COMPOSITE OPTICAL ELEMENT AND OPTICAL SYSTEM INCLUDING THE SAME

Abstract

A composite optical element includes a glass lens and a resin lens that are joined together. The resin lens has an aspheric shape. When Nd is a refractive index of the resin lens, ?d is an Abbe number of the resin lens, and ?gF is a partial dispersion ratio of the resin lens, Nd, ?d, and ?gF are appropriately set.

Claims

1. A composite optical element comprising: a glass lens and a resin lens that are joined together, wherein the resin lens has an aspheric shape, and wherein, when Nd is a refractive index of the resin lens, ?d is an Abbe number of the resin lens, and ?gF is a partial dispersion ratio of the resin lens, the following inequalities are satisfied:
1.900<Nd+(0.014??d)<2.045
30.0<?d<35.0
0.6200<?gF+(0.0024??d)<0.6900

2. The composite optical element according to claim 1, wherein, when Tmax and Tmin are respectively a maximum thickness and a minimum thickness of the resin lens in a direction of an optical axis within an effective diameter, the following inequality is satisfied:
1.0<Tmax/Tmin<10.0

3. The composite optical element according to claim 1, wherein, when Tg is a thickness of the glass lens along an optical axis and Tp is a thickness of the resin lens along the optical axis, the following inequality is satisfied:
3<Tg/Tp<200

4. The composite optical element according to claim 1, wherein, when fg is a focal length of the glass lens and fp is a focal length of the resin lens, the following inequality is satisfied:
|fg/fp|<0.30

5. The composite optical element according to claim 1, wherein the resin lens is formed from a photocurable resin.

6. The composite optical element according to claim 1, wherein, when R is a curing shrinkage ratio of the resin lens, the following inequality is satisfied:
?<7.5[%]

7. The composite optical element according to claim 1, wherein, when a is a coefficient of linear expansion of the resin lens, the following inequality is satisfied:
60?10.sup.?6<?<100?10.sup.?6[1/? C.]

8. The composite optical element according to claim 1, wherein, when Ndg is a refractive index of the glass lens, the following inequality is satisfied:
0.98<Ndg/Nd<1.40

9. The composite optical element according to claim 1, wherein, when ?dg is an Abbe number of the glass lens, the following inequality is satisfied:
35.0<?dg<100.0

10. The composite optical element according to claim 1, wherein, when aw is a hygroscopic expansion ratio of the resin lens, the following inequality is satisfied:
?w<0.50[%]

11. An optical system comprising: a composite optical element including a glass lens and a resin lens that are joined together, wherein the resin lens has an aspheric shape, and wherein, when Nd is a refractive index of the resin lens, ?d is an Abbe number of the resin lens, and ?gF is a partial dispersion ratio of the resin lens, the following inequalities are satisfied:
1.900<Nd+(0.014??d)<2.045
30.0<?d<35.0
0.6200<?gF+(0.0024??d)<0.6900

12. The optical system according to claim 11, wherein the composite optical element is disposed on an image side of a lens disposed closest to an object side among lenses disposed in the optical system.

13. The optical system according to claim 11, wherein the optical system includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a rear group that are arranged in that order from an object side to an image side, the rear group including at least one lens unit, wherein intervals between the lens units that are adjacent to each other vary during zooming, and wherein the composite optical element is disposed on the image side of the first lens unit.

14. The optical system according to claim 13, wherein the composite optical element is disposed closest to the object side in the second lens unit.

15. The optical system according to claim 13, wherein the rear group includes a fourth lens unit disposed closest to the object side, and wherein the composite optical element is included in the fourth lens unit.

16. The optical system according to claim 11, wherein the optical system includes a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a rear group that are arranged in that order from an object side to an image side, the rear group including at least one lens unit, wherein intervals between the lens units that are adjacent to each other vary during zooming, and wherein the composite optical element is included in the first lens unit.

17. The optical system according to claim 11, wherein the optical system includes a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a rear group that are arranged in that order from an object side to an image side, the rear group including at least one lens unit, wherein intervals between the lens units that are adjacent to each other vary during zooming, and wherein the composite optical element is included in the second lens unit.

18. The optical system according to claim 11, wherein the optical system includes a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, and a rear group that are arranged in that order from an object side to an image side, the rear group including at least one lens unit, wherein intervals between the lens units that are adjacent to each other vary during zooming, and wherein the composite optical element is included in the third lens unit.

19. The optical system according to claim 11, wherein the optical system includes a front group having a positive refractive power, an aperture stop, and a rear group that are arranged in that order from an object side to an image side, and wherein the composite optical element is included in the front group.

20. An imaging apparatus comprising: an optical system; and an image pickup device that receives an image formed by the optical system, wherein the optical system includes: a composite optical element including a glass lens and a resin lens that are joined together, wherein the resin lens has an aspheric shape, and wherein, when Nd is a refractive index of the resin lens, ?d is an Abbe number of the resin lens, and ?gF is a partial dispersion ratio of the resin lens, the following inequalities are satisfied:
1.900<Nd+(0.014??d)<2.045
30.0<?d<35.0
0.6200<?gF+(0.0024??d)<0.6900

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a sectional view of lenses of an optical system according to a first embodiment at the wide-angle end.

[0009] FIGS. 2A and 2B show aberration diagrams of the optical system according to the first embodiment at the wide-angle end and the telephoto end, respectively.

[0010] FIG. 3 is a sectional view of lenses of an optical system according to a second embodiment at the wide-angle end.

[0011] FIGS. 4A and 4B show aberration diagrams of the optical system according to the second embodiment at the wide-angle end and the telephoto end, respectively.

[0012] FIG. 5 is a sectional view of lenses of an optical system according to a third embodiment.

[0013] FIG. 6 show aberration diagrams of the optical system according to the third embodiment.

[0014] FIG. 7 is a sectional view of lenses of an optical system according to a fourth embodiment at the wide-angle end.

[0015] FIGS. 8A and 8B show aberration diagrams of the optical system according to the fourth embodiment at the wide-angle end and the telephoto end, respectively.

[0016] FIG. 9 is a sectional view of lenses of an optical system according to a fifth embodiment at the wide-angle end.

[0017] FIGS. 10A and 10B show aberration diagrams of the optical system according to the fifth embodiment at the wide-angle end and the telephoto end, respectively.

[0018] FIG. 11 is a sectional view of lenses of an optical system according to a sixth embodiment.

[0019] FIG. 12 show aberration diagrams of the optical system according to the sixth embodiment.

[0020] FIG. 13 is a schematic diagram illustrating an imaging apparatus.

DESCRIPTION OF THE EMBODIMENTS

[0021] Optical systems according to embodiments of the present invention and imaging apparatuses including the optical systems will be described with reference to the accompanying drawings.

[0022] FIGS. 1, 3, 5, 7, 9, and 11 are sectional views of optical systems L0 according to first to sixth embodiments. The optical system L0 of each embodiment is an optical system included in an imaging apparatus, such as a digital video camera, a digital still camera, a broadcast camera, a silver-halide film camera, a monitoring camera, or an on-vehicle camera.

[0023] In each sectional view of the lenses, the left side is the object side and the right side is the image side. The optical system L0 of each embodiment may be used as a projection lens of a projector or the like. In such a case, a screen is on the left side and a projection image is on the right side.

[0024] The optical system L0 of each embodiment includes one or more composite optical elements (HB1, HB2, HB3, and HB4) formed by joining a resin lens PL to a glass lens L. Each of the composite optical elements HB1, HB2, HB3, and HB4 may be composed of one glass lens L and one resin lens PL, or be composed of one or more glass lenses L and one or more resin lenses PL.

[0025] In the sectional views of the lenses, the solid-line arrows show loci of movement of lens units during zooming from the wide-angle end to the telephoto end. The lens units move as shown by the dotted-line arrows during focusing from infinity to a close distance.

[0026] In each sectional view of the lenses, STO denotes an aperture stop, and IP denotes an image plane. When the optical system of each embodiment is included in a digital still camera or a digital video camera, an imaging plane of a solid-state image pickup device (photoelectric transducer), such as a CCD sensor or a CMOS sensor, is disposed on the image plane IP. When the optical system of each embodiment is used as an image-capturing optical system of a silver-halide film camera, a photosensitive surface, which corresponds to a film surface, is placed on the image plane IP.

[0027] FIGS. 2A, 4A, 8A, and 10A and FIGS. 2B, 4B, 8B, and 10B show aberration diagrams of the optical systems according to the first, second, fourth, and fifth embodiments at the wide-angle end and the telephoto end, respectively, when an object at infinity is in focus.

[0028] FIGS. 6 and 12 show aberration diagrams of the optical systems according to the third embodiment and the sixth embodiment, respectively, when an object at infinity is in focus.

[0029] In the spherical aberration diagrams, Fno is the F-number, and the amounts of spherical aberrations with respect to the d-line (wavelength 587.6 nm) and the g-line (wavelength 435.8 nm) are shown. In the astigmatism diagrams, S is the amount of aberration on the sagittal image plane, and T is the amount of aberration on the meridional image plane. The distortion diagrams show the amounts of distortions with respect to the d-line. In addition, ? is the imaging half angle of view (?).

[0030] Characteristic structures of the optical systems according to the embodiments will now be described.

[0031] Each embodiment includes one or more composite optical elements (HB1, HB2, HB3, and HB4) obtained by joining a resin lens PL having an aspheric shape to a glass lens L. Each of the composite optical elements HB1, HB2, HB3, and HB4 is configured to satisfy the following inequalities:

1.900<Nd+(0.014??d)<2.045(1)

30.0<?d<35.0(2)

0.6200<?gF+(0.0024??d)<0.6900(3)

[0032] Here, Nd is the refractive index of the resin lens PL, ?d is the Abbe number of the resin lens PL, and ?gF is the partial dispersion ratio of the resin lens PL.

[0033] Nd is the refractive index at the d-line (587.6 nm). When Nd, NF, and NC are the refractive indices at the d-line (wavelength 587.6 nm), the F-line (486.1 nm), and the C-line (656.3 nm), respectively, the Abbe number ?d is expressed as follows:

?d=(Nd?1)/(NF?NC)

[0034] Inequality (1) defines a range of the refractive index of the resin lens PL. When the value of Inequality (1) is below the lower limit, the refractive index of the resin lens PL is too low, and the difference between the thickness of the resin lens PL along the optical axis and the thickness of the resin lens PL in the direction of the optical axis at a high position in the radial direction is too large. Accordingly, the surfaces of the resin lens PL significantly vary in response to temperature variations and moisture absorption, and the optical performance is degraded. When the value of Inequality (1) is above the upper limit, the optical performance significantly varies due to variations in the surfaces of the resin lens PL when the temperature or humidity varies.

[0035] Inequality (2) defines a range of the Abbe number of the resin lens PL. When Inequality (2) is satisfied, the chromatic aberration can be reduced. When the value of Inequality (2) is below the lower limit, the dispersion of the resin lens PL is increased. When the resin lens PL has an aspheric shape, the chromatic spherical aberration and the chromatic field curvature are increased. When the value of Inequality (2) is above the upper limit, the axial chromatic aberration and the lateral chromatic aberration cannot be corrected.

[0036] Inequality (3) defines a range of the partial dispersion ratio of the resin lens PL. When Inequality (3) is satisfied, the effect of correcting the chromatic aberration can be obtained when the resin lens PL has an aspheric shape.

[0037] When the value of Inequality (3) is below the lower limit, the effect of chromatic aberration correction provided by the resin lens PL is reduced at the short-wavelength side (blue side), and the secondary chromatic aberration is likely to be insufficiently corrected. When the value of Inequality (3) is above the upper limit, the partial dispersion ratio of the resin lens PL is increased, and the secondary chromatic aberration is excessively corrected.

[0038] According to the above-described structure, a small, light-weight, high-performance optical system can be realized.

[0039] Preferably, at least one of the upper and lower limits of the numerical range of any of Inequalities (1), (2), and (3) is changed as in Inequalities (1a), (2a), and (3a):

1.950<Nd+(0.014??d)<2.040(1a)

30.2<?d<34.5(2a)

0.6400<?gF+(0.0024??d)<0.6850(3a)

[0040] More preferably, at least one of the upper and lower limits of the numerical range of any of Inequalities (1), (2), and (3) is changed as in Inequalities (1b), (2b), and (3b):

2.000<Nd+(0.014??d)<2.035(1b)

30.4<?d<34.0(2b)

0.6600<?gF+(0.0024??d)<0.6800(3b)

[0041] The structure of the optical system L0 according to each embodiment will now be described.

[0042] The resin from which the resin lens PL is formed can be a photocurable resin. When a photocurable resin is used, the resin lens PL can be formed on the glass lens L at a lower temperature compared to when a thermosetting resin is used. Therefore, the resin lens PL is not easily deformed and can be formed in a desired shape, so that the optical system L0 can have a high optical performance.

[0043] The composite optical elements HB1, HB2, HB3, and HB4 can be disposed on the image side of a lens closest to the object side in the optical system L0. The photocurable resin tends to have a low light stability due to the influence of a photopolymerization initiator, and the transmittance thereof at the short-wavelength side (blue side) is easily reduced due to yellowing caused by exposure to strong light for a long time.

[0044] When the transmittance at the short-wavelength side (blue side) is reduced, color reproducibility for the object is reduced. To obtain an imaging optical system having stable color reproducibility for a long period of time, a glass lens can be disposed on the object side of the composite optical elements HB1, HB2, HB3, and HB4 to reduce yellowing.

[0045] The optical system L0 includes a front group, an aperture stop, and a rear group arranged in that order from the object side, and one or more of the composite optical elements HB1, HB2, HB3, and HB4 can be included in the front group. When one or more of the composite optical elements HB1, HB2, HB3, and HB4 is included in the front group, the aberrations can be appropriately corrected.

[0046] Inequalities that can be satisfied by the optical system L0 of each embodiment will now be described.

[0047] The optical system L0 of each embodiment can satisfy one or more of the following inequalities:

1.0<Tmax/Tmin<10.0(4)

3<Tg/Tp<200(5)

|fg/fp|<0.30(6)

?<7.5[%](7)

60?10.sup.?6<?<100?10.sup.?6[1/? C.](8)

0.98<Ndg/Nd<1.4(9)

35.0<?dg<100.0(10)

?w<0.50[%](11)

[0048] Here, Tmax and Tmin are respectively the maximum thickness and the minimum thickness of the resin lens PL in the direction of the optical axis within the effective diameter, Tg is the thickness of the glass lens L along the optical axis, Tp is the thickness of the resin lens PL along the optical axis, fg is the focal length of the glass lens L, and fp is the focal length of the resin lens PL.

[0049] In addition, R is a curing shrinkage ratio of the resin lens PL. The curing shrinkage ratio is defined as follows:

Curing Shrinkage Ratio (%)=100?(specific gravity after curing?specific gravity before curing)/specific gravity after curing.

[0050] In addition, a is the coefficient of linear expansion of the resin lens PL, Ndg is the refractive index of the glass lens L, Nd is the refractive index of the resin lens PL, and ?dg is the Abbe number of the glass lens PL.

[0051] In addition, aw is a hygroscopic expansion ratio of the resin lens PL. The hygroscopic expansion ratio is defined as follows:

Hygroscopic Expansion Ratio (%)=100?(thickness after hygroscopic expansion?thickness before hygroscopic expansion)/thickness after hygroscopic expansion.

[0052] Thickness variations caused when the humidity is changed from 0% to 90% in an environment at 60? C. are evaluated by using a humidity-controlled thermomechanical analyzer (TMA) for the measurement.

[0053] Inequality (4) defines a range of the thickness of the resin lens PL in the direction of the optical axis. When the value of Inequality (4) is above the upper limit, the thickness deviation ratio of the resin lens PL is too high, and surfaces are easily deformed when the temperature or humidity varies. When the value of Inequality (4) is below the lower limit, the amount of asphericity is too small and the aberrations cannot be easily corrected.

[0054] Inequality (5) defines a range of the ratio between the thickness of the glass lens L and the thickness of the resin lens PL along the optical axis. When the value of Inequality (5) is above the upper limit, the thickness of the resin lens PL is too small, and the desired amount of asphericity cannot be obtained. When the value of Inequality (5) is below the lower limit, the thickness of the resin lens PL is too large, and the transmittance at the short-wavelength side (blue side) is reduced.

[0055] Inequality (6) defines a range of the ratio between the focal length of the glass lens L and the focal length of the resin lens PL. When the value of Inequality (6) is above the upper limit, the refractive power of the resin lens PL is too strong, and surfaces are easily deformed when the temperature or humidity varies.

[0056] Inequality (7) defines a range of the curing shrinkage ratio of the resin lens PL. The photocurable resin is generally applied dropwise onto an aspherical mold and a base lens and placed along the aspherical mold, and then UV curing is performed. When the curing shrinkage ratio is large, the surface shapes change after the curing process, and the desired surface accuracy cannot be easily obtained.

[0057] When Inequality (7) is satisfied, the changes in shapes due to the curing process are reduced, and the surface accuracy can be increased.

[0058] Inequality (8) defines a range of the coefficient of linear expansion of the resin lens PL. When the value is above the upper limit, the surfaces of the resin lens PL are easily deformed in response to a temperature change. When the value is below the lower limit, the difference in coefficient of linear expansion between the glass lens L and the resin lens PL increases. As a result, stress applied to the joining surfaces increases, and the composite optical elements HB1, HB2, HB3, and HB4 easily break.

[0059] Inequality (9) defines a range of the ratio between the refractive index of the glass lens L and the refractive index of the resin lens PL. When the value of Inequality (9) is above the upper limit, the refractive index of the resin lens PL is too low and the curvature needs to be increased to obtain the desired refractive power. Accordingly, the surfaces are easily deformed when the temperature or humidity varies. When the value is below the lower limit, the refractive index of the glass lens L is too low, and the curvature needs to be increased to obtain the desired refractive power. As a result, the aberrations cannot be easily corrected.

[0060] Inequality (10) defines a range of the Abbe number of the glass lens L. When the value of Inequality (10) is above the upper limit, the difference in Abbe number between the resin lens PL and the glass lens L is too large, and the primary axial chromatic aberration and the primary lateral chromatic aberration are increased. When the value is below the lower limit, the Abbe number of the glass lens L is too small, and the partial dispersion ratio of the glass lens L is increased. Accordingly, the secondary axial chromatic aberration and the secondary lateral chromatic aberration are increased.

[0061] Inequality (11) defines a range of the hygroscopic expansion ratio of the resin lens PL. When the value of Inequality (11) is above the upper limit, the expansion of the resin lens PL due to moisture absorption is increased, and the surface shapes are significantly changed.

[0062] Preferably, at least one of the upper and lower limits of Inequalities (4) to (11) is set as in numerical ranges given below:

1.0<Tmax/Tmin<7.0(4a)

4<Tg/Tp<150(5a)

|fg/fp|<0.25(6a)

?<6.8[%](7a)

65?10.sup.?6<?<95?10.sup.?6[1/? C.](8a)

1.0<Ndg/Nd<1.3(9a)

37.5<?dg<80.0(10a)

?w<0.45[%](11a)

[0063] More preferably, at least one of the upper and lower limits of Inequalities (4) to (11) is set as in numerical ranges given below:

1.0<Tmax/Tmin<5.0(4b)

5<Tg/Tp<100(5b)

|fg/fp|<0.20(6b)

?<6.5[%](7b)

70?10.sup.?6<?<90?10.sup.?6[1/? C.](8b)

1.0<Ndg/Nd<1.2(9b)

40.0<?dg<60.0(10b)

?w<0.40[%](11b)

[0064] Detailed structures of the optical system L0 of each embodiment will now be described.

[0065] The materials of resin lenses PL1, PL11, PL12, and PL13 are material 1 shown in Table 1. The material of a resin lens PL2 is material 2 in Table 1. The materials of resin lenses PL3, PL31, and PL32 are material 3 in Table 1.

First Embodiment

[0066] The optical system L0 according to the first embodiment is a zoom lens including first to seventh lens units having positive, negative, positive, negative, positive, negative, and positive refractive powers and arranged in that order from the object side to the image side. During zooming, the intervals between the lens units vary. Since the first lens unit has a positive refractive power, the principal point can be disposed on the object side, and the overall length of the lenses in the optical system L0 can be reduced as a result. The second lens unit has a negative refractive power, and the interval between the first and second lens units is increased to change the magnification. The third and following lens units include lens units having a positive refractive power and lens units having a negative refractive power, so that variations in the aberrations that occur during zooming can be reduced.

[0067] The fourth lens unit moves during focusing so that high-speed focusing can be performed.

[0068] In the embodiments, the materials of the resin lenses PL included in the composite optical elements HB1, HB2, HB3, and HB4 are the materials shown in Table 1. Here, material 1 has a higher dispersion and a higher partial dispersion ratio than those of material 2. Material 2 has a higher dispersion and a higher partial dispersion ratio than those of material 3.

[0069] In the optical system L0 according to the first embodiment, a resin lens PL1 is disposed on the object side of a glass lens L41. The resin lens PL1 has a positive refractive power, the glass lens L41 has a negative refractive power, and the fourth lens unit has a negative refractive power. Since the resin lens PL1 is formed of material 1 having a high dispersion, the chromatic aberration generated in the fourth lens unit can be reduced. In addition, the resin lens PL1 has an aspheric shape, so that the spherical aberration at the telephoto end, in particular, can be corrected.

[0070] Since the resin lens PL1 is included in the fourth lens unit, the aberrations that vary during focusing can be reduced.

[0071] A resin lens PL3 is disposed on the object side of a glass lens L21. The resin lens PL3 has a positive refractive power, so that the lateral chromatic aberration generated in the second lens unit, in particular, can be reduced. In addition, the resin lens PL3 has an aspheric shape, so that distortion at the wide-angle end, in particular, can be corrected.

Second Embodiment

[0072] The optical system L0 according to the second embodiment is a zoom lens including first to fourth lens units having negative, positive, negative, and positive refractive powers and arranged in that order from the object side to the image side. During zooming, the intervals between the lens units vary. Since the first lens unit has a negative refractive power, the diameter of the first lens unit can be reduced in a wide-angle zoom lens. Since the second lens unit has a positive refractive power, the diameters of the lens units disposed on the image side of the second lens unit can be reduced. The third lens unit moves during focusing, so that high-speed focusing speed can be performed. Since the fourth lens unit has a positive refractive power, the principal point of the optical system L0 can be disposed on the image side, and a desired back focal length can be obtained.

[0073] A resin lens PL2 is disposed on the object side of a glass lens L12. The resin lens PL2 has an aspheric shape and is included in the first lens unit, so that the distortion at the wide-angle end, in particular, can be corrected.

[0074] A resin lens PL3 is disposed on the object side of a glass lens L21. The resin lens PL3 has a negative refractive power, so that the axial chromatic aberration generated in the second lens unit, in particular, can be corrected. In addition, the resin lens PL3 has an aspheric shape, so that the spherical aberration at the telephoto end, in particular, can be corrected.

[0075] A resin lens PL1 is disposed on the object side of a glass lens L31. The resin lens PL1 has an aspheric shape and is included in the third lens unit, so that the aberrations that vary during focusing can be reduced.

Third Embodiment

[0076] The optical system L0 according to the third embodiment is an optical system including first to fourth lens units having positive, positive, positive, and negative refractive powers and arranged in that order from the object side to the image side. During focusing, the second lens unit and the third lens unit move in the direction of the optical axis along different loci. An aperture stop is included in the second lens unit, so that symmetry of the optical system is improved and the aberrations generated in the first to third lens units are reduced. The combined focal length of all of the lenses disposed on the object side of the aperture stop is positive, so that the diameter of the axial light incident on the lenses on the image side of the aperture stop is reduced, and the sizes of the lenses on the image side of the aperture stop are reduced. Since the fourth lens unit having a negative refractive power is provided, the principal point of the optical system L0 is disposed on the object side, and the size of the optical system L0 is reduced.

[0077] A resin lens PL1 is disposed on the object side of a glass lens L14. The resin lens PL1 has an aspheric shape and is included in the first lens unit, so that the spherical aberration and coma aberration, in particular, can be corrected.

[0078] A resin lens PL3 made of material 3 is disposed on the object side of a glass lens L31. The resin lens PL3 has an aspheric shape and is included in the third lens unit, so that the aberrations that vary during focusing can be reduced.

Fourth Embodiment

[0079] The optical system L0 according to the fourth embodiment is a zoom lens including first to seventh lens units having positive, negative, positive, positive, negative, negative, and positive refractive powers and arranged in that order from the object side to the image side. During zooming, the intervals between the lens units vary. During focusing, the fifth lens unit and the sixth lens unit move in the direction of the optical axis along different loci.

[0080] A resin lens PL31 is disposed on the object side of a glass lens L21. The resin lens PL31 has a positive refractive power and reduces, in particular, the lateral chromatic aberration generated in the second lens unit at the wide-angle end.

[0081] A resin lens PL1 is disposed on the object side of a glass lens L32. The resin lens PL1 has an aspheric shape and is included in the third lens unit, so that the spherical aberration at the wide-angle end, in particular, can be corrected.

[0082] A resin lens PL32 is disposed on the object side of a glass lens L61. The resin lens PL32 has an aspheric shape and is included in the sixth lens unit, so that the aberrations that vary during focusing can be reduced.

Fifth Embodiment

[0083] The optical system L0 according to the fifth embodiment is a zoom lens including first to seventh lens units having negative, positive, positive, negative, positive, negative, and positive refractive powers and arranged in that order from the object side to the image side. During zooming, the intervals between the lens units vary. During focusing, the fourth lens unit and the sixth lens unit move in the direction of the optical axis along different loci.

[0084] A resin lens PL31 is disposed on the object side of a glass lens L13. The resin lens PL31 has an aspheric shape and is included in the first lens unit, so that the distortion at the wide-angle end, in particular, can be corrected.

[0085] A resin lens PL11 is disposed on the object side of a glass lens L21. The resin lens PL11 has an aspheric shape and is included in the second lens unit, so that the spherical aberration at the wide-angle end, in particular, can be corrected.

[0086] A resin lens PL32 is disposed on the image side of a glass lens L51. The resin lens PL32 has a negative refractive power and reduces, in particular, the lateral chromatic aberration generated in the fifth lens unit at the wide-angle end.

[0087] A resin lens PL12 is disposed on the object side of a glass lens L61. The resin lens PL12 has an aspheric shape and is included in the sixth lens unit, so that the aberrations that vary during focusing can be reduced.

Sixth Embodiment

[0088] The optical system L0 according to the sixth embodiment is an optical system including first to fifth lens units having positive, negative, positive, negative, and positive refractive powers and arranged in that order from the object side to the image side. During focusing, the second lens unit and the fourth lens unit move in the direction of the optical axis. An aperture stop is included in the third lens unit, so that the size of the aperture stop can be reduced. The combined focal length of all of the lenses disposed on the object side of the aperture stop is positive, so that the diameter of the axial light incident on the lenses on the image side of the aperture stop is reduced, and the sizes of the lenses on the image side of the aperture stop are reduced. During focusing, the second lens unit may move while the fourth lens unit is stationary.

[0089] A resin lens PL11 is disposed on the object side of a glass lens L12. The resin lens PL11 on the glass lens L12 has an aspheric shape and is included in the first lens unit, so that the spherical aberration, in particular, can be corrected.

[0090] A resin lens PL12 is disposed on the image side of a glass lens L33. The resin lens PL12 has a negative refractive power and reduces, in particular, the axial chromatic aberration.

[0091] A resin lens PL13 is disposed on the object side of a glass lens L41. The resin lens PL13 has an aspheric shape and is included in the fourth lens unit, so that the aberrations that vary during focusing can be reduced.

[0092] Although the optical system L0 according to each of the first to sixth embodiments is structured such that some of the lenses included therein are the composite optical elements HB1, HB2, HB3, and HB4, the optical system L0 may be composed only of the composite optical elements HB1, HB2, HB3, and HB4.

[0093] The resin lens may include impurities as long as the main component thereof is resin. The glass lens may include impurities as long as the main component thereof is glass.

[0094] First to sixth numerical examples corresponding to the first to sixth embodiments will now be described.

[0095] In surface data of each numerical example, OBJ represents the object side. Also, d (mm) is the interval along the axis (distance along the optical axis) between the m.sup.th and (m+1).sup.th surfaces, where m is the number of each surface counted from the light incident side.

[0096] BF represents the back focal length. The unit of the half angle of view is the degree. Materials 1 to 3 correspond to materials 1 to 3 shown in Table 1.

[0097] The symbol * is attached to the right side of the surface number when the corresponding optical surface is an aspheric surface. When X is the displacement from the vertex of a surface in the direction of the optical axis, h is the height from the optical axis in a direction perpendicular to the optical axis, r is the paraxial radius of curvature, K is the conic constant, and A, B, C, D, E, and F are aspheric coefficients of the respective orders, an aspheric shape can be represented by the following equation:

x=(h.sup.2/r)/[1+{1?(1+K)(h/r).sup.2}.sup.1/2]+A?h.sup.4+B?h.sup.6+C?h.sup.8+D?h.sup.10+E?h.sup.12+F?h.sup.14

[0098] For each of the aspheric coefficients, e?XX means ?10?XX.

First Numerical Example

[0099]

TABLE-US-00001 Unit of Measure mm Unit Surface Number Effective Diameter Radius of Curvature d Material Nd ?d OBJ 1 1 56.22 109.5582 1.2000 EFDS1W 1.92286 20.88 2 52.19 58.8628 8.0000 SLAH66 1.77250 49.60 3 50.51 ?807.8867 (1.2000) 2 4* 32.63 46.3012 0.1200 Material 3 1.57844 32.31 5 32.32 48.5957 1.0000 SNBM51 1.61340 44.27 6 24.49 15.6877 7.5400 7 24.24 ?49.7225 0.8000 SLAL7Q 1.65160 58.54 8 21.79 26.1985 0.3000 9 21.71 25.3957 4.3000 SNBH56 1.85478 24.80 10 20.99 ?162.7544 1.3500 11 20.88 ?35.0984 0.8000 SLAH66 1.77250 49.60 12 20.45 ?264.6203 (14.7183) 3 13 18.87 34.4152 3.7500 SBSM16 1.62041 60.29 14 18.90 ?47.7999 (4.4290) 4 15* 18.35 ?28.2385 0.1000 Material 1 1.58946 30.62 16 18.36 ?28.1648 0.8000 SLAH66 1.77250 49.60 17 19.09 85.3680 (2.9280) 5 s18 11.14 Infinity 0.3000 19 21.56 21.6525 6.3000 SFPL51 1.49700 81.54 20 21.56 ?41.4868 0.8000 SNBH56 1.85478 24.80 21 21.70 ?73.4806 0.3000 22 21.44 20.8538 5.9000 SFPL51 1.49700 81.54 23 20.60 ?57.2878 (1.6973) 6 24 19.03 ?32.8448 2.5000 EFDS1W 1.92286 20.88 25 18.92 ?24.6748 0.8000 NBFD29 1.77047 29.74 26 18.57 520.0360 (1.8567) 7 27 18.41 21.7440 2.7500 SLAH51 1.78590 44.20 28 18.02 44.4433 1.9000 29* 18.03 60.3557 1.2000 SLAH65V 1.80400 46.58 30* 18.08 50.2598 6.7137 31 19.04 ?14.0878 1.2000 SFPM5 1.55200 70.70 32 20.94 ?21.4012 (20.4643) IMG Aspheric Surface Data Surface 4 r = 4.63012e+01 K = 0.00000e+00 A = ?1.22410e?06 B = ?1.69358e?09 C = ?5.41969e?11 D = 1.88636e?13 E = ?3.12307e?16 F = 0.00000e+00 Surface 15 r = ?2.82385e+01 K = 0.00000e+00 A = 1.32862e?06 B = 1.95072e?09 C = ?4.31354e?11 D = 5.25362e?13 E = ?7.48925e?15 F = 0.00000e+00 Surface 29 r = 6.03557e+01 K = 0.00000e+00 A = ?5.44960e?05 B = ?7.47516e?08 C = 1.76609e?09 D = ?8.16025e?12 E = 0.00000e+00 F = 0.00000e+00 Surface 30 r = 5.02598e+01 K = 0.00000e+00 A = ?5.26123e?07 B = ?4.71521e?09 C = 1.67048e?09 D = ?7.01370e?12 E = 0.00000e+00 F = 0.00000e+00 Various Data Wide Angle Intermediate Telephoto Focal Length 24.60 35.00 67.90 F-Number 4.12 4.12 4.12 Half Angle of View 41.33 31.72 17.67 Real Image Height 19.39 21.41 21.64 Overall Length 108.50 114.20 142.13 BF 20.95 29.00 50.49 Interval Data Wide Angle Intermediate Telephoto Wide Angle Close-Up Intermediate Close-Up Telephoto Close-Up d0 Infinity Infinity Infinity 190.0037 184.3079 156.3736 d3 1.2000 6.2051 19.6195 d12 14.7183 7.5639 1.0000 d14 4.4290 4.6576 6.2219 2.1300 2.3769 3.5021 d17 2.9280 2.6994 1.1351 5.2371 5.0005 4.0747 d23 1.6973 1.9626 2.3469 d26 1.8567 1.3851 0.5926 d32 20.4643 28.5451 49.9385 Unit Data Unit Start Surface Focal Length B1 1 146.8806 B2 4 ?20.7586 B3 13 32.8245 B4 15 ?27.3564 B5 18 18.9031 B6 24 ?43.0176 B7 27 137.0246

Second Numerical Example

[0100]

TABLE-US-00002 Unit of Measure mm Unit Surface Number Effective Diameter Radius of Curvature d Material Nd ?d OBJ 1 1 26.90 41.7026 1.2000 SBSM16 1.62041 60.29 2 21.40 13.4105 8.0000 3* 20.50 ?39.5335 0.1000 Material 2 1.58212 31.72 4 20.48 ?39.9499 1.0000 SLAL12Q 1.67790 55.35 5 20.02 55.5002 0.4650 6 20.04 29.4638 2.3500 STIH53 1.84666 23.78 7 19.66 82.0347 (24.7972) 2 8* 16.66 25.2835 0.1000 Material 3 1.57844 32.31 9 16.64 26.2340 2.8000 SLAL14 1.69680 55.53 10 16.55 ?185.6544 0.3000 11 16.28 20.2547 3.9000 SFPL51 1.49700 81.54 12 15.91 ?31.0915 0.6000 STIM22 1.64769 33.79 13 15.58 ?115.4026 1.5000 s14 7.51 Infinity 1.5000 15 13.89 50.0711 0.6000 NBFD29 1.77047 29.74 16 13.19 12.8607 1.6000 17 13.44 21.4799 2.7500 SLAL14 1.69680 55.53 18 13.32 ?49.7270 (1.5000) 3 19* 11.05 ?235.5077 0.1000 Material 1 1.58946 30.62 20 11.07 ?195.1432 0.6000 SBSM16 1.62041 60.29 21 11.35 18.6696 (6.0712) 4 22 24.55 683.9337 4.0000 SBSM15 1.62299 58.16 23 25.00 ?29.0368 17.6666 IMG Aspheric Shape Surface 3 r = ?3.95335e+01 K = 0.00000e+00 A = 3.72175e?06 B = ?3.62012e?08 C = 2.89635e?10 D = ?1.85987e?12 E = 4.91437e?15 F = 0.00000e+00 Surface 8 r = 2.52835e+01 K = 0.00000e+00 A = ?2.21536e?05 B = 7.40283e?08 C = ?9.30185e?10 D = 4.69479e?12 E = 0.00000e+00 F = 0.00000e+00 Surface 19 r = ?2.35508e+02 K = 0.00000e+00 A = ?2.22656e?05 B = 8.28531e?08 C = 7.05625e?09 D = ?9.52391e?11 E = 0.00000e+00 F = 0.00000e+00 Various Data Wide Angle Intermediate Telephoto Focal Length 15.30 30.00 45.00 F-Number 4.12 4.12 4.12 Half Angle of View 41.68 24.91 16.51 Real Image Height 11.60 13.65 13.65 Overall Length 83.50 83.50 83.50 BF 17.67 17.67 17.67 Interval Data Wide Angle Intermediate Telephoto Wide Angle Close-Up Intermediate Close-Up Telephoto Close-Up d0 Infinity Infinity Infinity 215.0042 215.0040 215.0175 d18 1.5000 5.6039 12.7178 2.1066 7.2481 16.5410 d21 6.0712 17.8923 18.6010 5.4947 16.3474 14.9773 Unit Data Unit Start Surface Focal Length B1 1 ?22.7329 B2 8 18.8764 B3 19 ?27.8314 B4 22 44.8069

Third Numerical Example

[0101]

TABLE-US-00003 Unit of Measure mm Unit Surface Number Effective Diameter Radius of Curvature d Material Nd ?d OBJ 1 1 37.13 ?71.3044 1.0000 STIM8 1.59551 39.24 2 37.18 99.3313 3.8633 3 37.51 ?159.2435 8.0103 SLAH96 1.76385 48.49 4 38.18 ?30.1079 1.2000 NBFD29 1.77047 29.74 5 40.98 172.6911 0.2000 6* 43.77 60.8144 0.1500 Material 1 1.58946 30.62 7 43.83 65.3234 8.1487 SLAH52Q 1.79952 42.24 8 44.23 ?119.5223 0.1000 9 44.26 ?2096.0460 3.7235 SNPH4 1.89286 20.36 10 44.30 ?121.2291 (7.5675) 2 11 39.91 43.2649 4.2677 TAFD55W 2.00100 29.13 12 38.65 78.6856 3.9101 s13 37.41 Infinity 7.7477 14 33.19 ?53.8580 1.0000 SNBH8 1.72047 34.71 15 32.07 32.3216 5.6097 SFPL55 1.43875 94.66 16 32.17 288.2573 3.3230 17 33.06 41.2838 8.3078 SFPM3 1.53775 74.70 18 32.90 ?54.2552 (8.5403) 3 19* 33.48 130.3947 0.3000 Material 3 1.57844 32.31 20 33.51 572.6917 5.2480 SLAH65V 1.80400 46.58 21 33.69 ?45.9119 1.2000 STIM35 1.69895 30.13 22 33.96 ?2124.8955 (1.5000) 4 23 34.32 ?2142.3828 6.8998 SLAH93 1.90525 35.04 24 34.43 ?33.7063 1.2000 STIM22 1.64769 33.79 25 33.44 97.4899 5.7826 26* 33.44 ?39.4877 1.2000 SNSL3 1.51823 58.90 27 35.27 ?620.6618 13.5127 IMG Aspheric Surface Data Surface 6 r = 6.08144e+01 K = 0.00000e+00 A = ?1.54852e?06 B = 8.52924e?10 C = ?3.40772e?12 D = 6.10886e?15 E = ?4.28512e?18 F = 0.00000e+00 Surface 19 r = 1.30395e+02 K = 0.00000e+00 A = ?8.23122e?06 B = ?5.74189e?09 C = ?6.80330e?12 D = ?1.96932e?14 E = 2.97689e?17 F = 0.00000e+00 Surface 26 r = ?3.94877e+01 K = 0.00000e+00 A = ?5.42380e?06 B = 9.92989e?09 C = ?1.59142e?11 D = ?1.07744e?14 E = 0.00000e+00 F = 0.00000e+00 Various Data Focal Length 50.03 F-Number 1.44 Half Angle of View 23.39 Real Image Height 21.64 Overall Length 113.51 BF 13.51 Interval Data Object at Infinity Distance 2 Distance 3 d0 Infinity 2382 282 d11 7.5675 6.7335 1.0000 d19 8.5403 8.5170 8.4611 d23 1.5000 2.3576 8.1468 Unit Data Unit Start Surface Focal Length B1 1 148.4010 B2 11 86.5174 B3 19 135.0250 B4 23 ?86.3586

Fourth Numerical Example

[0102]

TABLE-US-00004 Unit of Measure mm Unit Surface Number Effective Diameter Radius of Curvature d Material Nd ?d OBJ 1 1 58.29 87.9007 1.3000 SLAH92 1.89190 37.13 2 56.08 57.1735 8.1500 SFPL51 1.49700 81.54 3 55.14 317.6192 0.2000 4 52.73 73.7099 7.0000 SFPM4 1.52841 76.45 5 51.73 ?2592.2438 1.2000 2 6* 35.12 6227.6782 0.1000 Material 3 1.57844 32.31 7 34.98 482.5262 1.4000 SLAH65V 1.80400 46.58 8 28.15 23.3149 7.4000 9 27.73 ?44.4217 1.2000 SLAL7Q 1.65160 58.54 10 27.00 82.7114 0.9000 11 26.99 53.6451 4.8000 SNBH56 1.85478 24.80 12 26.51 ?83.7860 2.6700 13 26.21 ?27.5416 0.8000 SLAL14 1.69680 55.53 14 26.50 ?53.7315 34.1114 3 s15 23.27 Infinity 1.0000 16 24.92 29.4374 4.9000 NBFD29 1.77047 29.74 17 24.58 ?648.9230 0.2000 18* 23.75 32.9912 0.1000 Material 1 1.58946 30.62 19 23.68 33.0662 5.0000 FCD600 1.59410 60.47 20 22.91 ?55.1172 0.8000 TAFD55W 2.00100 29.13 21 22.11 70.6777 0.7000 22 21.61 27.7554 0.8000 TAFD55W 2.00100 29.13 23 20.33 15.5132 5.2000 FCD600 1.59410 60.47 24 19.78 80.7859 0.3000 25 19.59 48.8358 0.8000 SNBH56 1.85478 24.80 26 18.96 22.7910 4.8253 4 27* 19.12 58.8973 2.1000 SFPM3 1.53775 74.70 28 19.14 ?180.8280 1.0500 29 19.13 ?42.0993 3.2500 STIM25 1.67270 32.10 30 19.33 ?16.5048 0.8000 SLAH59 1.81600 46.62 31 20.07 ?40.0327 0.2000 32 20.51 46.2730 4.7500 SFPM3 1.53775 74.70 33 20.66 ?34.1487 1.2000 5 34 20.07 53.4258 2.5000 STIH53 1.84666 23.78 35 19.77 ?271.7993 0.8000 SNBH8 1.72047 34.71 36 19.06 22.1453 16.6976 6 37* 23.61 ?22.9947 0.2000 Material 3 1.57844 32.31 38 23.68 ?23.6455 1.0000 SLAM3 1.71700 47.93 39 25.84 ?83.7538 1.9331 7 40 35.44 ?474.0650 3.8000 TAFD37A 1.90043 37.37 41 36.00 ?64.5532 13.5000 IMG Aspheric Surface Data Surface 6 r = 6.22768e+03 K = 0.00000e+00 A = 3.18688e?06 B = ?1.17842e?09 C = ?3.03074e?13 D = 9.55414e?15 E = 0.00000e+00 F = 0.00000e+00 Surface 18 r = 3.29912e+01 K = 0.00000e+00 A = ?3.03190e?06 B = ?3.20647e?09 C = 5.27457e?13 D = 0.00000e+00 E = 0.00000e+00 F = 0.00000e+00 Surface 27 r = 5.88973e+01 K = 0.00000e+00 A = ?1.37808e?05 B = ?3.03143e?10 C = ?4.04786e?12 D = ?7.63644e?14 E = 0.00000e+00 F = 0.00000e+00 Surface 37 r = ?2.29947e+01 K = 0.00000e+00 A = 6.43299e?06 B = 1.57962e?08 C = ?6.68878e?11 D = 7.97465e?13 E = ?2.33566e?15 F = 0.00000e+00 Wide Angle Intermediate Telephoto Focal Length 28.40 85.00 197.00 F-Number 2.90 4.76 5.70 Half Angle of View 37.30 14.28 6.27 Real Image Height 18.98 21.64 21.64 Overall Length 151.14 179.02 220.00 BF 13.50 27.15 47.04 Interval Data Wide Angle Intermediate Telephoto Wide Angle Close-Up Intermediate Close-Up Telephoto Close-Up d0 Infinity Infinity Infinity 348.8972 601.0150 559.9984 d6 1.2000 23.7358 48.0319 1.2000 23.7358 48.0319 d15 34.1114 10.2408 1.5000 34.1114 10.2408 1.5000 d27 4.8253 4.0847 2.5631 4.8253 4.0847 2.5631 d35 1.2000 4.7733 1.5000 1.5781 7.0147 9.9353 d38 16.6976 15.9567 20.6014 18.0753 14.9210 13.4958 d41 1.9331 15.4058 21.0974 0.3000 14.2698 19.9248 d43 13.5000 27.1474 47.0460 13.5000 27.1474 47.0460 Unit Data Unit Start Surface Focal Length B1 1 111.8515 B2 7 ?22.4552 B3 16 51.7920 B4 28 29.3235 B5 36 ?65.4137 B6 39 ?44.8606 B7 42 82.6293

Fifth Numerical Example

[0103]

TABLE-US-00005 Unit of Measure mm Unit Surface Number Effective Diameter Radius of Curvature d Material Nd ?d OBJ 1 1 47.50 75.4202 1.5000 SLAL14 1.69680 55.53 2 38.06 24.0812 6.4000 3 38.30 72.4298 1.8000 SFPM2 1.59522 67.73 4 35.75 36.5684 9.1000 5* 34.97 ?62.2582 0.1500 Material 3 1.57844 32.31 6 34.96 ?63.2735 1.4000 SFPM2 1.59522 67.73 7 34.89 ?1220.0808 0.3000 8 34.78 49.6025 3.3000 SNBH56 1.85478 24.80 9 34.34 107.2344 42.9312 2 10* 23.59 52.2174 0.1500 Material 1 1.58946 30.62 11 23.57 56.8208 3.0000 SLAL14 1.69680 55.53 12 23.46 ?179.1826 4.5979 3 13 23.53 31.3366 4.8500 SFPL55 1.43875 94.66 14 23.21 ?64.8202 1.0000 s15 17.46 Infinity 1.0000 16 21.05 35.5136 3.1000 SFPL51 1.49700 81.54 17 20.34 ?562.3608 1.0000 STIH4 1.75520 27.51 18 18.97 21.3655 5.1493 4 19 18.98 38.0228 3.8000 STIH53 1.84666 23.78 20 18.65 ?37.5904 1.0000 NBFD29 1.77047 29.74 21 18.14 23.6218 3.9538 5 22 19.37 35.5322 3.6500 SFPM2 1.59522 67.73 23 19.78 ?61.5322 0.1000 Material 3 1.57844 32.31 24* 19.81 ?63.9501 1.2000 6 25* 22.74 71.3543 0.1000 Material 1 1.58946 30.62 26 22.75 69.1508 1.0000 SBSM28 1.61772 49.81 27 22.85 26.0982 4.6400 7 28 35.56 409.5688 3.1000 SBSM16 1.62041 60.29 29 36.00 ?134.9423 21.430 IMG Aspheric Surface Data Surface 5 r = ?6.22582e+01 K = 0.00000e+00 A = 9.42990e?08 B = ?6.31667e?09 C = 4.68141e?11 D = ?1.38137e?13 E = 1.52549e?16 F = 0.00000e+00 Surface 10 r = 5.22174e+01 K = 0.00000e+00 A = ?8.11324e?06 B = ?7.25252e?09 C = 4.88156e?11 D = ?1.72295e?13 E = 0.00000e+00 F = 0.00000e+00 Surface 24 r = ?6.39501e+01 K = 0.00000e+00 A = ?2.52047e?06 B = ?3.53338e?08 C = 8.14520e?10 D = ?7.50083e?12 E = 2.46233e?14 F = 0.00000e+00 Surface 25 r = 7.13543e+01 K = 0.00000e+00 A = ?6.97393e?06 B = 2.38504e?08 C = ?1.74049e?10 D = 5.35161e?13 E = 0.00000e+00 F = 0.00000e+00 Wide Angle Intermediate Telephoto Focal Length 21.00 40.00 60.00 F-number 2.90 3.50 4.10 Half Angle of View 45.79 28.39 19.29 Real Image Height 18.37 21.62 21.62 Overall Length 135.70 120.59 126.50 BF 22.43 22.43 22.43 Interval Data Wide Angle Intermediate Telephoto Wide Angle Close-Up Intermediate Close-Up Telephoto Close-Up d0 Infinity Infinity Infinity 364 379 373 d9 42.9312 11.3047 1.2000 42.9312 11.3047 1.2000 d12 4.5979 3.3956 0.7525 4.5979 3.3956 0.7525 d18 5.1493 1.7299 1.5986 7.0332 3.6315 3.6365 d21 3.9538 7.3734 7.5043 2.0700 5.4721 5.4661 d24 1.2000 9.4431 13.1223 2.0166 12.7062 18.9182 d27 4.6400 14.2782 29.0936 3.8735 11.0850 23.3778 Unit Data Unit Start Surface Focal Length B1 1 ?35.5880 B2 10 58.9288 B3 13 271.4136 B4 19 ?154.4306 B5 22 38.9067 B6 25 ?67.2928 B7 28 163.9594

Sixth Numerical Example

[0104]

TABLE-US-00006 Unit of Measure mm Unit Surface Number Effective Diameter Radius of Curvature d Material Nd ?d OBJ 1 1 136.00 344.3393 9.8500 SBSM25 1.65844 50.88 2 135.42 9919.9769 0.2000 3* 132.15 181.3545 0.2000 Material 1 1.51450 51.97 4 132.09 185.9490 9.1000 SFPL51 1.49700 81.54 5 130.83 358.1698 125.1400 6 75.81 140.6255 5.2500 FDS18W 1.94595 17.98 7 74.79 344.6495 1.0000 8 68.19 65.0400 12.6000 CAF2 1.43384 95.16 9 65.55 5892.6284 0.1500 10 64.10 477.7687 1.8500 SNBH56 1.85478 24.80 11 56.54 43.8041 13.6000 SFPL55 1.43875 94.66 12 55.00 1194.8566 10.0796 2 13 45.00 158.5665 1.3500 SNBH56 1.85478 24.80 14 42.96 58.4684 32.8230 3 15 33.69 1e+18 1.0000 16 32.98 115.2657 1.2000 SLAL14 1.69680 55.53 17 32.03 43.3861 6.0000 SFPL55 1.43875 94.66 18 31.52 ?248.0207 1.0000 s19 30.90 1e+18 3.2700 20 29.85 107.3960 1.2000 SLAH66 1.77250 49.60 21 28.97 45.1591 0.1500 Material 1 1.51450 51.97 22* 28.91 43.9923 3.2500 23 28.90 ?141.6322 1.2000 SBAL35 1.58913 61.13 24 28.96 52.9991 3.5000 SNBH56 1.85478 24.80 25 28.83 120.0135 1.2700 26 29.15 65.3167 12.0000 STIH14 1.76182 26.52 27 29.29 ?63.2044 0.2000 4 28 28.49 Infinity 1.6800 29* 28.48 ?64.1888 0.1500 Material 1 1.51450 51.97 30 28.48 ?61.3546 1.0000 SLAH65V 1.80400 46.58 31 28.81 442.1135 16.2110 5 32 35.13 150.2757 8.7000 1.66565 35.63 33 35.56 ?38.4438 1.4000 SFPL55 1.43875 94.66 34 35.44 35.3372 0.8600 35 35.99 35.4743 11.0000 1.66565 35.63 36 35.44 ?55.7379 1.4000 FDS18W 1.94595 17.98 37 35.18 123.2032 46.0663 IMG Aspheric Surface Data Surface 3 r = 1.81355e+02 K = 0.00000e+00 A = ?1.20055e?08 B = ?6.85436e?13 C = 3.59105e?19 D = ?3.89407e?21 E = 0.00000e+00 F = 0.00000e+00 Surface 22 r = 4.39923e+01 K = 0.00000e+00 A = ?5.82385e?08 B = ?3.14565e?10 C = ?6.48513e?13 D = 1.00609e?15 E = 0.00000e+00 F = 0.00000e+00 Surface 29 r = ?6.41888e+01 K = 0.00000e+00 A = ?4.67182e?07 B = ?1.68166e?09 C = 9.63799e?12 D = ?3.54032e?14 E = 4.56322e?17 F = 0.00000e+00 Object at Infinity Distance 2 Distance 3 Focal Length 390.03 375.86 275.02 F-Number 2.91 2.93 3.08 Half Angle of View 3.21 3.32 4.52 Real Image Height 21.84 21.83 21.72 Overall Length 347.00 347.00 347.00 BF 46.20 46.20 46.20 Interval Data d0 Infinity 20000 2000 d12 10.0796 11.8520 28.2638 d14 32.8230 31.0506 14.6391 d27 0.2000 0.6879 5.6778 d31 16.2110 15.7232 10.7332 Unit Data Unit Start Surface Focal Length B1 1 182.4861 B2 13 ?109.0337 B3 15 94.9652 B4 28 ?68.6321 B5 32 181.9574

[0105] Tables 1 to 3 below show various values of each embodiment.

TABLE-US-00007 TABLE 1 Table 1 Wavelength nm Material 1 Material 2 Material 3 Refractive Index 435.8 1.61480 1.60624 1.60194 486.1 1.60321 1.59523 1.59122 546.1 1.59402 1.58648 1.58269 587.6 1.58946 1.58212 1.57844 656.3 1.58396 1.57687 1.57332 Abbe Number vd 30.62 31.72 32.31 Partial Dispersion Ratio ?gF 0.602 0.600 0.599

TABLE-US-00008 TABLE 2 Table 2 Expression Material 1 Material 2 Material 3 Nd + (0.014 ? vd) (1) 2.018 2.026 2.031 Abbe Number vd (2) 30.62 31.72 32.31 ?gF + (0.0024 ? vd) (3) 0.6756 0.6760 0.6763 Hygroscopic (11) 0.170 0.311 0.361 Expansion Ratio ?w Curing Shrinkage (7) 5.90 6.17 6.30 Ratio ? Coefficient of (8) 74 ? 10.sup.?6 82 ? 10.sup.?6 86 ? 10.sup.?6 Linear Expansion ?

TABLE-US-00009 TABLE 3 Table 3 First First Second Second Second Third Third Embodiment Embodiment Embodiment Embodiment Embodiment Embodiment Embodiment Expression PL3, L21 PL1, L41 PL2, L12 PL3, L21 PL1, L31 PL1, L14 PL3, L31 Tmax/Tmin (4) 2.62 1.14 1.04 1.04 1.04 2.10 4.73 Tg/Tp (5) 8.33 8.00 10.00 6.00 6.00 54.32 17.49 |fg/fp| (6) 0.023 0.002 0.005 0.029 0.014 0.036 0.182 Ndg/Nd (9) 1.022 1.115 1.061 1.019 1.019 1.132 1.142 vdg (10) 44.27 49.60 55.35 60.29 60.29 42.24 46.58 Tmax 0.2208 0.1 0.1015 0.1014 0.1014 0.1903 0.3022 Tmin 0.0842 0.0878 0.0974 0.0977 0.0977 0.0908 0.0639 Tp 0.120 0.100 0.100 0.100 0.100 0.150 0.300 Tg 1.000 0.800 1.000 0.600 0.600 8.149 5.248 fp 1663.40 12177.64 ?7146.71 1161.63 1929.77 1476.44 291.81 fg ?38.21 ?27.33 ?34.12 33.17 ?27.44 53.89 53.07 Nd 1.5784 1.5895 1.5821 1.5895 1.5895 1.5935 1.5822 Ndg 1.6134 1.7725 1.6779 1.6204 1.6204 1.8036 1.8077 vdg 44.27 49.60 55.35 60.29 60.29 42.24 46.58

TABLE-US-00010 TABLE 4 Table 4 Fourth Fourth Fourth Fifth Fifth Fifth Fifth Embodiment Embodiment Embodiment Embodiment Embodiment Embodiment Embodiment Expression PL31, L21 PL1, L32 PL32, L61 PL31, L13 PL11, L21 PL32, L51 PL12, L61 Tmax/Tmin (4) 1.75 1.64 1.59 1.33 1.56 1.08 2.24 Tg/Tp (5) 14.00 50.00 5.00 9.33 20.00 12.00 10.00 |fg/fp| (6) 0.034 0.002 0.028 0.016 0.058 0.013 0.018 vdg (9) 46.58 60.47 47.93 67.73 55.53 67.74 49.81 Ndg/Nd (10) 1.143 1.003 1.088 1.011 1.068 1.011 1.018 Tmax 0.1752 0.1637 0.2143 0.1989 0.2054 0.1079 0.224 Tmin 0.1 0.0999 0.1351 0.15 0.1317 0.1 0.1 Tp 0.100 0.100 0.200 0.150 0.150 0.100 0.100 Tg 1.400 5.000 1.000 1.400 3.000 1.200 1.000 fp ?904.26 16524.1 ?1627.7 ?7091.2 1080.4 ?2856.7 ?3863.9 fg ?30.51 35.54 ?46.27 ?112.17 62.24 38.38 ?68.47 Nd 1.5784 1.5895 1.5784 1.5784 1.5895 1.5784 1.5895 Ndg 1.8040 1.5941 1.7170 1.5952 1.6968 1.5952 1.6177 vdg 46.58 60.47 47.93 67.73 55.53 67.74 49.81 Sixth Sixth Sixth Embodiment Embodiment Embodiment Expression PL11, L12 PL12, L33 PL13, L41 Tmax/Tmin (4) 1.89 1.40 1.50 Tg/Tp (5) 45.50 21.67 6.67 |fg/fp| (6) 0.054 0.029 0.025 vdg (9) 81.54 49.60 46.58 Ndg/Nd (10) 0.988 1.170 1.191 Tmax 0.2 0.2106 0.15 Tmin 0.1059 0.15 0.1 Tp 0.200 0.150 0.150 Tg 9.100 3.250 1.000 fp 14058.04 ?3460.52 2653.03 fg 764.70 ?101.73 ?66.95 Nd 1.5145 1.5145 1.5145 Ndg 1.4970 1.7725 1.8040

Imaging Apparatus

[0106] An embodiment of a digital still camera (imaging apparatus) 10 including an optical system according to the present invention as an imaging optical system will be described with reference to FIG. 13. Referring to FIG. 13, an imaging optical system 11 is composed of an optical system according to any one of the first to sixth embodiments. An image pickup device (photoelectric transducer) 12, such as a CCD sensor or a CMOS sensor, is disposed in a camera body 13. The image pickup device 12 receives an optical image formed by the imaging optical system 11 and performs photoelectric conversion on the optical image. The camera body 13 may be a single-lens reflex camera including a quick return mirror or a mirrorless camera including no quick return mirror.

[0107] Thus, when the optical system L0 according to the present invention is applied to an imaging apparatus, such as a digital still camera, a high-resolution image with a wide angle of view can be obtained.

[0108] While the present invention has been described with reference to embodiments, it is to be understood that the invention is not limited to the disclosed embodiments but is determined by the scope of the following claims.

[0109] This application claims the benefit of Japanese Patent Application No. 2022-143624, filed Sep. 9, 2022, which is hereby incorporated by reference herein in its entirety.