formula (5) helps optimize the optical power relationship between the rear group of the second lens group and the three-element cemented lens, and this helps effectively suppress the coma and spherical aberration that occur in the rear group of the second lens group. Above the upper limit of conditional formula (5), the negative optical power of three-element cemented lens is high, making it difficult to correct aberrations (in particular, spherical aberration) at the telephoto end. Below the lower limit of conditional formula (5), the negative optical power of three-element cemented lens is low, inviting increased lens diameters on the image-side of the aperture stop. 
         [0090]    It is preferable that the first lens group include two composite aspherical surfaces that fulfill conditional formula (6) below. 
         [0000]      4.8 &lt;ΔX _max/Δ X   min &lt;6.0   (6)
 
         [0000]    where, with respect to the thickness, in the optical axis direction, of the resin forming the composite aspherical surfaces,
       ΔX_max represents the maximum resin thickness; and   ΔX_min represents the minimum resin thickness.       
 
         [0093]    Providing two composite aspherical surfaces as described above in the first lens group helps effectively suppress the distortion and curvature of field that occur in the first lens group. In this zoom type, correcting the negative distortion that occurs in the first lens group requires an aspherical surface, and adding another aspherical surface to effectively correct curvature of field from the wide-angle end to the telephoto end makes effective correction possible. 
         [0094]    Fulfilling conditional formula (6) makes it possible to satisfactorily correct the curvature of field that occurs in the first lens group. Below the lower limit of the conditional formula (6), the difference in resin thickness is small, causing large curvature of field at the wide-angle end, which is undesirable. Above the upper limit of conditional formula (6), the difference in resin thickness is large, causing large curvature of field at the telephoto end, which is undesirable. 
         [0095]    It is preferable that the second lens group be composed of, from the object side, a front group, an aperture stop, and a rear group, and that the rear group be composed of three lens components, namely a positive, a negative, and a positive lens component which are each a single or cemented lens element. Composing the rear group of the second lens group out of a positive, a negative, and a positive lens component is preferable for satisfactory correction of aberrations over the entire zoom range. In addition, using a three-element cemented lens as mentioned above as the negative lens component in the rear group makes it possible to satisfactorily correct chromatic aberration and curvature of field over the entire zoom range and to reduce spherical aberration and coma over the entire zoom range. 
         [0096]    A zoom lens system according to the present invention is suitable for use as an imaging lens in a digital appliance (for example, a digital camera) furnished with an image input function, and can be combined with an image sensor or the like to build an imaging optical device that optically takes in an image of a subject and outputs it in the form of an electrical signal. An imaging optical device is an optical device that constitutes a main component of a camera used to shoot still and moving images of a subject, and is composed of, for example, from the object side (i.e., subject side), a zoom lens system for forming an optical image of an object and an image sensor for converting the optical image formed by the zoom lens system into an electrical signal. By arranging the zoom lens system having the distinctive construction described previously in such a way that the optical image of the subject is formed on the light-receiving surface (i.e., imaging surface) of the image sensor, it is possible to obtain an imaging optical device, and hence a digital appliance provided with it, that is compact, low-cost, and high-performance. 
         [0097]    Examples of digital appliances furnished with an image input function include: digital cameras, video cameras, surveillance cameras, vehicle-mounted cameras, and cameras for videophones. Also included are personal computers, portable digital appliances (for example, cellular telephones, smartphones, and mobile computers), peripheral devices for those (such as canners and printers), and other digital appliances or the like furnished with a camera function by incorporation or optional attachment. As will be understood from these examples, not only an imaging optical device can be used to build a camera, but also an imaging optical device can be incorporated in various appliances to add a camera function to them. For example, it is possible to build a digital appliance furnished with an image input function, such as a camera-equipped cellular telephone. 
         [0098]      FIG. 37  is a schematic sectional view showing an example of the configuration, in outline, of a digital appliance DU incorporating a zoom lens system ZL, as an example of a digital appliance furnished with an image input function. An imaging optical device LU incorporated in the digital appliance DU shown in  FIG. 37  includes, from the object side (i.e., subject side), a zoom lens system ZL (with AX representing the optical axis) for zoomably forming an optical image (image surface) IM of an object, an plane-parallel plate PT (corresponding to the cover glass of an image sensor SR and, wherever applicable, optical filters and the like, such as an optical low-pass filter and an infrared cut filter, arranged as necessary), and an image sensor SR for converting the optical image IM formed on the light-receiving surface (imaging surface) SS by the zoom lens system ZL into an electrical signal. When this imaging optical device LU is used to build a digital appliance DU, the former is typically arranged inside the body of the latter; to realize a camera function, any configuration can be adopted that suits the needs. For example, an imaging optical device LU built as a unit can be configured freely removable from or rotatable relative to the body of the digital appliance DU. 
         [0099]    The zoom lens system ZL has a two-group zoom construction composed of two groups, namely a negative and a positive group, and is so configured that zooming (magnification variation) is achieved as a result of the first and second lens groups moving individually along the optical axis AX so as to vary the group-to-group distance, that focusing is achieved as a result of the front group in the second lens group moving along the optical axis AX (focusing toward a close object is achieved as a result of the front group moving toward the image side), and that an optical image IM is formed on the light-receiving surface SS of the image sensor SR. 
         [0100]    Used as the image sensor SR is, for example, a solid-state image sensor such as a CCD (charge-coupled device) image sensor or a CMOS (complementary metal-oxide semiconductor) image sensor having a plurality of pixels. The zoom lens system ZL is arranged such that an optical image IM of a subject is formed on the light-receiving surface SS, which is the photoelectric conversion portion of the image sensor SR, and thus the optical image IM formed by the zoom lens system ZL is converted into an electrical signal by the image sensor SR. 
         [0101]    The digital appliance DU includes, in addition to the imaging optical device LU, a signal processing portion  1 , a control portion  2 , a memory  3 , an operation portion  4 , a display portion  5 , etc. The signal generated by the image sensor SR is subjected to predetermined processing such as digital image processing and image compression processing in the signal processing portion  1 , and is then recorded, as a digital video signal, in the memory  3  (a semiconductor memory, an optical disc, or the like) or, in some cases, transmitted to another appliance (for example, a communication function of a cellular telephone) via a cable or after being converted into an infrared signal or the like. The control portion  2  comprises a microprocessor, and performs, in a centralized fashion, control of functions such as image shooting functions (still image shooting function, moving image shooting function, etc.) and image playback functions; and control of lens movement mechanisms for zooming, focusing, camera shake correction, etc. For example, the control portion  2  controls the imaging optical device LU to perform at least either still image shooting or moving image shooting with respect to a subject. The display portion  5  comprises a display device such as a liquid crystal monitor, and displays images based on the image signal resulting from conversion by the image sensor SR or based on image data recorded in the memory  3 . The operation portion  4  comprises operation members such as operation buttons (for example, a shutter release button), operation dials (for example, a shooting mode dial), etc., and conveys to the control portion  2  the data entered through operation by the user. 
         [0102]    Now, by way of a first to a sixth embodiment, specific optical constructions of the zoom lens system ZL will be described in more detail.  FIGS. 1 to 6  are optical construction diagrams corresponding to the zoom lens system ZL in the first to sixth embodiments respectively, and show, in an optical section, the lens arrangement, lens shapes, etc. at each of the wide-angle end (W), the mid-focal-length position (M), and the telephoto end (T). In each optical construction diagram, arrows m 1  and m 2  schematically indicate the movement of the first lens group Gr 1  and the second lens group Gr 2 , respectively, during zooming. As arrows m 1  and m 2  indicate, the first lens group Gr 1 , during zooming from the wide-angle end (W) to the telephoto end (T), takes a U-turn course, moving first toward the image surface IM and then back toward the object side; the second lens group Gr 2 , during zooming from the wide-angle end (W) to the telephoto end (T), moves toward the object side. 
         [0103]    An aperture stop ST is located in the second lens group Gr 2 , and moves together with the second lens group Gr 2  during zooming. The second lens group Gr 2  is composed of, from the object side, a front group GrF, an aperture stop ST, and a rear group GrR, and the rear group GrR is composed of three lens components, namely a positive, a negative, and a positive lens component, which are each a single or cemented lens element. Of these three lens component, the negative lens component is composed of, from the object side, a three-element cemented lens made up of a first lens element L 1  having a negative optical power, a second lens element L 2  having a positive optical power, and a third lens element L 3  having a negative optical power. The front group GrF is a focusing group, and moves toward the image side for focusing on a close object as indicated by broken-line arrow mF. 
         [0104]    In the first embodiment ( FIG. 1 ), each lens group is composed, from the object side, as follows. The first lens group Gr 1  is composed of a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, and a biconvex lens element. The front group GrF of the second lens group Gr 2  is composed of a cemented lens element made up of a negative meniscus lens element having a convex surface on the object side and a biconvex lens element. The rear group GrR of the second lens group Gr 2  is composed of a cemented lens element made up of a biconvex lens element and a biconcave lens element, a three-element cemented lens LS made up of a negative meniscus lens element (first lens element L 1 ) having a convex surface on the object side, a biconvex lens element (second lens element L 2 ), and a biconcave lens element (third lens element L 3 ), and a biconvex lens element. In this zoom lens system ZL, the object-side surface of the second lens element from the object side, the image-side surface of the third lens element from the object side, and both surfaces of the biconvex lens element arranged at the most image-side position are aspherical surfaces, and the aspherical surfaces in the first lens group Gr 1  are both composite aspherical surfaces. 
         [0105]    In the second embodiment ( FIG. 2 ), each lens group is composed, from the object side, as follows. The first lens group Gr 1  is composed of a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, and a biconvex lens element. The front group GrF of the second lens group Gr 2  is composed of a cemented lens element made up of a negative meniscus lens element having a convex surface on the object side and a positive meniscus lens element having a convex surface on the object side. The rear group GrR of the second lens group Gr 2  is composed of a cemented lens element made up of a biconvex lens element and a negative meniscus lens element having a convex surface on the image side, a three-element cemented lens LS made up of a negative meniscus lens element (first lens element L 1 ) having a convex surface on the object side, a biconvex lens element (second lens element L 2 ), and a biconcave lens element (third lens element L 3 ), and a biconvex lens element. In this zoom lens system ZL, the object-side surface of the second lens element from the object side, the image-side surface of the third lens element from the object side, and both surfaces of the biconvex lens element arranged at the most image-side position are aspherical surfaces, and the aspherical surfaces in the first lens group Gr 1  are both composite aspherical surfaces. 
         [0106]    In the third embodiment ( FIG. 3 ), each lens group is composed, from the object side, as follows. The first lens group Gr 1  is composed of a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, and a biconvex lens element. The front group GrF of the second lens group Gr 2  is composed of a cemented lens element made up of a negative meniscus lens element having a convex surface on the object side and a positive meniscus lens element having a convex surface on the object side. The rear group GrR of the second lens group Gr 2  is composed of a cemented lens element made up of a biconvex lens element and a negative meniscus lens element having a convex surface on the image side, a three-element cemented lens LS made up of a negative meniscus lens element (first lens element L 1 ) having a convex surface on the object side, a biconvex lens element (second lens element L 2 ), and a biconcave lens element (third lens element L 3 ), and a biconvex lens element. In this zoom lens system ZL, the object-side surface of the second lens element from the object side, the image-side surface of the third lens element from the object side, and both surfaces of the biconvex lens element arranged at the most image-side position are aspherical surfaces, and the aspherical surfaces in the first lens gaup Gr 1  are both composite aspherical surfaces. 
         [0107]    In the fourth embodiment ( FIG. 4 ), each lens group is composed, from the object side, as follows. The first lens group Gr 1  is composed of a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, and a biconvex lens element. The front group GrF of the second lens group Gr 2  is composed of a cemented lens element made up of a negative meniscus lens element having a convex surface on the object side and a biconvex lens element. The rear group GrR of the second lens group Gr 2  is composed of a cemented lens element made up of a biconvex lens element and a negative meniscus lens element having a convex surface on the image side, a three-element cemented lens LS made up of a negative meniscus lens element (first lens element L 1 ) having a convex surface on the object side, a biconvex lens element (second lens element L 2 ), and a biconcave lens element (third lens element L 3 ), and a biconvex lens element. In this zoom lens system ZL, the object-side surface of the second lens element from the object side, the image-side surface of the third lens element from the object side, and both surfaces of the biconvex lens element arranged at the most image-side position are aspherical surfaces, and the aspherical surfaces in the first lens group Gr 1  are both composite aspherical surfaces. 
         [0108]    In the fifth embodiment ( FIG. 5 ), each lens group is composed, from the object side, as follows. The first lens group Gr 1  is composed of a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, and a biconvex lens element. The front group GrF of the second lens group Gr 2  is composed of a cemented lens element made up of a negative meniscus lens element having a convex surface on the object side and a biconvex lens element. The rear group GrR of the second lens group Gr 2  is composed of a cemented lens element made up of a biconvex lens element and a negative meniscus lens element having a convex surface on the image side, a three-element cemented lens LS made up of a negative meniscus lens element (first lens element L 1 ) having a convex surface on the object side, a biconvex lens element (second lens element L 2 ), and a biconcave lens element (third lens element L 3 ), and a biconvex lens element. In this zoom lens system ZL, the object-side surface of the second lens element from the object side, the image-side surface of the third lens element from the object side, and both surfaces of the biconvex lens element arranged at the most image-side position are aspherical surfaces, and the aspherical surfaces in the first lens group On are both composite aspherical surfaces. 
         [0109]    In the sixth embodiment ( FIG. 6 ), each lens group is composed, from the object side, as follows. The first lens group Gr 1  is composed of a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, and a biconvex lens element. The front group GrF of the second lens group Gr 2  is composed of a cemented lens element made up of a negative meniscus lens element having a convex surface on the object side and a biconvex lens element. The rear group GrR of the second lens group Gr 2  is composed of a cemented lens element made up of a biconvex lens element and a negative meniscus lens element having a convex surface on the image side, a three-element cemented lens LS made up of a negative meniscus lens element (first lens element L 1 ) having a convex surface on the object side, a biconvex lens element (second lens element L 2 ), and a biconcave lens element (third lens element L 3 ), and a biconvex lens element. In this zoom lens system ZL, the object-side surface of the second lens element from the object side, the image-side surface of the third lens element from the object side, and both surfaces of the biconvex lens element arranged at the most image-side position are aspherical surfaces, and the aspherical surfaces in the first lens group Gr 1  are both composite aspherical surfaces. 
       EXAMPLES 
       [0110]    Hereinafter, the construction and other features of zoom lens systems embodying the present invention will be described more specifically with reference to the construction data of practical examples. Examples 1 to 6 (EX1 to EX6) presented below are numerical practical examples corresponding respectively to the first to sixth embodiments described above, and the optical construction diagrams ( FIGS. 1 to 6 ) showing the first to sixth embodiments also show the lens arrangement, lens shapes, etc. of the corresponding ones of Examples 1 to 6. 
         [0111]    In the construction data of each practical example, listed as surface data are, from left to right, surface number, radius of curvature r (mm), axial surface-to-surface distance d (mm), refractive index nd for the d-line (with a wavelength of 587.56 nm), and Abbe number vd for the d-line. A surface whose surface number is marked with an asterisk “*” is an aspherical surface, and its surface shape is defined by formula (AS) below in a local rectangular coordinate system (x, y, z) having an origin at the vertex of the surface. Listed as aspherical surface data are aspherical surface coefficients etc. It should be noted that, in the aspherical surface data of each practical example, any term that does not appear there has a coefficient “0,” and that, for all the data, “E-n” stands for “×10 −t1 .” 
         [0000]        z =( c·h   2 )/[1+√{1−(1+ K )· c   2   ·h   2 }]+Σ( Aj·h   j )   (AS)
 
         [0000]    where
       h represents the height in a direction perpendicular to the z-axis (optical axis AX) (h 2 =x 2 +y 2 );   z represents the amount of sag (with respect to the vertex of the surface) in the optical axis AX direction at the height h;   c represents the curvature at the vertex of the surface (the reciprocal of the radius of curvature r);   K represents a conic constant; and   Aj represents the aspherical surface coefficient of order j.       
 
         [0117]    Listed as miscellaneous data are zoom ratio (magnification variation ratio) and, for each of the focal length positions W, M, and T, focal length (f, mm) of the entire system, whole angle of view (2ω, °), back focus (BF, mm), total lens length (TL, mm), f-number (Fno), image height (Y′, mm), and variable surface-to-surface distances di (where i is a surface number, mm). Listed as focal lengths of lens groups etc. are the focal lengths (f1, f2, fs, f2_r, etc.; mm) of the lens groups etc. (the first lens group Gr 1 , the second lens group Gr 2 , the front group GrF, the rear group GrR, the three-element cemented lens LS, the first lens element L 1 , the second lens element L 2 , and the third lens element L 3 ). Here, back focus BF denotes the distance from the image-side surface of the plane-parallel plate PT to the image surface IM, and lens total length TL denotes the distance from the foremost lens surface to the image surface IM. Table 1 lists the values corresponding to the conditional formulae as observed in each practical example. 
         [0118]      FIGS. 7A-7I  to  12 A- 12 I are longitudinal aberration diagrams corresponding to Examples 1 to 6 (EX1 to EX6), respectively, with respect to a subject at infinity, each showing, at  FIGS. 7A-7C  to  12 A- 12 C, aberrations at the wide-angle end (W); at  7 D- 7 F to  12 D- 12 F, aberrations at the mid-focal-length position (M); and at  7 G- 7 I to  12 G- 12 I, aberrations at the telephoto end (T).  FIGS. 7A to 12A ,  7 D to  12 D, and  7 G to  12 G are spherical aberration diagrams.  FIGS. 7B to 12B ,  7 E to  12 E, and  7 H to  12 H are astigmatism diagrams.  FIGS. 7C to 12C ,  7 F to  12 F, and  7 I to  12 I are distortion diagrams. In the spherical aberration diagrams, a solid line indicates the amount of spherical aberration for the d-line (with a wavelength of 587.56 nm) in terms of the amount of deviation (unit: mm) in the optical axis AX direction from the paraxial image surface, the vertical axis representing the height of incidence at the pupil as normalized with respect to the maximum height there (i.e., the relative height at the pupil). In the astigmatism diagrams, a broken line T indicates the tangential image surface for the d-line, and a solid line S indicates the sagittal image surface for the d-line, each in terms of the amount of deviation (unit: mm) in the optical axis AX direction from the paraxial image surface, the vertical axis representing the image height (IMG HT, unit: mm). In the distortion diagrams, the horizontal axis represents the distortion (unit; %) for the d-line, and the vertical axis represents the image height (IMG HT, unit: mm). The maximum value of the image height IMG HT corresponds to the maximum image height on the image surface IM (one-half of the diagonal length of the light-receiving surface SS of the image sensor SR). 
         [0119]      FIGS. 13A-13C  to  18 A- 18 C are chromatic curvature-of-field diagrams corresponding to Examples 1 to 6 (EX1 to EX6) respectively, each showing, at  FIGS. 13A to 18A , chromatic curvature-of-field at the wide-angle end (W); at  FIGS. 13B to 18B , chromatic curvature-of-field at the mid-focal-length position (M); and at  FIGS. 13C to 18C , chromatic curvature-of-field at the telephoto end (T). The plots in  FIGS. 13A-13C  to  18 A- 18 C are similar to those at  FIGS. 7B to 12B ,  7 E to  12 E, and  7 H to  12 H, indicating the curvature of field for the C-line (with a wavelength of 656.28 nm), the d-line (with a wavelength of 587.56 nm), and the g-line (with a wavelength of 435.84 nm) with respect to each of the sagittal image surface S and the tangential image surface T. 
         [0120]      FIGS. 19A-19J  to  21 A- 21 J,  FIGS. 22A-22J  to  24 A- 24 J,  FIGS. 25A-25J  to  27 A- 27 J,  FIGS. 28A-28J  to  30 A- 30 I,  FIGS. 31A-31J  to  33 A- 33 J, and  FIGS. 34A-34J  to  36 A- 36 J are lateral aberration diagrams corresponding to Examples 1 to 6 (EX1 to EX6) respectively, showing chromatic coma (mm) at the wide-angle end (W), the mid-focal-length position (M), and the telephoto end (T).  FIGS. 19A-19E  to  36 A- 36 E are the lateral aberrations in a tangential beam, and  FIGS. 19F-19J  to  36 F- 36 J are the lateral aberrations in a sagittal beam. There are shown the lateral aberrations at different relative field heights (half-angle of view ω°), indicated at “RELATIVE FIELD HEIGHT,” by a solid line for d-line (with a wavelength of 587.56 nm); by a dash-and-dot line for the C-line (with a wavelength of 656.28 nm); and by a broken line for the g-line (with a wavelength of 435.84 nm). A relative field height is a relative image height as normalized with respect to the maximum image height Y′. 
       Example 1 
       [0121]      
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
             
               
               
               
               
               
               
               
               
             
               
             
               
               
               
               
               
             
               
             
               
               
               
             
           
               
                   
               
               
                 Unit: mm 
               
               
                   
               
             
             
               
                 Surface Data 
               
             
          
           
               
                   
                 Surface No. 
                 r 
                 d 
                 nd 
                 vd 
               
               
                   
                   
               
               
                   
                 Object Surface 
                 ∞ 
                 d0 
               
               
                   
                  1 
                 55.466 
                 2.30 
                 1.72916 
                 54.67 
               
               
                   
                  2 
                 22.882 
                 5.75 
               
               
                   
                  *3 
                 42.477 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  4 
                 31.616 
                 1.80 
                 1.72916 
                 54.67 
               
               
                   
                  5 
                 19.407 
                 7.62 
               
               
                   
                  6 
                 201.373 
                 1.73 
                 1.80420 
                 46.50 
               
               
                   
                  7 
                 27.873 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  *8 
                 23.059 
                 6.63 
               
               
                   
                  9 
                 39.970 
                 5.45 
                 1.68893 
                 31.16 
               
               
                   
                  10 
                 −175.401 
                 26.97 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  11 
                 49.393 
                 2.00 
                 1.80518 
                 25.46 
               
               
                   
                  12 
                 25.904 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  13 
                 25.904 
                 4.84 
                 1.64769 
                 33.84 
               
               
                   
                  14 
                 −302.784 
                 6.15 
               
               
                   
                  15 (Aperture) 
                 ∞ 
                 1.90 
               
               
                   
                  16 
                 18.791 
                 8.37 
                 1.49700 
                 81.61 
               
               
                   
                  17 
                 −46.108 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  18 
                 −46.108 
                 1.00 
                 1.72916 
                 54.67 
               
               
                   
                  19 
                 1198.193 
                 1.00 
               
               
                   
                  20 
                 38.088 
                 1.00 
                 1.80420 
                 46.50 
               
               
                   
                  21 
                 11.617 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  22 
                 11.617 
                 7.85 
                 1.49700 
                 81.61 
               
               
                   
                  23 
                 −13.915 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  24 
                 −13.915 
                 1.00 
                 1.72916 
                 54.67 
               
               
                   
                  25 
                 63.311 
                 1.21 
               
               
                   
                 *26 
                 999.995 
                 4.41 
                 1.58313 
                 59.39 
               
               
                   
                 *27 
                 −21.943 
                 37.70 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  28 
                 ∞ 
                 1.90 
                 1.51680 
                 64.20 
               
               
                   
                  29 
                 ∞ 
                 1.00 
               
               
                   
                 Image Surface 
                 ∞ 
                 0.00 
               
               
                   
                   
               
             
          
           
               
                 Aspherical Surface Data 
               
             
          
           
               
                 Surface 
                 K 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
                 A14 
               
               
                   
               
               
                 3 
                 1.487 
                 1.168E−05 
                 −4.148E09 
                 1.101E−12 
                 1.894E−14 
                 −2.952E−17 
                 −9.759E−21 
               
               
                 8 
                 −4.715 
                 3.700E−05 
                 −1.310E−07 
                 2.082E−10 
                 −3.243E−13 
                 1.792E−17 
                 −9.759E−21 
               
               
                 26 
                 0.000 
                 2.136E−05 
                 1.939E−07 
                 1.663E−09 
                 1.020E−11 
               
               
                 27 
                 −10.003 
                 −9.654E−05 
                 1.095E−06 
                 −7.277E−09 
                 5.471E−11 
               
               
                   
               
             
          
           
               
                 Miscellaneous Data 
               
               
                 Zoom Ratio 1.84 
               
             
          
           
               
                   
                   
                 Wide (W) 
                 Mid (M) 
                 Tele (T) 
               
               
                   
                   
               
               
                   
                 f 
                 18.50 
                 25.08 
                 34.00 
               
               
                   
                 2ω 
                 60.54 
                 46.60 
                 35.24 
               
               
                   
                 BF 
                 1.00 
                 1.00 
                 1.00 
               
               
                   
                 TL 
                 139.69 
                 134.64 
                 136.74 
               
               
                   
                 Fno 
                 3.6 
                 4.15 
                 4.63 
               
               
                   
                 Y′ 
                 21.63 
                 21.63 
                 21.63 
               
               
                   
                 d0 
                 ∞ 
                 ∞ 
                 ∞ 
               
               
                   
                 d10 
                 26.973 
                 12.514 
                 1.850 
               
               
                   
                 d27 
                 37.70 
                 47.12 
                 59.88 
               
               
                   
                   
               
             
          
           
               
                 Focal Lengths of Lens Groups etc. 
               
               
                   
               
             
          
           
               
                   
                 1st Lens Group Gr1 
                 −26.69 
               
               
                   
                 2nd Lens Group Gr2 
                 38.19 
               
               
                   
                 Front Group GrF 
                 80.86 
               
               
                   
                 Rear Group GrR 
                 57.98 
               
               
                   
                 3-Element Cemented Lens LS 
                 −29.60 
               
               
                   
                 1st Lens Element L1 
                 −21.14 
               
               
                   
                 2nd Lens Element L2 
                 14.19 
               
               
                   
                 3rd Lens Element L3 
                 −15.56 
               
               
                   
                   
               
             
          
         
       
     
       Example 2 
       [0122]      
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
             
               
               
               
               
               
               
               
               
             
               
             
               
               
               
               
               
             
               
             
               
               
               
             
           
               
                   
               
               
                 Unit: mm 
               
               
                   
               
             
             
               
                 Surface Data 
               
             
          
           
               
                   
                 Surface No. 
                 r 
                 d 
                 nd 
                 vd 
               
               
                   
                   
               
               
                   
                 Object Surface 
                 ∞ 
                 d0 
               
               
                   
                  1 
                 56.894 
                 2.30 
                 1.72916 
                 54.67 
               
               
                   
                  2 
                 23.175 
                 5.62 
               
               
                   
                  *3 
                 44.129 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  4 
                 31.909 
                 1.80 
                 1.72916 
                 54.67 
               
               
                   
                  5 
                 19.270 
                 7.64 
               
               
                   
                  6 
                 189.960 
                 1.70 
                 1.80420 
                 46.50 
               
               
                   
                  7 
                 28.692 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  *8 
                 23.892 
                 6.86 
               
               
                   
                  9 
                 40.196 
                 5.43 
                 1.68893 
                 31.16 
               
               
                   
                  10 
                 −202.837 
                 26.95 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  11 
                 36.049 
                 2.00 
                 1.80518 
                 25.46 
               
               
                   
                  12 
                 21.790 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  13 
                 21.790 
                 5.06 
                 1.64769 
                 33.84 
               
               
                   
                  14 
                 148.319 
                 6.42 
               
               
                   
                  15 (Aperture) 
                 ∞ 
                 1.90 
               
               
                   
                  16 
                 21.200 
                 7.43 
                 1.49700 
                 81.61 
               
               
                   
                  17 
                 −27.461 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  18 
                 −27.461 
                 1.12 
                 1.72916 
                 54.67 
               
               
                   
                  19 
                 −246.857 
                 2.33 
               
               
                   
                  20 
                 27.538 
                 1.00 
                 1.80420 
                 46.50 
               
               
                   
                  21 
                 11.317 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  22 
                 11.317 
                 7.15 
                 1.49700 
                 81.61 
               
               
                   
                  23 
                 −23.878 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  24 
                 −23.878 
                 1.00 
                 1.72916 
                 54.67 
               
               
                   
                  25 
                 51.442 
                 1.34 
               
               
                   
                 *26 
                 1000.213 
                 3.95 
                 1.58313 
                 59.39 
               
               
                   
                 *27 
                 −28.052 
                 37.70 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  28 
                 ∞ 
                 1.90 
                 1.51680 
                 64.20 
               
               
                   
                  29 
                 ∞ 
                 1.00 
               
               
                   
                 Image Surface 
                 ∞ 
                 0.00 
               
               
                   
                   
               
             
          
           
               
                 Aspherical Surface Data 
               
             
          
           
               
                 Surface 
                 K 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
                 A14 
               
               
                   
               
               
                 3 
                 0.732 
                 1.552E−05 
                 −7.975E−09 
                 1.063E−11 
                 7.872E−15 
                 −2.952E−17 
                 −9.759E−21 
               
               
                 8 
                 −3.902 
                 2.960E−05 
                 −1.061E−07 
                 1.524E−10 
                 −2.983E−13 
                 1.792E−17 
                 −9.759E−21 
               
               
                 26 
                 0.000 
                 2.037E−05 
                 3.707E−07 
                 −1.487E−09 
                 2.256E−11 
               
               
                 27 
                 −14.275 
                 −5.950E−05 
                 8.978E−07 
                 −5.962E−09 
                 3.899E−11 
               
               
                   
               
             
          
           
               
                 Miscellaneous Data 
               
               
                 Zoom Ratio 1.84 
               
             
          
           
               
                   
                   
                 Wide (W) 
                 Mid (M) 
                 Tele (T) 
               
               
                   
                   
               
               
                   
                 f 
                 18.50 
                 25.08 
                 34.00 
               
               
                   
                 2ω 
                 60.55 
                 46.59 
                 35.24 
               
               
                   
                 BF 
                 1.00 
                 1.00 
                 1.00 
               
               
                   
                 TL 
                 139.69 
                 134.66 
                 136.76 
               
               
                   
                 Fno 
                 3.6 
                 4.15 
                 4.67 
               
               
                   
                 Y′ 
                 21.63 
                 21.63 
                 21.63 
               
               
                   
                 d0 
                 ∞ 
                 ∞ 
                 ∞ 
               
               
                   
                 d10 
                 26.949 
                 12.504 
                 1.850 
               
               
                   
                 d27 
                 37.70 
                 47.12 
                 59.88 
               
               
                   
                   
               
             
          
           
               
                 Focal Lengths of Lens Groups etc. 
               
               
                   
               
             
          
           
               
                   
                 1st Lens Group Gr1 
                 −26.68 
               
               
                   
                 2nd Lens Group Gr2 
                 38.17 
               
               
                   
                 Front Group GrF 
                 89.02 
               
               
                   
                 Rear Group GrR 
                 53.45 
               
               
                   
                 3-Element Cemented Lens LS 
                 −48.11 
               
               
                   
                 1st Lens Element L1 
                 −24.56 
               
               
                   
                 2nd Lens Element L2 
                 16.57 
               
               
                   
                 3rd Lens Element L3 
                 −22.24 
               
               
                   
                   
               
             
          
         
       
     
       Example 3 
       [0123]      
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
             
               
               
               
               
               
               
               
               
             
               
             
               
               
               
               
               
             
               
             
               
               
               
             
           
               
                   
               
               
                 Unit: mm 
               
               
                   
               
             
             
               
                 Surface Data 
               
             
          
           
               
                   
                 Surface No. 
                 r 
                 d 
                 nd 
                 vd 
               
               
                   
                   
               
               
                   
                 Object Surface 
                 ∞ 
                 d0 
               
               
                   
                  1 
                 56.700 
                 2.29 
                 1.72916 
                 54.67 
               
               
                   
                  2 
                 22.554 
                 5.87 
               
               
                   
                  *3 
                 41.654 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  4 
                 31.079 
                 1.80 
                 1.72916 
                 54.67 
               
               
                   
                  5 
                 20.060 
                 7.48 
               
               
                   
                  6 
                 185.198 
                 2.80 
                 1.80420 
                 46.50 
               
               
                   
                  7 
                 27.947 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  *8 
                 23.102 
                 7.04 
               
               
                   
                  9 
                 40.530 
                 5.29 
                 1.68893 
                 31.16 
               
               
                   
                  10 
                 −214.872 
                 26.65 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  11 
                 36.851 
                 1.03 
                 1.80518 
                 25.46 
               
               
                   
                  12 
                 24.227 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  13 
                 24.227 
                 4.83 
                 1.64769 
                 33.84 
               
               
                   
                  14 
                 252.802 
                 6.02 
               
               
                   
                  15 (Aperture) 
                 ∞ 
                 1.90 
               
               
                   
                  16 
                 21.433 
                 7.21 
                 1.49700 
                 81.61 
               
               
                   
                  17 
                 −28.120 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  18 
                 −28.120 
                 1.40 
                 1.72916 
                 54.67 
               
               
                   
                  19 
                 −363.927 
                 1.00 
               
               
                   
                  20 
                 30.960 
                 1.55 
                 1.83481 
                 42.71 
               
               
                   
                  21 
                 12.048 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  22 
                 12.048 
                 7.17 
                 1.49700 
                 81.61 
               
               
                   
                  23 
                 −19.165 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  24 
                 −19.165 
                 2.00 
                 1.67293 
                 55.04 
               
               
                   
                  25 
                 46.395 
                 1.41 
               
               
                   
                 *26 
                 1001.959 
                 4.06 
                 1.58313 
                 59.39 
               
               
                   
                 *27 
                 −26.005 
                 37.70 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  28 
                 ∞ 
                 1.90 
                 1.51680 
                 64.20 
               
               
                   
                  29 
                 ∞ 
                 1.00 
               
               
                   
                 Image Surface 
                 ∞ 
                 0.00 
               
               
                   
                   
               
             
          
           
               
                 Aspherical Surface Data 
               
             
          
           
               
                 Surface 
                 K 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
                 A14 
               
               
                   
               
               
                 3 
                 2.575 
                 9.770E−06 
                 −7.840E−09 
                 9.280E−12 
                 −4.014E−14 
                 −2.952E−17 
                 −9.759E−21 
               
               
                 8 
                 −5.577 
                 4.396E−05 
                 −1.562E−07 
                 2.102E−10 
                 −2.057E−13 
                 1.792E−17 
                 −9.759E−21 
               
               
                 26 
                 0.000 
                 1.808E−05 
                 3.577E−07 
                 −8.150E−10 
                 2.178E−11 
               
               
                 27 
                 −13.787 
                 −7.676E−05 
                 1.055E−06 
                 −7.110E−09 
                 5.003E−11 
               
               
                   
               
             
          
           
               
                 Miscellaneous Data 
               
               
                 Zoom Ratio 1.84 
               
             
          
           
               
                   
                   
                 Wide (W) 
                 Mid (M) 
                 Tele (T) 
               
               
                   
                   
               
               
                   
                 f 
                 18.50 
                 25.08 
                 34.00 
               
               
                   
                 2ω 
                 60.55 
                 46.59 
                 35.24 
               
               
                   
                 BF 
                 1.00 
                 1.00 
                 1.00 
               
               
                   
                 TL 
                 139.49 
                 134.63 
                 136.87 
               
               
                   
                 Fno 
                 3.6 
                 4.15 
                 4.68 
               
               
                   
                 Y′ 
                 21.63 
                 21.63 
                 21.63 
               
               
                   
                 d0 
                 ∞ 
                 ∞ 
                 ∞ 
               
               
                   
                 d10 
                 26.653 
                 12.379 
                 1.851 
               
               
                   
                 d27 
                 37.70 
                 47.11 
                 59.88 
               
               
                   
                   
               
             
          
           
               
                 Focal Lengths of Lens Groups etc. 
               
               
                   
               
             
          
           
               
                   
                 1st Lens Group Gr1 
                 −26.52 
               
               
                   
                 2nd Lens Group Gr2 
                 37.94 
               
               
                   
                 Front Group GrF 
                 76.83 
               
               
                   
                 Rear Group GrR 
                 58.87 
               
               
                   
                 3-Element Cemented Lens LS 
                 −42.03 
               
               
                   
                 1st Lens Element L1 
                 −24.54 
               
               
                   
                 2nd Lens Element L2 
                 16.11 
               
               
                   
                 3rd Lens Element L3 
                 −19.91 
               
               
                   
                   
               
             
          
         
       
     
       Example 4 
       [0124]      
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
             
               
               
               
               
               
               
               
               
             
               
             
               
               
               
               
               
             
               
             
               
               
               
             
           
               
                   
               
               
                 Unit: mm 
               
               
                   
               
             
             
               
                 Surface Data 
               
             
          
           
               
                   
                 Surface No. 
                 r 
                 d 
                 nd 
                 vd 
               
               
                   
                   
               
               
                   
                 Object Surface 
                 ∞ 
                 d0 
               
               
                   
                  1 
                 54.832 
                 2.30 
                 1.72916 
                 54.67 
               
               
                   
                  2 
                 22.758 
                 5.71 
               
               
                   
                  *3 
                 41.464 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  4 
                 31.000 
                 1.90 
                 1.72916 
                 54.67 
               
               
                   
                  5 
                 19.022 
                 7.80 
               
               
                   
                  6 
                 217.416 
                 1.89 
                 1.80420 
                 46.50 
               
               
                   
                  7 
                 29.740 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  *8 
                 24.392 
                 7.15 
               
               
                   
                  9 
                 42.198 
                 5.19 
                 1.68893 
                 31.16 
               
               
                   
                  10 
                 −191.291 
                 26.89 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  11 
                 43.386 
                 2.00 
                 1.80518 
                 25.46 
               
               
                   
                  12 
                 25.144 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  13 
                 25.144 
                 3.83 
                 1.64769 
                 33.84 
               
               
                   
                  14 
                 −1413.103 
                 6.06 
               
               
                   
                  15 (Aperture) 
                 ∞ 
                 1.90 
               
               
                   
                  16 
                 20.205 
                 6.61 
                 1.49700 
                 81.61 
               
               
                   
                  17 
                 −31.130 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  18 
                 −31.130 
                 2.50 
                 1.72916 
                 54.67 
               
               
                   
                  19 
                 −147.824 
                 1.00 
               
               
                   
                  20 
                 41.294 
                 1.37 
                 1.77250 
                 49.62 
               
               
                   
                  21 
                 11.607 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  22 
                 11.607 
                 7.37 
                 1.49700 
                 81.61 
               
               
                   
                  23 
                 −18.185 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  24 
                 −18.185 
                 2.00 
                 1.77250 
                 49.62 
               
               
                   
                  25 
                 60.429 
                 1.24 
               
               
                   
                 *26 
                 999.957 
                 4.24 
                 1.58313 
                 59.39 
               
               
                   
                 *27 
                 −23.539 
                 37.70 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  28 
                 ∞ 
                 1.90 
                 1.51680 
                 64.20 
               
               
                   
                  29 
                 ∞ 
                 1.00 
               
               
                   
                 Image Surface 
                 ∞ 
                 0.00 
               
               
                   
                   
               
             
          
           
               
                 Aspherical Surface Data 
               
             
          
           
               
                 Surface 
                 K 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
                 A14 
               
               
                   
               
               
                 3 
                 2.501 
                 9.645E−06 
                 −4.182E−09 
                 −8.855E−12 
                 −1.018E−14 
                 −2.952E−17 
                 −9.759E−21 
               
               
                 8 
                 −5.646 
                 3.812E−05 
                 −1.391E−07 
                 1.895E−10 
                 −2.501E−13 
                 1.792E−17 
                 −9.759E−21 
               
               
                 26 
                 0.000 
                 2.251E−05 
                 1.967E−07 
                 1.352E−09 
                 1.091E−11 
               
               
                 27 
                 −12.375 
                 −9.225E−05 
                 1.138E−06 
                 −7.236E−09 
                 5.015E−11 
               
               
                   
               
             
          
           
               
                 Miscellaneous Data 
               
               
                 Zoom Ratio 1.84 
               
             
          
           
               
                   
                   
                 Wide (W) 
                 Mid (M) 
                 Tele (T) 
               
               
                   
                   
               
               
                   
                 f 
                 18.50 
                 25.08 
                 34.00 
               
               
                   
                 2ω 
                 60.55 
                 46.59 
                 35.24 
               
               
                   
                 BF 
                 1.00 
                 1.00 
                 1.00 
               
               
                   
                 TL 
                 139.65 
                 134.65 
                 136.78 
               
               
                   
                 Fno 
                 3.6 
                 4.15 
                 4.66 
               
               
                   
                 Y′ 
                 21.63 
                 21.63 
                 21.63 
               
               
                   
                 d0 
                 ∞ 
                 ∞ 
                 ∞ 
               
               
                   
                 d10 
                 26.891 
                 12.479 
                 1.850 
               
               
                   
                 d27 
                 37.70 
                 47.12 
                 59.88 
               
               
                   
                   
               
             
          
           
               
                 Focal Lengths of Lens Groups etc. 
               
               
                   
               
             
          
           
               
                   
                 1st Lens Group Gr1 
                 −26.65 
               
               
                   
                 2nd Lens Group Gr2 
                 38.13 
               
               
                   
                 Front Group GrF 
                 77.77 
               
               
                   
                 Rear Group GrR 
                 59.48 
               
               
                   
                 3-Element Cemented Lens LS 
                 −30.17 
               
               
                   
                 1st Lens Element L1 
                 −21.33 
               
               
                   
                 2nd Lens Element L2 
                 15.53 
               
               
                   
                 3rd Lens Element L3 
                 −17.90 
               
               
                   
                   
               
             
          
         
       
     
       Example 5 
       [0125]      
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
             
               
               
               
               
               
               
               
               
             
               
             
               
               
               
               
               
             
               
             
               
               
               
             
           
               
                   
               
               
                 Unit: mm 
               
               
                   
               
             
             
               
                 Surface Data 
               
             
          
           
               
                   
                 Surface No. 
                 r 
                 d 
                 nd 
                 vd 
               
               
                   
                   
               
               
                   
                 Object Surface 
                 ∞ 
                 d0 
               
               
                   
                  1 
                 57.160 
                 2.30 
                 1.72916 
                 54.67 
               
               
                   
                  2 
                 22.528 
                 6.58 
               
               
                   
                  *3 
                 49.006 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  4 
                 34.972 
                 1.80 
                 1.72916 
                 54.67 
               
               
                   
                  5 
                 20.582 
                 6.82 
               
               
                   
                  6 
                 140.113 
                 2.83 
                 1.80420 
                 46.50 
               
               
                   
                  7 
                 26.861 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  *8 
                 22.282 
                 6.38 
               
               
                   
                  9 
                 38.568 
                 5.53 
                 1.68893 
                 31.16 
               
               
                   
                  10 
                 −174.256 
                 27.19 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  11 
                 45.249 
                 2.00 
                 1.83512 
                 41.83 
               
               
                   
                  12 
                 23.574 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  13 
                 23.574 
                 3.39 
                 1.62745 
                 50.43 
               
               
                   
                  14 
                 −229.978 
                 6.13 
               
               
                   
                  15 (Aperture) 
                 ∞ 
                 1.90 
               
               
                   
                  16 
                 20.400 
                 6.36 
                 1.55344 
                 50.79 
               
               
                   
                  17 
                 −26.810 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  18 
                 −26.810 
                 2.50 
                 1.83481 
                 42.72 
               
               
                   
                  19 
                 −85.945 
                 1.00 
               
               
                   
                  20 
                 55.650 
                 2.00 
                 1.83492 
                 42.42 
               
               
                   
                  21 
                 12.055 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  22 
                 12.055 
                 6.97 
                 1.50026 
                 80.83 
               
               
                   
                  23 
                 −20.892 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  24 
                 −20.892 
                 2.00 
                 1.75500 
                 47.38 
               
               
                   
                  25 
                 62.339 
                 1.23 
               
               
                   
                 *26 
                 1000.024 
                 4.18 
                 1.58313 
                 59.39 
               
               
                   
                 *27 
                 −23.764 
                 37.73 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  28 
                 ∞ 
                 1.90 
                 1.51680 
                 64.20 
               
               
                   
                  29 
                 ∞ 
                 1.00 
               
               
                   
                 Image Surface 
                 ∞ 
                 0.00 
               
               
                   
                   
               
             
          
           
               
                 Aspherical Surface Data 
               
             
          
           
               
                 Surface 
                 K 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
                 A14 
               
               
                   
               
               
                 3 
                 −1.652 
                 1.460E−05 
                 1.409E−08 
                 −7.462E−11 
                 1.315E−13 
                 −2.952E−17 
                 −9.759E−21 
               
               
                 8 
                 −4.451 
                 3.729E−05 
                 −1.113E−07 
                 3.954E−11 
                 1.091E−13 
                 1.792E−17 
                 −9.759E−21 
               
               
                 26 
                 0.000 
                 2.144E−05 
                 2.084E−07 
                 1.101E−09 
                 1.498E−11 
               
               
                 27 
                 −12.499 
                 −9.038E−05 
                 1.124E−06 
                 −7.338E−09 
                 5.385E−11 
               
               
                   
               
             
          
           
               
                 Miscellaneous Data 
               
               
                 Zoom Ratio 1.85 
               
             
          
           
               
                   
                   
                 Wide (W) 
                 Mid (M) 
                 Tele (T) 
               
               
                   
                   
               
               
                   
                 f 
                 18.36 
                 25.00 
                 34.01 
               
               
                   
                 2ω 
                 60.92 
                 46.72 
                 35.24 
               
               
                   
                 BF 
                 1.00 
                 1.00 
                 1.00 
               
               
                   
                 TL 
                 139.78 
                 134.59 
                 136.65 
               
               
                   
                 Fno 
                 3.6 
                 4.15 
                 4.67 
               
               
                   
                 Y′ 
                 21.63 
                 21.63 
                 21.63 
               
               
                   
                 d0 
                 ∞ 
                 ∞ 
                 ∞ 
               
               
                   
                 d10 
                 27.192 
                 12.560 
                 1.850 
               
               
                   
                 d27 
                 37.73 
                 47.15 
                 59.91 
               
               
                   
                   
               
             
          
           
               
                 Focal Lengths of Lens Groups etc. 
               
               
                   
               
             
          
           
               
                   
                 1st Lens Group Gr1 
                 −26.71 
               
               
                   
                 2nd Lens Group Gr2 
                 37.88 
               
               
                   
                 Front Group GrF 
                 80.38 
               
               
                   
                 Rear Group GrR 
                 58.19 
               
               
                   
                 3-Element Cemented Lens LS 
                 −26.35 
               
               
                   
                 1st Lens Element L1 
                 −18.82 
               
               
                   
                 2nd Lens Element L2 
                 16.44 
               
               
                   
                 3rd Lens Element L3 
                 −20.51 
               
               
                   
                   
               
             
          
         
       
     
       Example 6 
       [0126]      
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
             
               
               
               
               
               
               
               
               
             
               
             
               
               
               
               
               
             
               
             
               
               
               
             
           
               
                   
               
               
                 Unit: mm 
               
               
                   
               
             
             
               
                 Surface Data 
               
             
          
           
               
                   
                 Surface No. 
                 r 
                 d 
                 nd 
                 vd 
               
               
                   
                   
               
               
                   
                 Object Surface 
                 ∞ 
                 d0 
               
               
                   
                  1 
                 56.585 
                 2.30 
                 1.68447 
                 53.68 
               
               
                   
                  2 
                 22.605 
                 5.75 
               
               
                   
                  *3 
                 41.517 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  4 
                 31.000 
                 1.80 
                 1.61797 
                 63.40 
               
               
                   
                  5 
                 18.696 
                 8.04 
               
               
                   
                  6 
                 427.972 
                 1.70 
                 1.80420 
                 46.50 
               
               
                   
                  7 
                 28.437 
                 0.08 
                 1.51400 
                 53.00 
               
               
                   
                  *8 
                 23.478 
                 7.12 
               
               
                   
                  9 
                 42.076 
                 5.19 
                 1.68893 
                 31.16 
               
               
                   
                  10 
                 −156.518 
                 26.86 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  11 
                 40.556 
                 2.00 
                 1.83481 
                 42.72 
               
               
                   
                  12 
                 21.529 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  13 
                 21.529 
                 3.68 
                 1.59770 
                 51.25 
               
               
                   
                  14 
                 −199.895 
                 6.07 
               
               
                   
                  15 (Aperture) 
                 ∞ 
                 1.90 
               
               
                   
                  16 
                 20.614 
                 6.63 
                 1.55421 
                 50.56 
               
               
                   
                  17 
                 −26.708 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  18 
                 −26.708 
                 2.50 
                 1.83481 
                 42.72 
               
               
                   
                  19 
                 −82.290 
                 1.00 
               
               
                   
                  20 
                 51.558 
                 1.94 
                 1.83481 
                 42.72 
               
               
                   
                  21 
                 11.479 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  22 
                 11.479 
                 6.78 
                 1.49700 
                 81.60 
               
               
                   
                  23 
                 −26.044 
                 0.01 
                 1.51400 
                 42.80 
               
               
                   
                  24 
                 −26.044 
                 2.00 
                 1.78347 
                 45.49 
               
               
                   
                  25 
                 60.275 
                 1.45 
               
               
                   
                 *26 
                 1000.070 
                 4.25 
                 1.58313 
                 59.39 
               
               
                   
                 *27 
                 −24.363 
                 37.70 
               
               
                   
                   
                   
                 (Variable) 
               
               
                   
                  28 
                 ∞ 
                 1.90 
                 1.51680 
                 64.20 
               
               
                   
                  29 
                 ∞ 
                 1.00 
               
               
                   
                 Image Surface 
                 ∞ 
                 0.00 
               
               
                   
                   
               
             
          
           
               
                 Aspherical Surface Data 
               
             
          
           
               
                 Surface 
                 K 
                 A4 
                 A6 
                 A8 
                 A10 
                 A12 
                 A14 
               
               
                   
               
               
                 3 
                 −0.626 
                 1.579E−05 
                 −2.108E−09 
                 −1.058E−12 
                 3.548E−14 
                 −2.952E−17 
                 −9.759E−21 
               
               
                 8 
                 −4.250 
                 3.205E−05 
                 −1.220E−07 
                 2.152E−10 
                 −3.609E−13 
                 1.792E−17 
                 −9.759E−21 
               
               
                 26 
                 0.000 
                 2.400E−05 
                 1.127E−07 
                 2.441E−09 
                 7.976E−12 
               
               
                 27 
                 −13.833 
                 −9.435E−05 
                 1.151E−06 
                 −7.973E−09 
                 5.512E−11 
               
               
                   
               
             
          
           
               
                 Miscellaneous Data 
               
               
                 Zoom Ratio 1.84 
               
             
          
           
               
                   
                   
                 Wide (W) 
                 Mid (M) 
                 Tele (T) 
               
               
                   
                   
               
               
                   
                 f 
                 18.50 
                 25.08 
                 33.99 
               
               
                   
                 2ω 
                 60.56 
                 46.60 
                 35.25 
               
               
                   
                 BF 
                 1.00 
                 1.00 
                 1.00 
               
               
                   
                 TL 
                 139.66 
                 134.67 
                 136.80 
               
               
                   
                 Fno 
                 3.6 
                 4.15 
                 4.68 
               
               
                   
                 Y′ 
                 21.63 
                 21.63 
                 21.63 
               
               
                   
                 d0 
                 ∞ 
                 ∞ 
                 ∞ 
               
               
                   
                 d10 
                 26.863 
                 12.467 
                 1.850 
               
               
                   
                 d27 
                 37.70 
                 47.11 
                 59.86 
               
               
                   
                   
               
             
          
           
               
                 Focal Lengths of Lens Groups etc. 
               
               
                   
               
             
          
           
               
                   
                 1st Lens Group Gr1 
                 −26.64 
               
               
                   
                 2nd Lens Group Gr2 
                 38.10 
               
               
                   
                 Front Group GrF 
                 78.91 
               
               
                   
                 Rear Group GrR 
                 59.51 
               
               
                   
                 3-Element Cemented Lens LS 
                 −26.27 
               
               
                   
                 1st Lens Element L1 
                 −18.09 
               
               
                   
                 2nd Lens Element L2 
                 17.05 
               
               
                   
                 3rd Lens Element L3 
                 −22.98 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
             
             
               
                   
                   
                 (1) 
                 (2) 
                 (3) 
               
               
                   
                   
                 (rs2 + rs1)/(rs2 − rs1) 
                 v2 − v1 
                 v2 − v3 
               
               
                   
                   
               
               
                   
                 EX1 
                 0.09 
                 35.11 
                 26.93 
               
               
                   
                 EX2 
                 0.36 
                 35.11 
                 26.93 
               
               
                   
                 EX3 
                 0.23 
                 38.90 
                 26.57 
               
               
                   
                 EX4 
                 0.22 
                 31.99 
                 31.99 
               
               
                   
                 EX5 
                 0.27 
                 38.41 
                 33.45 
               
               
                   
                 EX6 
                 0.39 
                 38.88 
                 36.11 
               
               
                   
                   
               
             
          
           
               
                   
                   
                 (4) 
                 (5) 
                 (6): ΔX_max/ΔX_min 
               
             
          
           
               
                   
                   
                 f1/f2 
                 fs/f2_r 
                 1st Surface 
                 2nd Surface 
               
               
                   
                   
               
               
                   
                 EX1 
                 −0.70 
                 −0.51 
                 5.5053 
                 4.9241 
               
               
                   
                 EX2 
                 −0.70 
                 −0.90 
                 5.5145 
                 4.9443 
               
               
                   
                 EX3 
                 −0.70 
                 −0.71 
                 5.5392 
                 4.9207 
               
               
                   
                 EX4 
                 −0.70 
                 −0.51 
                 5.5074 
                 4.9264 
               
               
                   
                 EX5 
                 −0.71 
                 −0.45 
                 5.5076 
                 4.9126 
               
               
                   
                 EX6 
                 −0.70 
                 −0.44 
                 5.5052 
                 4.9217 
               
               
                   
                   
               
             
          
         
       
     
         [0127]    DU digital appliance 
         [0128]    LU imaging optical device 
         [0129]    ZL zoom lens system 
         [0130]    Gr 1  first lens group 
         [0131]    Gr 2  second lens group 
         [0132]    GrF front group 
         [0133]    GrR rear group 
         [0134]    LS three-element cemented lens 
         [0135]    L 1  first lens element 
         [0136]    L 2  second lens element 
         [0137]    L 3  third lens element 
         [0138]    ST aperture stop 
         [0139]    SR image sensor 
         [0140]    SS light-receiving surface 
         [0141]    IM image surface 
         [0142]    AX optical axis 
         [0143]      1  signal processing portion 
         [0144]      2  control portion 
         [0145]      3  memory 
         [0146]      4  operation portion 
         [0147]      5  display portion