JP5750640B2 - Zoom lens and imaging apparatus including the same - Google Patents

Description

  The present invention relates to a zoom lens and an image pickup apparatus including the zoom lens.

  Cameras using an electronic imaging system such as a digital camera are required to be smaller, lighter, and lower in cost. As an optical system of this digital camera, an optical path folding type zoom lens is known. Since the optical path is bent in the optical path folding zoom lens, the thickness of the digital camera can be reduced by using such a zoom lens. As examples of the optical path folding zoom lens, zoom lenses disclosed in Patent Documents 1 to 3 are known.

  The zoom lens of Patent Document 1 has a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a negative refractive power. It is composed of a fourth lens group and a fifth lens group having positive refractive power. Example 1 discloses a zoom lens in which the number of lenses is 10, the half angle of view at the wide-angle end is 31 degrees, and the zoom ratio is slightly less than 3 times.

  The zoom lens of Patent Document 2 has a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a negative refractive power. It is composed of a fourth lens group and a fifth lens group having positive refractive power. Example 1 discloses a zoom lens in which the number of lenses is 10, the half angle of view at the wide-angle end is 40 degrees, and the zoom ratio is slightly higher than 5.

  The zoom lens of Patent Document 3 has a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a negative refractive power. It is composed of a fourth lens group and a fifth lens group having positive refractive power. Example 1 discloses a zoom lens in which the number of lenses is 13, the half angle of view at the wide-angle end is 40 degrees, and the zoom ratio exceeds 6 times.

JP 2005-215165 A JP 2011-095504 A JP 2009-139770 A

  A zoom lens is required to ensure a wide angle of view and a high zoom ratio, but at the same time, it is also required to reduce size, reduce cost, and maintain optical performance.

  However, in the zoom lens disclosed in Patent Document 1, since the distance between the lenses constituting the second lens group (first negative lens group) having negative refractive power is small, the second lens group having negative refractive power. It is difficult to obtain good optical performance with the (first negative lens group). Further, when trying to widen the angle of view, the first lens group (first positive lens group) having positive refractive power tends to be large. Further, since glass lenses having a large specific gravity are frequently used, eccentricity tends to occur when an impact is applied due to an increase in cost or an increase in weight.

  Further, in the zoom lens disclosed in Patent Document 2, since the distance between the lenses constituting the second lens group (first negative lens group) having negative refractive power is small, the second lens group having negative refractive power. It is difficult to obtain good optical performance with the (first negative lens group). In addition, in order to secure a wide angle of view at the wide-angle end, a high-refractive index glass is frequently used for downsizing, which is disadvantageous in terms of cost. In addition, since glass with a large specific gravity is frequently used, it is difficult to reduce the weight, and eccentricity tends to occur when an impact is applied.

  In addition, the zoom lens disclosed in Patent Document 3 has a large number of lenses of 13 and uses a lot of glass material, so that it is not suitable for cost reduction and weight reduction. In particular, in the first lens group having a positive refractive power (first positive lens group) and the second lens group having a negative refractive power (first negative lens group), the lens diameter tends to be large. Since the number of lenses in this lens group is large, it is easily affected by eccentricity when an impact is applied.

  In view of such a problem, the present invention is to maintain optical performance in consideration of the influence of decentering of a lens group having a predetermined negative refractive power while ensuring a high zoom ratio, being small and lightweight, reducing cost. It is a first object to provide an advantageous zoom lens.

  In addition, the present invention provides a zoom lens that is advantageous in maintaining a good optical performance while ensuring a wide angle of view at a wide angle end and a high zoom ratio, and a lens group having a predetermined positive refractive power is small and lightweight. A second object is to provide a lens.

  A third object of the present invention is to provide a zoom lens that is compact and lightweight, has a reduced cost, and is advantageous in maintaining optical performance against temperature changes while ensuring a high zoom ratio.

In order to solve the above-described problem and achieve the first object, a zoom lens according to a first aspect of the invention includes, in order from the object side to the image side, a first positive lens group having a positive refractive power and a first negative refractive power group. 1 negative lens group and a rear lens group having a positive refractive power at the wide angle end ,
The rear lens group includes a second positive lens group having positive refractive power, a second negative lens group disposed on the image side with respect to the second positive lens group, and an image side with respect to the second negative lens group. Having a third positive lens group,
Furthermore, it has an aperture stop disposed between the first negative lens group and the second negative lens group,
When zooming from the wide-angle end to the telephoto end,
The distance from the first positive lens group to the first negative lens group increases;
The distance from the first negative lens group to the second positive lens group decreases,
The distance from the second positive lens group to the second negative lens group changes;
The distance from the second negative lens group to the third positive lens group changes;
The first positive lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first positive lens group is 2,
The first negative lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first negative lens group is 2, and all the lens subgroups in the first negative lens group are single lenses,
The first negative lens group satisfies the following conditional expression (1).
0.20 ≦ D2b / Hw ≦ 0.9 (1)
However,
D2b is a distance on the optical axis from the image side surface of the negative lens subgroup having the negative refractive power in the first negative lens group to the object side surface of the positive lens subgroup having the positive refractive power;
Hw is defined as Hw = fw · tan (ωw),
fw is the focal length of the entire zoom lens system at the wide-angle end,
ωw is a half angle of view with respect to the optical axis when a light beam that passes through the center of the aperture stop at the wide-angle end and enters the maximum image height position of the effective imaging region enters the zoom lens,
It is.

A zoom lens according to a first aspect of the invention includes, in order from the object side to the image side, a first positive lens group having a positive refractive power, a first negative lens group having a negative refractive power, and a rear lens group group having a positive refractive power at the wide angle end ( Hereinafter, in all the description of the invention, it is referred to as “a rear lens group having a positive refractive power” . In the zoom lens according to the first aspect of the invention, the lens configuration of the optical system at the telephoto end is a telephoto type configuration, which is advantageous for shortening the overall length of the zoom lens.

  In the zoom lens according to the first aspect of the invention, the second negative lens group is disposed on the image side of the second positive lens group, and the third positive lens group is further disposed on the image side. With such an arrangement, the absolute values of the refractive power of the second positive lens group and the refractive power of the second negative lens group can be increased, which is advantageous for keeping the exit pupil away from the image plane. In addition, since the zooming action can be shared by the second positive lens group and the second negative lens group, it is advantageous for increasing the zoom ratio and reducing the diameter of the rear lens group.

  In the zoom lens according to the first aspect of the invention, since the aperture stop is disposed between the first negative lens group and the second negative lens group, the aperture stop is located near the center of the zoom lens. Become. For this reason, the positive and negative refractive power arrangements, that is, the arrangement of refractive power across the brightness diaphragm, such as the positive and negative refractive powers on the object side and the negative and positive refractive powers on the image side and the image side, respectively. Become symmetric. This symmetrical arrangement of refractive power can cancel off-axis aberration fluctuations, which is advantageous for correcting off-axis aberrations such as astigmatism and coma during zooming. This leads to a wide angle of view at the wide angle end.

  In addition, by making the movement of each lens group during zooming as described above, the zooming action of the first negative lens group and the second positive lens group can be sufficiently ensured. For this reason, the zoom lens according to the first aspect of the invention is advantageous for both shortening the entire length of the zoom lens and achieving a high zoom ratio.

  By the way, the first positive lens group tends to have a larger lens diameter than the other lens groups. Therefore, in the zoom lens according to the first aspect of the present invention, the first positive lens group is configured as described above so that the entrance pupil is brought closer to the object side in the first positive lens group. Thereby, a 1st positive lens group can be made into a small diameter. Further, since the lens diameter of the first positive lens group can be reduced, the weight of the optical system can be reduced. In addition, the image-side principal point of the first positive lens group can be brought closer to the first negative lens group side, which is advantageous for increasing the focal length at the telephoto end.

  Further, the volume of the first positive lens group and the first negative lens group tends to be larger than the other lens groups. Therefore, in the zoom lens according to the first aspect of the invention, as described above, the refractive power is arranged symmetrically with the brightness stop interposed therebetween. Thereby, the burden of correcting off-axis aberrations in the first positive lens group and the first negative lens group can be reduced. Therefore, even when the total number of lens subgroups in the first positive lens group and the first negative lens group is two, various aberrations including spherical aberration can be corrected satisfactorily. As a result, the volume of the first positive lens group and the first negative lens group can be reduced. In addition, it is advantageous in reducing the size of the zoom lens while having high performance. In particular, configuring the first negative lens group with two single lenses is advantageous in reducing the size of the zoom lens and reducing the cost.

In the zoom lens of the first invention, the first negative lens unit satisfies the following conditional expression (1).
0.20 ≦ D2b / Hw ≦ 0.9 (1)
However,
D2b is the distance on the optical axis from the image side surface of the negative lens subgroup having negative refractive power in the first negative lens group to the object side surface of the positive lens subgroup having positive refractive power;
Hw is defined as Hw = fw · tan (ωw),
fw is the focal length of the entire zoom lens system at the wide-angle end,
ωw is a half angle of view with respect to the optical axis when a light beam that passes through the center of the aperture stop at the wide-angle end and enters the maximum image height position of the effective imaging region enters the zoom lens,
It is.

  Conditional expression (1) specifies the interval on the axis of the two subgroups (two single lenses) constituting the first negative lens group. By securing this axial distance appropriately, even if the two lens subgroups are composed of two single lenses, good optical performance can be ensured over the entire zoom range and the influence of manufacturing errors is reduced. It becomes possible to suppress.

  Here, the refractive power of the positive lens subgroup of the first negative lens group is ensured by appropriately securing the interval between the two subgroups (two single lenses) so as not to fall below the lower limit of the conditional expression (1). It is possible to suppress an excessive increase with respect to the absolute value of the refractive power of the negative lens subgroup. As a result, it is possible to satisfactorily correct the variation in field curvature near the wide-angle end, and to satisfactorily correct spherical aberration and coma near the telephoto end. As a result, even if the optical system has a high zoom ratio, good optical performance can be ensured over the entire zoom range.

  Further, by suppressing the interval between the two subgroups (two single lenses) so as not to exceed the upper limit of the conditional expression (1), the absolute value of the refractive power of the negative lens subgroup of the first negative lens group is It is possible to suppress an excessive increase with respect to the refractive power of the positive lens subgroup. As a result, it is possible to suppress the field curvature near the wide-angle end from becoming a positive tendency, and to suppress the spherical aberration near the telephoto end from being excessive. As a result, good optical performance can be ensured over the entire zoom range.

  In this way, the first negative lens group is set so that the distance between the two sub lens groups (two single lenses) is within the range determined by the upper and lower limit values of the conditional expression (1). Various aberrations generated in the lens group can be reduced. As a result, even if decentration, which is one of the manufacturing errors that have a large effect on optical performance, occurs, in addition to the first negative lens group itself, the performance degradation of the composite system with the front and rear lens groups that are likely to be affected is reduced. Can be reduced. In addition, since the configuration of the first positive lens group and the first negative lens group in which the lens diameter tends to be large can be simplified, the zoom lens can be reduced in size and weight as a whole, and the optical performance when an impact is applied can be reduced. Guarantees are easy.

In order to achieve the second object, a zoom lens according to a second aspect of the invention includes, in order from the object side to the image side, a first positive lens group having a positive refractive power, a first negative lens group having a negative refractive power, and , Has a positive lens power rear lens group,
The rear lens group includes a second positive lens group having positive refractive power, a second negative lens group disposed on the image side with respect to the second positive lens group, and an image side with respect to the second negative lens group. Having a third positive lens group,
And an aperture stop disposed between the first negative lens group and the second positive lens group,
When zooming from the wide-angle end to the telephoto end,
The distance from the first positive lens group to the first negative lens group increases;
The distance from the first negative lens group to the second positive lens group decreases,
The distance from the second positive lens group to the second negative lens group changes;
The distance from the second negative lens group to the third positive lens group changes;
The first positive lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first positive lens group is 2,
The first negative lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first negative lens group is 2, and all the lens subgroups in the first negative lens group are single lenses,
The second positive lens group includes a positive lens subgroup and a second lens subgroup having positive refractive power,
Each of the positive lens subgroup and the second lens subgroup in the second positive lens group is composed of one lens component,
The distance on the optical axis from the aperture stop to the second positive lens group extends at the wide-angle end with respect to the telephoto end,
The first positive lens group satisfies the following conditional expression (2).
3.1 ≦ fP1 / Hw ≦ 5.8 (2)
However,
fP1 is a focal length of the first positive lens group,
Hw is defined as Hw = fw · tan (ωw),
fw is the focal length of the entire zoom lens system at the wide-angle end,
ωw is a half angle of view with respect to the optical axis when a light beam that passes through the center of the aperture stop at the wide-angle end and enters the maximum image height position of the effective imaging region enters the zoom lens,
It is.
Here, the lens component is defined as a lens block in which only two surfaces of the object side surface and the image side surface are in contact with air on the effective surface.

  A zoom lens according to a second aspect of the invention includes, in order from the object side to the image side, a first positive lens group having a positive refractive power, a first negative lens group having a negative refractive power, and a rear lens group group having a positive refractive power. Yes. In the zoom lens according to the second aspect of the invention, the lens configuration of the optical system at the telephoto end is a telephoto type configuration, which is advantageous for shortening the overall length of the zoom lens.

  In the zoom lens according to the second aspect of the invention, the second negative lens group is disposed on the image side of the second positive lens group, and the third positive lens group is further disposed on the image side. With such an arrangement, the absolute values of the refractive power of the second positive lens group and the refractive power of the second negative lens group can be increased, which is advantageous for keeping the exit pupil away from the image plane. In addition, since the zooming action can be shared by the second positive lens group and the second negative lens group, it is advantageous for increasing the zoom ratio and reducing the diameter of the rear lens group.

  In the zoom lens according to the second aspect of the invention, since the aperture stop is disposed between the first negative lens group and the second positive lens group, the aperture stop is located near the center of the zoom lens. Become. For this reason, the positive and negative refractive power arrangements, that is, the arrangement of refractive power across the brightness diaphragm, such as the positive and negative refractive powers on the object side and the negative and positive refractive powers on the image side and the image side, respectively. Become symmetric. This symmetrical arrangement of refractive power can cancel off-axis aberration fluctuations, which is advantageous for correcting off-axis aberrations such as astigmatism and coma during zooming. This leads to a wide angle of view at the wide angle end.

  In addition, by making the movement of each lens group during zooming as described above, the zooming action of the first negative lens group and the second positive lens group can be sufficiently ensured. Therefore, the zoom lens according to the second aspect of the invention is advantageous for both shortening the entire length of the zoom lens and achieving a high zoom ratio.

  By the way, the first positive lens group tends to have a larger lens diameter than the other lens groups. Therefore, in the zoom lens of the second invention, the first positive lens group is configured as described above, so that the entrance pupil is brought closer to the object side in the first positive lens group. Thereby, a 1st positive lens group can be made into a small diameter. Further, since the lens diameter of the first positive lens group can be reduced, the weight of the optical system can be reduced. In addition, the image-side principal point of the first positive lens group can be brought closer to the first negative lens group side, which is advantageous for increasing the focal length at the telephoto end.

  Further, the volume of the first positive lens group and the first negative lens group tends to be larger than the other lens groups. Therefore, in the zoom lens according to the second aspect of the invention, as described above, the refractive power is arranged symmetrically across the brightness stop. Thereby, the burden of correcting off-axis aberrations in the first positive lens group and the first negative lens group can be reduced. Therefore, even when the total number of lens subgroups in the first positive lens group and the first negative lens group is two, various aberrations including spherical aberration can be corrected satisfactorily. As a result, the volume of the first positive lens group and the first negative lens group can be reduced. In addition, it is advantageous in reducing the size of the zoom lens while having high performance.

Note that the first negative lens group, a negative lens subgroup from the object side, by the arrangement in the order of the positive lens subgroup, the refractive power arrangement of a zoom lens system with respect to the aperture stop on the object side of the second positive lens group The symmetry of is further improved. In particular, the first negative lens group is made of two single lenses, which is advantageous for downsizing and cost reduction.

  In the zoom lens according to the second aspect of the invention, the distance from the aperture stop to the second positive lens group is longer at the wide angle end than at the telephoto end. In this way, the refractive power arrangement of the entire zoom lens system with respect to the aperture stop can be made closer to a symmetrical arrangement. In addition, the first negative lens group and the second positive lens group tend to have a large zooming effect, but this makes it easy to cancel out residual aberrations in the first negative lens group and the second positive lens group. . As a result, it is advantageous for correction of aberrations near the wide-angle end, mainly off-axis aberrations such as astigmatism, and aberrations near the telephoto end, mainly off-axis aberrations such as coma.

  In particular, by changing the distance between the aperture stop and the second positive lens group, it is possible to reduce the aberration correction load of the first positive lens group, the first negative lens group, and the second positive lens group. Therefore, even if the optical system has a wide angle of view and a high zoom ratio, deterioration of optical performance can be suppressed. Further, the entrance pupil near the wide-angle end can be easily brought closer to the object side, which is advantageous for further reducing the lens diameter of the first positive lens unit and widening the angle of view of the optical system.

In the zoom lens according to the second aspect of the invention, the first positive lens group satisfies the following conditional expression (2).
3.1 ≦ fP1 / Hw ≦ 5.8 (2)
However,
fP1 is the focal length of the first positive lens group,
Hw is defined as Hw = fw · tan (ωw),
fw is the focal length of the entire zoom lens system at the wide-angle end,
ωw is a half angle of view with respect to the optical axis when a light beam that passes through the center of the aperture stop at the wide-angle end and enters the maximum image height position of the effective imaging region enters the zoom lens,
It is.

  As the overall length of the zoom lens is shortened, the volume of the first positive lens group tends to be the largest. Conditional expression (2) is a condition for keeping the lens diameter of the first positive lens unit small. When the conditional expression (2) is satisfied, the lens diameter of the first positive lens group can be reduced, so that an increase in the volume of the first positive lens group can be suppressed.

  By making the refractive power of the first positive lens unit weak so as not to fall below the lower limit of conditional expression (2), the entrance pupil can be brought closer to the object side. As a result, an increase in the diameter and weight of the first positive lens group having the largest diameter among the lens groups can be suppressed, and astigmatism generated in the first lens group can be favorably corrected.

  Ensuring the refractive power of the first positive lens unit so as not to exceed the upper limit of conditional expression (2) is advantageous for shortening the overall length of the zoom lens.

The zoom lens of the third invention is a reference example, and in order from the object side to the image side, a first positive lens group having a positive refractive power, a first negative lens group having a negative refractive power, and a positive refractive power. Has a rear lens group,
The rear lens group includes a second positive lens group having positive refractive power, a second negative lens group disposed on the image side with respect to the second positive lens group, and an image side with respect to the second negative lens group. Having a third positive lens group,
Furthermore, it has an aperture stop disposed between the first negative lens group and the second negative lens group,
When zooming from the wide-angle end to the telephoto end,
The distance from the first positive lens group to the first negative lens group increases;
The distance from the first negative lens group to the second positive lens group decreases,
The distance from the second positive lens group to the second negative lens group changes;
The distance from the second negative lens group to the third positive lens group changes;
The first positive lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first positive lens group is 2,
The first negative lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first negative lens group is 2,
At least one of the lenses in the first positive lens group and the first negative lens group is a lens having a low first specific gravity that satisfies the following conditional expression (6):
At least one of the lenses in the first positive lens group, the first negative lens group, the second positive lens group, and the second negative lens group has a refractive power of a lens having a small first specific gravity. The lens has a refractive power with a sign different from that of the lens and has a second small specific gravity that satisfies the following conditional expression (6).
0.9 g / cm ³ ≦ SG ≦ 2.0 g / cm ³ (6)
However,
SG is the specific gravity of each of the first low specific gravity lens and the second low specific gravity lens,
It is.

  A zoom lens according to a third aspect of the invention includes, in order from the object side to the image side, a first positive lens group having a positive refractive power, a first negative lens group having a negative refractive power, and a rear lens group group having a positive refractive power. Yes. In the zoom lens according to the third aspect of the invention, the lens configuration of the optical system at the telephoto end is a telephoto type configuration, which is advantageous for shortening the overall length of the zoom lens.

  In the zoom lens according to the third aspect of the invention, the second negative lens group is disposed on the image side of the second positive lens group, and the third positive lens group is further disposed on the image side. With such an arrangement, the absolute values of the refractive power of the second positive lens group and the refractive power of the second negative lens group can be increased, which is advantageous for keeping the exit pupil away from the image plane. In addition, since the zooming action can be shared by the second positive lens group and the second negative lens group, it is advantageous for increasing the zoom ratio and reducing the diameter of the rear lens group.

  In the zoom lens according to the third aspect of the invention, since the aperture stop is disposed between the first negative lens group and the second negative lens group, the aperture stop is located near the center of the zoom lens. Become. For this reason, the positive and negative refractive power arrangements, that is, the arrangement of refractive power across the brightness diaphragm, such as the positive and negative refractive powers on the object side and the negative and positive refractive powers on the image side and the image side, respectively. Become symmetric. This symmetrical arrangement of refractive power can cancel off-axis aberration fluctuations, which is advantageous for correcting off-axis aberrations such as astigmatism and coma during zooming. This leads to a wide angle of view at the wide angle end.

  In addition, by making the movement of each lens group during zooming as described above, the zooming action of the first negative lens group and the second positive lens group can be sufficiently ensured. For this reason, the zoom lens according to the third aspect of the invention is advantageous for both shortening the entire length of the zoom lens and achieving a high zoom ratio.

  By the way, the first positive lens group tends to have a larger lens diameter than the other lens groups. Therefore, in the zoom lens according to the third aspect of the invention, the first positive lens group is configured as described above so that the entrance pupil is brought closer to the object side in the first positive lens group. Thereby, a 1st positive lens group can be made into a small diameter. Further, since the lens diameter of the first positive lens group can be reduced, the weight of the optical system can be reduced. In addition, the image-side principal point of the first positive lens group can be brought closer to the first negative lens group side, which is advantageous for increasing the focal length at the telephoto end.

  Further, the volume of the first positive lens group and the first negative lens group tends to be larger than the other lens groups. Therefore, in the zoom lens according to the third aspect of the invention, as described above, the refractive power is arranged symmetrically with the brightness stop interposed therebetween. Thereby, the burden of correcting off-axis aberrations in the first positive lens group and the first negative lens group can be reduced. Therefore, even when the total number of lens subgroups in the first positive lens group and the first negative lens group is two, various aberrations including spherical aberration can be corrected satisfactorily. As a result, the volume of the first positive lens group and the first negative lens group can be reduced. In addition, it is advantageous in reducing the size of the zoom lens while having high performance.

In the zoom lens according to the third aspect of the invention, at least one of the lenses in the first positive lens group and the first negative lens group has a first low specific gravity that satisfies the following conditional expression (6). What is the refractive power of a lens having at least one lens in the first positive lens group, the first negative lens group, the second positive lens group, and the second negative lens group, the first specific gravity of which is small. This is a lens having a second refractive power with different refractive power and satisfying the following conditional expression (6).
0.9 g / cm ³ ≦ SG ≦ 2.0 g / cm ³ (6)
However,
SG is the specific gravity of each of the first low specific gravity lens and the second low specific gravity lens,
It is.

  As described above, the first positive lens group and the first negative lens group are located closer to the object side than the aperture stop. The first positive lens group and the first negative lens group tend to have a large lens diameter. Therefore, it is preferable that at least one lens in the first positive lens group and the first negative lens group is a lens having a small specific gravity. Thus, by using a material having a small specific gravity as the material of at least one lens, the optical system can be significantly reduced in weight and cost.

  Therefore, in the zoom lens according to the third aspect of the invention, at least one of the lenses in the first positive lens group and the first negative lens group is a lens having a low first specific gravity that satisfies the conditional expression (6). .

  In addition, since the refractive index is low in a material having a small specific gravity, the ability of correcting aberrations is reduced in a lens using such a material. Therefore, in the zoom lens according to the third aspect of the present invention, the specific gravity of the first positive lens group and the first negative lens group is increased by increasing the aberration correction capability of the entire lens group, so that the specific gravity is a conditional expression (1). It was possible to use a lens having an upper limit value of 6) or less.

  If the specific gravity of the lens is too small, it is difficult to increase the refractive index of the lens. For this reason, by making the lens with a small first specific gravity a lens that does not fall below the lower limit of conditional expression (6), it is possible to easily suppress the occurrence of aberrations such as astigmatism and coma that occur on the refractive surface of the lens. ing. Thereby, a lens group can be comprised with few lens subgroups.

  By the way, a lens having a small specific gravity is larger in surface shape change and refractive index change due to temperature change than general glass. Further, in the lenses in the first positive lens group and the first negative lens group, the axial light beam and the off-axis light beam are easily separated and pass, and therefore, the change in the surface shape and refractive index of the lens having a small specific gravity is the main. It affects the curvature of field.

Therefore, when at least one lens in the first positive lens group and the first negative lens group satisfies the conditional expression (6), a change in field curvature occurs due to a temperature change.

  Therefore, any lens in the first positive lens group to the second negative lens group that is likely to change in field curvature due to a temperature change has a sign opposite to the sign of the refractive power of the lens having a small specific gravity. By using a lens having a refractive power and having a small specific gravity that satisfies the conditional expression (6), it is possible to cancel the change in field curvature due to a temperature change and to secure optical performance. The specific gravity is based on the definition of JIS standard.

In order to achieve the second object, a zoom lens according to a fourth aspect of the invention includes, in order from the object side to the image side, a first positive lens group having a positive refractive power, a first negative lens group having a negative refractive power, , Has a positive lens power rear lens group,
The rear lens group includes a second positive lens group having positive refractive power, a second negative lens group disposed on the image side with respect to the second positive lens group, and an image side with respect to the second negative lens group. Having a third positive lens group,
The first negative lens group and the second positive lens group are arranged without any other lens group in between,
And an aperture stop disposed between the first negative lens group and the second positive lens group,
When zooming from the wide-angle end to the telephoto end,
The distance from the first positive lens group to the first negative lens group increases;
The distance from the first negative lens group to the second positive lens group decreases,
The distance from the second positive lens group to the second negative lens group changes;
The distance from the second negative lens group to the third positive lens group changes;
The first positive lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first positive lens group is 2,
The first negative lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first negative lens group is 2, and all the lens subgroups in the first negative lens group are single lenses,
The second positive lens group includes a positive lens subgroup and a second lens subgroup having positive refractive power,
Each of the positive lens subgroup and the second lens subgroup in the second positive lens group is composed of one lens component,
A distance on the optical axis from the aperture stop to the second positive lens group is widened at a wide angle end with respect to a telephoto end.
Here, the lens component is defined as a lens block in which only two surfaces of the object side surface and the image side surface are in contact with air on the effective surface.

  A zoom lens according to a fourth aspect of the invention includes, in order from the object side to the image side, a first positive lens group having a positive refractive power, a first negative lens group having a negative refractive power, and a rear lens group group having a positive refractive power. Yes. In the zoom lens according to the fourth aspect of the invention, the lens configuration of the optical system at the telephoto end is a telephoto type configuration, which is advantageous for shortening the overall length of the zoom lens.

  In the zoom lens according to the fourth aspect of the invention, the second negative lens group is disposed on the image side of the second positive lens group, and the third positive lens group is further disposed on the image side. With such an arrangement, the absolute values of the refractive power of the second positive lens group and the refractive power of the second negative lens group can be increased, which is advantageous for keeping the exit pupil away from the image plane. In addition, since the zooming action can be shared by the second positive lens group and the second negative lens group, it is advantageous for increasing the zoom ratio and reducing the diameter of the rear lens group.

  In the zoom lens according to the fourth aspect of the invention, the first negative lens group and the second positive lens group are arranged without any other lens group in between. That is, the second positive lens group is disposed immediately after the image side of the first negative lens group. For this reason, residual aberrations occurring in each of the first negative lens group and the second positive lens group having a large zooming function can be easily canceled out. As a result, while simplifying the configuration of the first negative lens group, it is possible to ensure performance in the entire zoom range, reduce optical performance deterioration due to decentration, and make it easier to guarantee optical performance.

In the zoom lens according to the fourth aspect of the invention, since the aperture stop is disposed between the first negative lens unit and the second positive lens unit, the aperture stop is located near the center of the zoom lens. Become. For this reason, the positive and negative refractive power arrangements, that is, the arrangement of refractive power across the brightness diaphragm, such as the positive and negative refractive powers on the object side and the negative and positive refractive powers on the image side and the image side, respectively. Become symmetrical. This symmetrical arrangement of refractive power can cancel off-axis aberration fluctuations, which is advantageous for correcting off-axis aberrations such as astigmatism and coma during zooming. This leads to a wide angle of view at the wide angle end.
In addition, the first positive lens unit can be downsized and a wide angle of view at the wide angle end can be obtained.

  In addition, by making the movement of each lens group during zooming as described above, the zooming action of the first negative lens group and the second positive lens group can be sufficiently ensured. Therefore, the zoom lens according to the fourth aspect of the invention is advantageous for both shortening the entire length of the zoom lens and achieving a high zoom ratio.

  By the way, the first positive lens group tends to have a larger lens diameter than the other lens groups. Therefore, in the zoom lens according to the fourth aspect of the present invention, the first positive lens group is configured as described above so that the entrance pupil is brought closer to the object side in the first positive lens group. Thereby, a 1st positive lens group can be made into a small diameter. Further, since the lens diameter of the first positive lens group can be reduced, the weight of the optical system can be reduced. In addition, the image-side principal point of the first positive lens group can be brought closer to the first negative lens group side, which is advantageous for increasing the focal length at the telephoto end.

  Further, the volume of the first positive lens group and the first negative lens group tends to be larger than the other lens groups. Therefore, in the zoom lens according to the fourth aspect of the present invention, as described above, the refractive power is arranged symmetrically across the brightness stop. Thereby, the burden of correcting off-axis aberrations in the first positive lens group and the first negative lens group can be reduced. Therefore, even when the total number of lens subgroups in the first positive lens group and the first negative lens group is two, various aberrations including spherical aberration can be corrected satisfactorily. As a result, the volume of the first positive lens group and the first negative lens group can be reduced. In addition, it is advantageous in reducing the size of the zoom lens while having high performance.

Note that the first negative lens group, a negative lens subgroup from the object side, by the arrangement in the order of the positive lens subgroup, the refractive power arrangement of a zoom lens system with respect to the aperture stop on the object side of the second positive lens group The symmetry of is further improved. In particular, the first negative lens group is made of two single lenses, which is advantageous for downsizing and cost reduction.

  In the zoom lens according to the fourth aspect of the invention, the distance from the aperture stop to the second positive lens group is longer at the wide angle end than at the telephoto end. In this way, the refractive power arrangement of the entire zoom lens system with respect to the aperture stop can be made closer to a symmetrical arrangement. In addition, the first negative lens group and the second positive lens group tend to have a large zooming effect, but this makes it easy to cancel out residual aberrations in the first negative lens group and the second positive lens group. . As a result, it is advantageous for correction of aberrations near the wide-angle end, mainly off-axis aberrations such as astigmatism, and aberrations near the telephoto end, mainly off-axis aberrations such as coma.

In particular, by changing the distance between the aperture stop and the second positive lens group, it is possible to reduce the aberration correction load of the first positive lens group, the first negative lens group, and the second positive lens group. Therefore, even if the optical system has a wide angle of view and a high zoom ratio, deterioration of optical performance can be suppressed. Further, the entrance pupil near the wide-angle end can be easily brought closer to the object side, which is advantageous for further reducing the lens diameter of the first positive lens unit and widening the angle of view of the optical system.
Also, by arranging the second positive lens group immediately after the image side of the first negative lens group, residual aberrations occurring in each of the first negative lens group and the second positive lens group having a large zooming effect are mutually reduced. Can be easily offset. For this reason, while simplifying the configuration of the first negative lens group, it is possible to secure performance in the entire zoom range and reduce performance deterioration due to decentration, thereby facilitating performance guarantee.

  It is more preferable that the above-described configurations satisfy each other at the same time.

  Further, when the zoom lens of the first to fourth inventions has a focusing function, it is configured in the farthest focusing state.

  More preferably, the zoom lens of the first to fourth inventions (hereinafter referred to as the zoom lens of the present invention) simultaneously satisfies any one of the following configurations, and further a plurality of configurations.

  In the zoom lens of the present invention, it is preferable that the first positive lens group includes a reflecting member, and the reflecting member is disposed between the negative lens sub group and the positive lens sub group of the first positive lens group.

  In the zoom lens of the present invention, the distance between the negative lens subgroup and the positive lens subgroup of the first positive lens group can be widened. Therefore, by disposing a reflecting member between the negative lens subgroup and the positive lens subgroup, it is possible to reflect light (bend the optical path) by the reflecting member. In other words, an optical system layout that is advantageous for making the imaging device thinner can be achieved. Note that the optical path is particularly preferably bent at an angle of 90 degrees.

  In the zoom lens of the present invention, it is preferable that the first lens group is fixed with respect to the imaging position during zooming.

  In this way, since the entire length of the zoom lens can be fixed, it is not necessary to move the first positive lens group having the largest lens diameter. In addition, it is easy to reduce power consumption and drive noise.

  In the zoom lenses according to the first to third aspects of the invention, it is preferable that the first negative lens group and the second positive lens group are arranged without any other lens group in between.

  In this way, the second positive lens group is arranged immediately after the image side of the first negative lens group. For this reason, residual aberrations occurring in each of the first negative lens group and the second positive lens group having a large zooming function can be easily canceled out. As a result, while simplifying the configuration of the first negative lens unit, it is possible to ensure high optical performance in the entire zoom range, reduce optical performance degradation due to decentration, and make it easier to guarantee optical performance. .

In the zoom lenses according to the first and third aspects of the present invention, it is preferable that the aperture stop be disposed between the first negative lens group and the second positive lens group.
By doing so, the arrangement of the refractive power of the entire zoom lens system with respect to the aperture stop becomes a more symmetrical arrangement. Further, since the first negative lens group and the second positive lens group tend to have a large zooming effect, the residual aberration tends to increase. However, the residual aberrations of the first negative lens group and the second positive lens group can be offset better. Can be made. Therefore, it is advantageous for correcting off-axis aberrations such as astigmatism mainly near the wide-angle end, and off-axis aberrations mainly coma aberration near the telephoto end. Further, it is advantageous for reducing the size of the first positive lens unit and increasing the angle of view at the wide angle end.

  In the zoom lenses according to the first and third aspects of the invention, it is preferable that the distance on the optical axis from the aperture stop to the second positive lens group is wider at the wide angle end than at the telephoto end.

  By changing the distance between the aperture stop and the second positive lens group, it is possible to reduce the load of aberration correction in the first positive lens group, the first negative lens group, and the second positive lens group. Therefore, even if the optical system has a wide angle of view and a high zoom ratio, deterioration of optical performance can be suppressed. Further, the entrance pupil near the wide-angle end can be easily brought closer to the object side, which is advantageous for further reducing the lens diameter of the first positive lens unit and widening the angle of view of the optical system.

  In the zoom lens of the present invention, it is preferable that the aperture stop is fixed with respect to the imaging position during zooming.

  By fixing the position of the aperture stop with respect to the imaging position in the entire zoom range, it becomes possible to simplify the drive device and to maintain the aperture stop stably. Therefore, it is advantageous for cost reduction and stabilization of optical performance when an impact is applied.

In the zoom lens of the present invention, it is preferable that both the negative lens subgroup and the positive lens subgroup in the first positive lens group are composed of one lens component.
In the zoom lens of the present invention, it is preferable that the negative lens subgroup and the positive lens subgroup in the first positive lens group are single lenses.

  By doing so, it is advantageous for further miniaturization and weight reduction of the optical system.

In the zoom lens of the reference example , it is preferable that both the negative lens sub group and the positive lens sub group in the first negative lens group are composed of one lens component.
In the zoom lens according to the present invention, as described above, the negative lens subgroup and the positive lens subgroup in the first negative lens group are preferably single lenses.

  By doing so, it is advantageous for further miniaturization and weight reduction of the optical system.

  In the zoom lens according to the present invention, the second positive lens group includes a positive lens subgroup having positive refractive power and a second lens subgroup disposed closer to the image side than the positive lens subgroup having positive refractive power. The second lens sub-group has an absolute value of refractive power smaller than the absolute value of the refractive power of the positive lens sub-group in the second positive lens group, and the second lens sub-group of the lens sub-group in the second positive lens group The total number is preferably 2.

  By configuring the second positive lens group in the order of the positive lens sub group and the second lens sub group having a refractive power lower than that of the positive lens sub group, the main point of the second positive lens group is the first negative lens group. Can be located on the side. Accordingly, when the distance between the first negative lens group and the second positive lens group is changed, it is advantageous to sufficiently ensure a zooming action due to the change in the distance.

  In the zoom lens of the present invention, it is preferable that the second lens subgroup in the second positive lens group is a negative lens subgroup having a negative refractive power.

  By doing so, it is more advantageous to position the principal point of the second positive lens group on the first negative lens group side.

  In the zoom lens of the present invention, it is preferable that each of the positive lens sub group and the second lens sub group in the second positive lens group is one lens component. Here, the lens component is defined as a lens block in which only two surfaces of the object side surface and the image side surface are in contact with air on the effective surface.

  By doing so, the optical system can be further reduced in size and weight. In addition, since the second positive lens group is a lens group in which the zooming action tends to be large, if a manufacturing error occurs, the influence on spherical aberration on the telephoto side and astigmatism on the wide-angle side tends to be large. . Therefore, by configuring the second positive lens group with two lens components, it is possible to reduce the influence of aberration due to decentration. Here, the lens component is a lens block in which only two surfaces of the object side surface and the image side surface are in contact with air in the effective optical path through which the light beam passes. It is.

In the zoom lenses of the first, second, and fourth inventions, at least one of the lenses in the first positive lens group and the first negative lens group satisfies the following conditional expression (6). 1 is a lens having a small specific gravity, and at least one of the lenses in the first positive lens group, the first negative lens group, the second positive lens group, and the second negative lens group has a low first specific gravity. It is preferable that the lens has a refractive power with a sign different from that of the lens and has a small second specific gravity that satisfies the following conditional expression (6).
0.9 g / cm ³ ≦ SG ≦ 2.0 g / cm ³ (6)
However,
SG is the specific gravity of each of the first low specific gravity lens and the second low specific gravity lens,
It is.

  The function and effect are as described in the zoom lens of the third invention.

In the zoom lens of the present invention, it is preferable that the first low specific gravity lens and the second low specific gravity lens satisfy the following conditional expression (7).
1.45 ≦ ndPL ≦ 1.8 (7)
However,
ndPL is the refractive index with respect to the d-line of the first low specific gravity lens and the second low specific gravity lens,
It is.

  By setting the refractive indexes of the lens having a low first specific gravity and the lens having a low second specific gravity within the range of the conditional expression (7), the Petzval sum can be easily maintained. Therefore, the shape of the image surface is good without using a high refractive index lens (for example, a lens with a d-line refractive index exceeding 1.9) in the first positive lens group or the first negative lens group. It is possible to keep on.

  In addition, the lens material generally tends to have a higher specific gravity as the refractive index is higher. Here, the first positive lens group and the first negative lens group tend to have a large lens diameter. Therefore, using a lens that satisfies the conditional expression (7) is advantageous in reducing the weight of the first positive lens group and the first negative lens group.

  In the zoom lens according to the aspect of the invention, it is preferable that the second low specific gravity lens is included in either the first positive lens group or the first negative lens group.

  The second low specific gravity lens is preferably a lens in the first positive lens group or the first negative lens group. The first positive lens group and the first negative lens group are located at a distance close to each other near the wide-angle end. For this reason, even if the astigmatism of the first low specific gravity lens and the second low specific gravity lens change due to temperature change, they cancel each other, so that deterioration of optical performance due to temperature change can be prevented. Moreover, it is advantageous for further weight reduction of the optical system.

  In the zoom lens of the present invention, it is preferable that the second negative lens unit moves to the image side during focusing from a long distance object to a short distance object.

  When a material having a large shape change due to temperature, such as plastic, is used for the lens, or when the focal length at the telephoto end is made longer, the change in the focus position due to the temperature change becomes larger. This change in the focus position can be corrected by adjusting the position of the focus lens group. In this case, if the change in focus position (image plane position) is too small with respect to the movement amount of the focus lens group, the movement amount of the focus lens group must be increased. Then, the focal length and the field curvature are likely to change. On the other hand, if the focal position (image plane position) changes too much with respect to the amount of movement of the focus lens group, it becomes difficult to control the position of the focus lens group.

  Therefore, in the zoom lens of the present invention, the first positive lens group and the first negative lens group are arranged in this order from the object side, and further, the second positive lens group, the second negative lens group, By disposing the third positive lens group, the exit pupil can be moved away from the image side while increasing the refractive power of the second positive lens group and the second negative lens group. In addition, since the zooming action can be shared by the second positive lens group and the second negative lens group, it is easy to set the focus sensitivity of the second negative lens group. Therefore, smooth focusing can be performed by moving the second negative lens unit.

In the zoom lens according to the present invention, it is preferable that the second negative lens group satisfies the following conditional expression (3).
2.0 ≦ | fN2 / Ht | ≦ 4.5 (3)
However,
fN2 is the focal length of the second negative lens group,
Ht is defined by Ht = ft · tan (ωt),
ft is the focal length of the entire zoom lens system at the telephoto end,
ωt is a half angle of view with respect to the optical axis when a light beam that passes through the center of the aperture stop at the telephoto end and enters the maximum image height position of the effective imaging region enters the zoom lens,
It is.

  By increasing the refractive power of the second positive lens group and the second negative lens group, it is possible to enhance the zooming action. Conditional expression (3) is a conditional expression for making it easy to obtain good optical performance over the entire zooming range even if this zooming effect is enhanced.

  By making sure that the lower limit of conditional expression (3) is not exceeded, it is possible to suppress an excessive zooming effect in the second negative lens unit. As a result, it is advantageous for suppressing variations in spherical aberration and astigmatism. Further, by suppressing an excessive zooming effect in the second negative lens group, it becomes easy to correct aberrations such as spherical aberration and astigmatism with a small number of lenses. In addition, since the second negative lens group can be composed of a single lens, the weight of the optical system can be reduced.

  By making sure that the upper limit of conditional expression (3) is not exceeded, it becomes easy to secure the zooming action in the second negative lens group, and therefore a desired zooming ratio can be secured. In addition, since it is relatively easy to suppress an excessive zooming effect in the second positive lens group, it is possible to reduce aberrations such as spherical aberration and astigmatism in the second positive lens group.

In the zoom lens according to the present invention, it is preferable that the second negative lens group satisfies the following conditional expression (4).
0.3 ≦ | fN2 / ft | ≦ 0.7 (4)
However,
fN2 is the focal length of the second negative lens group,
ft is the focal length of the entire zoom lens system at the telephoto end,
It is.

  By increasing the refractive power of the second positive lens group and the second negative lens group, it is possible to enhance the zooming action. Conditional expression (4) is a conditional expression for making it easy to obtain good optical performance over the entire zooming range even if this zooming effect is enhanced.

  By making sure that the lower limit of conditional expression (4) is not exceeded, it is possible to suppress an excessive zooming effect in the second negative lens unit. As a result, it is advantageous for suppressing variations in spherical aberration and astigmatism near the telephoto end. Further, by suppressing an excessive zooming effect in the second negative lens group, it becomes easy to correct aberrations such as spherical aberration and astigmatism with a small number of lenses. In addition, since the second negative lens group can be composed of a single lens, the weight of the optical system can be reduced.

  By making so as not to exceed the upper limit of conditional expression (4), it becomes easy to ensure the zooming effect in the second negative lens group, and therefore a desired zooming ratio can be ensured. In addition, since it is relatively easy to suppress an excessive zooming effect in the second positive lens group, it is possible to reduce aberrations such as spherical aberration and astigmatism in the second positive lens group.

In the zoom lenses according to the second to fourth aspects of the invention, it is preferable that the first negative lens group satisfies the following conditional expression (1).
0.20 ≦ D2b / Hw ≦ 0.9 (1)
However,
D2b is the distance on the optical axis from the image side surface of the negative lens subgroup having negative refractive power in the first negative lens group to the object side surface of the positive lens subgroup having positive refractive power;
Hw is defined as Hw = fw · tan (ωw),
fw is the focal length of the entire zoom lens system at the wide-angle end,
ωw is a half angle of view with respect to the optical axis when a light beam that passes through the center of the aperture stop at the wide-angle end and enters the maximum image height position of the effective imaging region enters the zoom lens,
It is.

  The function and effect are as described in the zoom lens of the first invention.

  In the zoom lens according to the third aspect of the present invention, it is preferable that all the lens subgroups in the first negative lens group are single lenses.

  Since the first positive lens group and the first negative lens group have large lens diameters, it is preferable to simplify the configuration of these lens groups. Therefore, by making all the lens subgroups in the first negative lens group a single lens, it is possible to reduce the overall weight of the optical system, and it is advantageous for guaranteeing optical performance when an impact is applied.

In the zoom lens of the present invention, it is preferable that the first positive lens group satisfies the following conditional expression (5).
0.2 ≦ D1b / fP1 ≦ 0.6 (5)
However,
D1b is the air equivalent distance along the optical axis from the image side surface of the negative lens subgroup having negative refractive power in the first positive lens group to the object side surface of the positive lens subgroup having positive refractive power;
fP1 is the focal length of the first positive lens group,
It is.

  The first positive lens group is a lens group that tends to have a large lens diameter among the zoom lenses. Conditional expression (5) is a conditional expression that is advantageous for both reducing the size of the entire zoom lens by reducing the diameter of the first positive lens unit and ensuring the optical performance.

  By making sure that the lower limit of conditional expression (5) is not exceeded, the entrance pupil in the first positive lens group can be brought closer to the object side, so that the incident light height in the first positive lens group can be kept low. . Thereby, the diameter and weight of the first positive lens group can be reduced. In addition, since the configuration in which the reflecting member is inserted between the lens subgroups of the first positive lens group is facilitated, a zoom lens of a type that bends the optical path can be easily realized.

  By preventing the upper limit of conditional expression (5) from being exceeded, the overall length of the zoom lens can be shortened. In addition, it is easy to suppress the occurrence of astigmatism that occurs between the two lens subgroups of the first lens group. Furthermore, each lens subgroup in the first positive lens group can be constituted by one single lens.

  In the zoom lens of the present invention, it is preferable that all the lens subgroups in the first positive lens group are single lenses.

  This is advantageous for reducing the cost of the optical system.

  In the zoom lens of the present invention, it is preferable that the most object side lens surface of the negative lens subgroup in the first positive lens group is a concave lens surface on the object side.

  By making the lens surface closest to the object side of the first positive lens group a concave lens surface on the object side, it becomes easy to secure the distance between the negative lens sub group and the positive lens sub group in the first positive lens group. Therefore, it is advantageous to secure a space for arranging the reflecting member in the first positive lens group. Moreover, since the incident height of the light beam to the first positive lens group can be lowered, the lens diameter can be reduced.

In the zoom lens according to the present invention, it is preferable that the first negative lens unit satisfies the following conditional expression (8).
0.45 ≦ | fN1n | × fN1p / fN1 ² ≦ 1.8 (8)
However,
fN1n is the focal length of the negative lens subgroup in the first negative lens group,
fN1p is the focal length of the positive lens subgroup in the first negative lens group,
fN1 is the focal length of the first negative lens group
It is.

  Necessary to ensure optical performance in both lens subgroups by preventing the refractive power of both lens subgroups in the first negative lens group from becoming excessively high so as not to fall below the lower limit of conditional expression (8). This is advantageous in ensuring a sufficient distance between the two lens subgroups.

  By increasing both the refractive powers of both lens subgroups in the first negative lens group so as not to exceed the upper limit of conditional expression (8), the size of the first negative lens group can be easily suppressed, and both lens subgroups can be controlled. This is advantageous in ensuring the function of canceling out aberrations between groups.

  Ωw in conditional expressions (1) and (2) will be described with reference to FIG. FIG. 22 shows a state in which the zoom lens, the aperture stop, and the imaging surface are arranged on the optical axis. The light beam incident on the zoom lens passes through the aperture stop, and then exits from the zoom lens and reaches the imaging surface.

  In FIG. 22, L indicated by a solid line indicates a light ray that reaches the point X on the effective imaging region among light rays that pass through the center of the aperture stop. This point X is the position farthest from the optical axis in the effective imaging region. Here, since the effective imaging region is a region where an object image is formed, the point X is at the maximum image height position. Thus, the light ray L is a light ray that passes through the center of the aperture stop and enters the maximum image height position of the effective imaging region. Ωw is a half angle of view with respect to the optical axis of the light beam L at the wide angle end. On the other hand, ωt in the conditional expression (3) is a half field angle with respect to the optical axis of the light beam L at the telephoto end.

  The configuration of the zoom lens according to the present invention is suitable for a configuration in which the exit pupil is separated from the image plane. For this reason, it is preferable to use for the electronic imaging device provided with the electronic imaging element. Here, the electronic image sensor is an element that converts an image formed by the zoom lens into an electric signal.

  Therefore, an image pickup apparatus according to the present invention includes the zoom lens described above and an image pickup element disposed on the image side of the zoom lens. As a result, it is possible to realize an imaging apparatus in which various aberrations are favorably corrected while having a wide zoom ratio and a high zoom ratio. In particular, when the zoom lens has a reflecting member, a thin imaging device can be realized.

  The above-described configurations can be more effectively combined with each other arbitrarily. Furthermore, by limiting the lower limit value and the upper limit value of each conditional expression as follows, it becomes more advantageous to exhibit its function.

For conditional expression (1),
The lower limit value is more preferably 0.24, and even more preferably 0.25.
The upper limit value is more preferably 0.75, and even more preferably 0.72.

For conditional expression (2),
More preferably, the lower limit value is 3.3.
More preferably, the upper limit value is 5.0, more preferably 4.6.

Conditional expression (3)
It is more preferable to set the lower limit value to 2.2, and further to 2.4.
More preferably, the upper limit value is 4.0, more preferably 3.7.

For conditional expression (4),
More preferably, the lower limit value is 0.34, more preferably 0.345.
More preferably, the upper limit value is 0.57, more preferably 0.56.

For conditional expression (5),
The lower limit value is more preferably 0.3, and further preferably 0.35.
More preferably, the upper limit value is 0.55, more preferably 0.52.

For conditional expression (6),
More preferably, the lower limit is set to 0.9.
More preferably, the upper limit value is 1.6.

For conditional expression (7),
More preferably, the lower limit is 1.49.
More preferably, the upper limit value is 1.76.

Conditional expression (8)
The lower limit value is more preferably 0.5, and further preferably 0.55.
More preferably, the upper limit value is 1.7, and more preferably 1.6.

  According to the present invention, there is provided a zoom lens that is advantageous in maintaining optical performance in consideration of the influence of decentering of a lens group having a predetermined negative refractive power, with a small size and light weight, while ensuring a high zoom ratio. Can be provided.

  In addition, while ensuring a wide angle of view and a high zoom ratio at the wide-angle end, a lens group having a predetermined positive refractive power is small and light, a cost is reduced, and a zoom lens that is advantageous for maintaining good optical performance is provided. be able to.

  In addition, it is possible to provide a zoom lens that is small and lightweight, has a reduced cost, and is advantageous in maintaining optical performance due to a temperature change while ensuring a high zoom ratio.

  In addition, it is possible to realize an imaging apparatus in which various aberrations are favorably corrected while having a wide zoom ratio and a high zoom ratio.

FIGS. 5A to 5C are lens cross-sectional views at the wide-angle end, the intermediate focal length state, and the telephoto end during focusing on an object point at infinity according to the first embodiment of the zoom lens of the present invention, respectively. FIGS. FIGS. 7A to 7C are lens cross-sectional views at the wide-angle end, the intermediate focal length state, and the telephoto end when the zoom lens of the second embodiment of the present invention is focused on an object point at infinity. FIGS. 7A to 7C are lens cross-sectional views at the wide-angle end, the intermediate focal length state, and the telephoto end when the zoom lens of the third embodiment of the present invention is focused on an object point at infinity, respectively. FIGS. (A)-(c) is a lens sectional view at the wide-angle end, intermediate focal length state, and telephoto end at the time of focusing on an object point at infinity in the fourth embodiment of the zoom lens of the present invention, respectively. (A)-(c) is a lens sectional view at the wide-angle end, intermediate focal length state, and telephoto end at the time of focusing on an object point at infinity in the fifth embodiment of the zoom lens of the present invention, respectively. (A)-(c) is a lens sectional view at the wide-angle end, intermediate focal length state, and telephoto end at the time of focusing on an object point at infinity in the sixth embodiment of the zoom lens of the present invention, respectively. FIGS. 7A to 7C are lens cross-sectional views at the wide-angle end, the intermediate focal length state, and the telephoto end during focusing on an object point at infinity according to the seventh embodiment of the zoom lens of the present invention, respectively. FIGS. (A)-(c) is a lens sectional drawing in the wide-angle end, intermediate | middle focal-distance state at the time of an infinite object point focusing of the 8th Example of the zoom lens of this invention, respectively, and a telephoto end. (A)-(l) is an aberrational diagram at the time of focusing on an object point at infinity according to the first embodiment. (A)-(l) is an aberrational figure at the time of focusing on an object point at infinity of 2nd Example, respectively. (A)-(l) is an aberrational diagram at the time of focusing on an object point at infinity according to the third embodiment. (A)-(l) is an aberrational diagram at the time of focusing on an object point at infinity according to the fourth embodiment. (A)-(l) is an aberrational figure at the time of an infinite object point focusing of 5th Example, respectively. (A)-(l) is an aberrational diagram at the time of focusing on an object point at infinity according to the sixth example. (A)-(l) is an aberrational diagram at the time of focusing on an object point at infinity according to the seventh example. (A)-(l) is an aberrational diagram at the time of focusing on an object point at infinity according to the eighth example. It is a figure explaining correction | amendment of a distortion aberration. It is a front perspective view which shows the external appearance of the digital camera incorporating the optical path bending zoom lens by this invention. It is a rear perspective view of the digital camera. It is a conceptual diagram of the internal structure of the said digital camera. It is a block diagram of the internal circuit of the main part of the digital camera. It is a figure for demonstrating (omega) w.

  Embodiments of a zoom lens and an imaging apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Examples 1 to 8 of the zoom lens according to the present invention will be described below. FIGS. 1 to 8 show lens cross sections at the wide-angle end (a), the intermediate focal length state (b), and the telephoto end (c) when focusing on an object point at infinity in Examples 1 to 8. FIG. 1 to 8, the first lens group is G1, the second lens group is G2, the third lens group is G3, the fourth lens group is G4, the fifth lens group is G5, the sixth lens group is G6, and the brightness. The aperture is indicated by S, the infrared light cut filter is indicated by F, the cover glass is indicated by C, and the image plane is indicated by I.
Each zoom lens shown in the embodiment is a zoom lens mainly using an electronic image sensor, has a zoom ratio of 4 times or more from a wide angle region (preferably a half angle of view of 32 degrees or more), is small, and has a manufacturing error. The imaging optical system has a configuration that can be easily guaranteed, is lightweight, can be manufactured at low cost, and can be more easily guaranteed in impact performance.
Further, in order to electrically correct the negative distortion at the wide angle end, the image height at the wide angle end is smaller than the image height at the telephoto end.

  Here, the infrared light cut filter F may be a low-pass filter provided with a coat (multilayer film) for cutting infrared light. The cover glass C is a parallel plate of the electronic image sensor. In addition, you may give the coat which cuts infrared light on the surface of the cover glass C. FIG. Further, the cover glass C may have a low-pass filter action.

  The numerical data is data in a state in which the object (object) at infinity is in focus. The unit of length of each numerical value is mm, and the angle is ° (degrees). Further, the zoom data are values at the wide-angle end, the intermediate focal length state, and the telephoto end.

1 to 8, the illustration of the reflecting surface in the prism (reflecting member) is omitted, and the prism is shown in two planes as a developed view, but in reality, it is indicated by P in FIG. The prism is a right angle prism.
Regarding focusing from a long distance to a short distance, in the first to sixth and eighth embodiments, the fourth lens group G4 moves to the image side, and in the seventh embodiment, the fifth lens group G5 moves to the image side.

  As shown in FIG. 1, the zoom lens of Example 1 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, and positive refraction. It has a third lens group G3 having a strong power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. In FIG. 1, r21, r22, and r23 are virtual planes.

  The first lens group G1 having positive refractive power is the first positive lens group, the second lens group G2 having negative refractive power is the first negative lens group, the third lens group G3 having positive refractive power is the second positive lens group, and negative refraction. The fourth lens group G4 for power is a second negative lens group, and the fifth lens group G5 for positive refractive power is a third positive lens group.

  During zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves to the image side, the third lens group G3 moves to the object side, and the fourth lens group G4. Moves to the object side, and the fifth lens group G5 is fixed. The aperture stop S is fixed, and the light amount is adjusted by changing the aperture size.

  In order from the object side, the first lens group G1 includes a biconcave negative lens L1, an optical path bending prism L2, and a biconvex positive lens L3. The second lens group G2 includes a biconcave negative lens L4 and a positive meniscus lens L5 having a convex surface directed toward the object side. The third lens group G3 includes a biconvex positive lens L6, and a cemented lens of a biconcave negative lens L7 and a biconvex positive lens L8. The fourth lens group G4 includes a negative meniscus lens L9 having a concave surface directed toward the object side. The fifth lens group G5 is composed of a biconvex positive lens L10.

  The aspherical surfaces are positive surfaces with the convex surfaces facing both surfaces of the biconcave negative lens L1 of the first lens group G1, both surfaces of the biconvex positive lens L3, both surfaces of the biconcave negative lens L4 of the second lens group G2, and the object side. Both surfaces of the meniscus lens L5, both surfaces of the biconvex positive lens L6 of the third lens group G3, both surfaces of the negative meniscus lens L9 with the concave surface facing the object side of the fourth lens group G4, and the biconvex positive lens of the fifth lens group G5 It is used for a total of 14 sides, both sides of L10.

  In FIG. 1, the object side surface and the image side surface of the prism L2 are both flat, and there is a reflecting surface (not shown) between them. The rear lens group is a third lens group G3, a fourth lens group G4, and a fifth lens group G5.

  The first lens group G1 is composed of two lens subgroups. The biconcave negative lens L1 is a negative lens subgroup having negative refractive power, and the biconvex positive lens L3 is a positive lens subgroup having positive refractive power.

  The second lens group G2 includes two lens subgroups, the biconcave negative lens L4 is a negative lens subgroup having negative refractive power, and the positive meniscus lens L5 having a convex surface facing the object side is a positive lens having positive refractive power. It is a subgroup.

  The distance on the optical axis from the aperture stop S to the third lens group G3 is wider at the wide-angle end than at the telephoto end.

  The first lens having a small specific gravity is a positive meniscus lens L5 having a convex surface facing the object side of the second lens group G2 (first negative lens group).

  The second low specific gravity lens is a negative meniscus lens having the biconcave negative lens L1 of the first lens group G1 (first positive lens group) and the concave surface of the fourth lens group (second negative lens group). L9.

  As shown in FIG. 2, the zoom lens according to the second embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, and positive refraction. It has a third lens group G3 having a strong power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. In FIG. 2, r21, r22, and r23 are virtual planes.

  The first lens group G1 having positive refractive power is the first positive lens group, the second lens group G2 having negative refractive power is the first negative lens group, the third lens group G3 having positive refractive power is the second positive lens group, and negative refraction. The fourth lens group G4 for power is a second negative lens group, and the fifth lens group G5 for positive refractive power is a third positive lens group.

  During zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves to the image side, the third lens group G3 moves to the object side, and the fourth lens group G4. Moves to the object side, and the fifth lens group G5 is fixed. The aperture stop S is fixed, and the light amount is adjusted by changing the aperture size.

  In order from the object side, the first lens group G1 includes a biconcave negative lens L1, an optical path bending prism L2, and a biconvex positive lens L3. The second lens group G2 includes a biconcave negative lens L4 and a positive meniscus lens L5 having a convex surface directed toward the object side. The third lens group G3 includes a biconvex positive lens L6, and a cemented lens of a biconcave negative lens L7 and a biconvex positive lens L8. The fourth lens group G4 is composed of a biconcave negative lens L9. The fifth lens group G5 is composed of a biconvex positive lens L10.

  The aspherical surfaces are positive surfaces with the convex surfaces facing both surfaces of the biconcave negative lens L1 of the first lens group G1, both surfaces of the biconvex positive lens L3, both surfaces of the biconcave negative lens L4 of the second lens group G2, and the object side. Both surfaces of the meniscus lens L5, both surfaces of the biconvex positive lens L6 of the third lens group G3, the image side surface of the biconvex positive lens L8, both surfaces of the biconcave negative lens L9 of the fourth lens group G4, and the fifth lens group G5 A total of 15 surfaces including both surfaces of the biconvex positive lens L10 are used.

  In FIG. 2, the object side surface and the image side surface of the prism L are both flat, and there is a reflecting surface (not shown) between the two. The rear lens group is a third lens group G3, a fourth lens group G4, and a fifth lens group G5.

  The first lens group G1 is composed of two lens subgroups. The biconcave negative lens L1 is a negative lens subgroup having negative refractive power, and the biconvex positive lens L3 is a positive lens subgroup having positive refractive power.

  The second lens group G2 includes two lens subgroups, the biconcave negative lens L4 is a negative lens subgroup having negative refractive power, and the positive meniscus lens L5 having a convex surface facing the object side is a positive lens having positive refractive power. It is a subgroup.

  The distance on the optical axis from the aperture stop S to the third lens group G3 is wider at the wide-angle end than at the telephoto end.

  The first lens having a small specific gravity has a convex surface facing the biconvex positive lens L3 of the first lens group G1 (first positive lens group) and the object side of the second lens group G2 (first negative lens group). The positive meniscus lens L5.

  The second lens having a small specific gravity includes a biconcave negative lens L1 of the first lens group G1 (first positive lens group) and a biconcave negative lens L4 of the second lens group G2 (first negative lens group). , A biconcave negative lens L9 of the fourth lens group (second negative lens group).

  As shown in FIG. 3, the zoom lens according to the third exemplary embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, and positive refraction. It has a third lens group G3 having a strong power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. In FIG. 3, r21, r22, and r23 are virtual planes.

  The first lens group G1 having positive refractive power is the first positive lens group, the second lens group G2 having negative refractive power is the first negative lens group, the third lens group G3 having positive refractive power is the second positive lens group, and negative refraction. The fourth lens group G4 for power is a second negative lens group, and the fifth lens group G5 for positive refractive power is a third positive lens group.

  During zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves to the image side, the third lens group G3 moves to the object side, and the fourth lens group G4. Moves to the object side, and the fifth lens group G5 is fixed. The aperture stop S is fixed, and the light amount is adjusted by changing the aperture size.

  In order from the object side, the first lens group G1 includes a biconcave negative lens L1, an optical path bending prism L2, and a biconvex positive lens L3. The second lens group G2 includes a biconcave negative lens L4 and a positive meniscus lens L5 having a convex surface directed toward the object side. The third lens group G3 includes a biconvex positive lens L6, and a cemented lens of a biconcave negative lens L7 and a biconvex positive lens L8. The fourth lens group G4 includes a negative meniscus lens L9 having a concave surface directed toward the object side. The fifth lens group G5 is composed of a biconvex positive lens L10.

  The aspheric surfaces are positive surfaces with the convex surface facing the object side and both surfaces L1 of the biconcave negative lens of the first lens group G1, both surfaces of the biconvex positive lens L3, both surfaces of the biconcave negative lens L4 of the second lens group G2. Both surfaces of the meniscus lens L5, both surfaces of the biconvex positive lens L6 of the third lens group G3, the image side surface of the biconvex positive lens L8, both surfaces of the negative meniscus lens L9 with the concave surface facing the object side of the fourth lens group G4, A total of 15 surfaces including both surfaces of the biconvex positive lens L10 of the fifth lens group G5 are used.

  In FIG. 3, the object side surface and the image side surface of the prism are both flat, and there is a reflecting surface (not shown) between them. The rear lens group is a third lens group G3, a fourth lens group G4, and a fifth lens group G5.

  The first lens group G1 is composed of two lens subgroups. The biconcave negative lens L1 is a negative lens subgroup having negative refractive power, and the biconvex positive lens L3 is a positive lens subgroup having positive refractive power.

  The second lens group G2 is composed of two lens subgroups. The biconcave negative lens is a negative lens subgroup having L4 negative refractive power, and the positive meniscus lens L5 having a convex surface facing the object side is a positive lens having positive refractive power. It is a subgroup.

  The distance on the optical axis from the aperture stop S to the third lens group G3 is wider at the wide-angle end than at the telephoto end.

  The first lens having a small specific gravity has a convex surface facing the biconvex positive lens L3 of the first lens group G1 (first positive lens group) and the object side of the second lens group G2 (first negative lens group). The positive meniscus lens L5.

  The second lens having a small specific gravity includes a biconcave negative lens L1 of the first lens group G1 (first positive lens group) and a biconcave negative lens L4 of the second lens group G2 (first negative lens group). A negative meniscus lens L9 having a concave surface directed toward the object side of the fourth lens group (second negative lens group).

  As shown in FIG. 4, the zoom lens of Example 4 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, and positive refraction. It has a third lens group G3 having a strong power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. In FIG. 4, r14, r15, r23, r24, and r25 are virtual planes.

  The first lens group G1 having positive refractive power is the first positive lens group, the second lens group G2 having negative refractive power is the first negative lens group, the third lens group G3 having positive refractive power is the second positive lens group, and negative refraction. The fourth lens group G4 for power is a second negative lens group, and the fifth lens group G5 for positive refractive power is a third positive lens group.

  During zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves to the image side, the third lens group G3 moves to the object side, and the fourth lens group G4. Moves to the object side, and the fifth lens group G5 is fixed. The aperture stop S is fixed, and the light amount is adjusted by changing the aperture size.

  In order from the object side, the first lens group G1 includes a biconcave negative lens L1, an optical path bending prism L2, and a biconvex positive lens L3. The second lens group G2 includes a biconcave negative lens L4 and a positive meniscus lens L5 having a convex surface directed toward the object side. The third lens group G3 includes a biconvex positive lens L6, and a cemented lens of a biconcave negative lens L7 and a biconvex positive lens L8. The fourth lens group G4 is composed of a biconcave negative lens L9. The fifth lens group G5 is composed of a biconvex positive lens L10.

  The aspherical surfaces include both surfaces of the biconvex positive lens L3 of the first lens group G1, both surfaces of the biconcave negative lens L4 of the second lens group G2, both surfaces of the positive meniscus lens L5 with the convex surface facing the object side, and the third lens. Both sides of the biconvex positive lens L6 of the group G3, the image side surface of the biconvex positive lens L8, both sides of the biconcave negative lens L9 of the fourth lens group G4, and both sides of the biconvex positive lens L10 of the fifth lens group G5 A total of 13 surfaces are used.

  In FIG. 4, the object side surface and the image side surface of the prism are both flat, and there is a reflecting surface (not shown) between them. The rear lens group is a third lens group G3, a fourth lens group G4, and a fifth lens group G5.

  The first lens group G1 is composed of two lens subgroups. The biconcave negative lens L1 is a negative lens subgroup having negative refractive power, and the biconvex positive lens L3 is a positive lens subgroup having positive refractive power.

  The second lens group G2 includes two lens subgroups, the biconcave negative lens L4 is a negative lens subgroup having negative refractive power, and the positive meniscus lens L5 having a convex surface facing the object side is a positive lens having positive refractive power. It is a subgroup.

  The distance on the optical axis from the aperture stop S to the third lens group G3 is wider at the wide-angle end than at the telephoto end.

  The first lens having a small specific gravity is a biconvex positive lens L3 of the first lens group G1 (first positive lens group).

  The second lens having a small specific gravity is a biconcave negative lens L4 of the second lens group G2 (first negative lens group) and a biconcave negative lens L9 of the fourth lens group (second negative lens group). .

  As shown in FIG. 5, the zoom lens of Example 5 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, and positive refraction. It has a third lens group G3 having a strong power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. In FIG. 5, r14, r15, r23, r24, and r25 are virtual planes.

  The first lens group G1 having positive refractive power is the first positive lens group, the second lens group G2 having negative refractive power is the first negative lens group, the third lens group G3 having positive refractive power is the second positive lens group, and negative refraction. The fourth lens group G4 for power is a second negative lens group, and the fifth lens group G5 for positive refractive power is a third positive lens group.

  During zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves to the image side, the third lens group G3 moves to the object side, and the fourth lens group G4. Moves to the object side, and the fifth lens group G5 is fixed. The aperture stop S is fixed, and the light amount is adjusted by changing the aperture size.

  In order from the object side, the first lens group G1 includes a biconcave negative lens L1, an optical path bending prism L2, and a biconvex positive lens L3. The second lens group G2 includes a biconcave negative lens L4 and a positive meniscus lens L5 having a convex surface directed toward the object side. The third lens group G3 includes a biconvex positive lens L6, and a cemented lens of a biconcave negative lens L7 and a biconvex positive lens L8. The fourth lens group G4 is composed of a biconcave negative lens L9. The fifth lens group G5 is composed of a biconvex positive lens L10.

  The aspherical surfaces include both surfaces of the biconvex positive lens L3 of the first lens group G1, both surfaces of the biconcave negative lens L4 of the second lens group G2, both surfaces of the positive meniscus lens L5 with the convex surface facing the object side, and the third lens. Both sides of the biconvex positive lens L6 of the group G3, the image side surface of the biconvex positive lens L8, the image side surface of the biconcave negative lens L9 of the fourth lens group G4, both sides of the biconvex positive lens L10 of the fifth lens group G5, Are used for a total of 12 surfaces.

  In FIG. 5, the object side surface and the image side surface of the prism are both flat, and there is a reflecting surface (not shown) between them. The rear lens group is a third lens group G3, a fourth lens group G4, and a fifth lens group G5.

  The first lens group G1 is composed of two lens subgroups. The biconcave negative lens L1 is a negative lens subgroup having negative refractive power, and the biconvex positive lens L3 is a positive lens subgroup having positive refractive power.

  The second lens group G2 includes two lens subgroups, the biconcave negative lens L4 is a negative lens subgroup having negative refractive power, and the positive meniscus lens L5 having a convex surface facing the object side is a positive lens having positive refractive power. It is a subgroup.

  The distance on the optical axis from the aperture stop S to the third lens group G3 is wider at the wide-angle end than at the telephoto end.

  The first lens having a small specific gravity has a convex surface facing the biconvex positive lens L3 of the first lens group G1 (first positive lens group) and the object side of the second lens group G2 (first negative lens group). The positive meniscus lens L5.

  The second lens having a small specific gravity is a biconcave negative lens L4 of the second lens group G2 (first negative lens group) and a biconcave negative lens L9 of the fourth lens group (second negative lens group). .

  As shown in FIG. 6, the zoom lens of Example 6 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, and positive refraction. It has a third lens group G3 having a strong power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. In FIG. 6, r16, r17, r25, r26, r27 are virtual planes.

  The first lens group G1 having positive refractive power is the first positive lens group, the second lens group G2 having negative refractive power is the first negative lens group, the third lens group G3 having positive refractive power is the second positive lens group, and negative refraction. The fourth lens group G4 for power is a second negative lens group, and the fifth lens group G5 for positive refractive power is a third positive lens group.

  During zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves to the image side, the third lens group G3 moves to the object side, and the fourth lens group G4. Moves to the object side, and the fifth lens group G5 is fixed. The aperture stop S is fixed, and the light amount is adjusted by changing the aperture size.

  In order from the object side, the first lens group G1 includes a biconcave negative lens L1, an optical path bending prism L2, a biconvex positive lens L3, and a biconvex positive lens L4. The second lens group G2 includes a biconcave negative lens L5 and a positive meniscus lens L6 having a convex surface directed toward the object side. The third lens group G3 includes a biconvex positive lens L7, and a cemented lens of a biconcave negative lens L8 and a biconvex positive lens L9. The fourth lens group G4 includes a negative meniscus lens L10 having a concave surface directed toward the object side. The fifth lens group G5 is composed of a biconvex positive lens L11.

  The aspherical surfaces are positive surfaces with the convex surfaces facing both surfaces of the biconcave negative lens L1 of the first lens group G1, both surfaces of the biconvex positive lens L3, both surfaces of the biconcave negative lens L5 of the second lens group G2, and the object side. Both surfaces of the meniscus lens L6, both surfaces of the biconvex positive lens L7 of the third lens group G3, both surfaces of the biconvex positive lens L9, both surfaces of the negative meniscus lens L10 with the concave surface facing the object side of the fourth lens group G4, A total of 15 surfaces including both surfaces of the biconvex positive lens L11 of the five lens group G5 are used.

  In FIG. 6, the object side surface and the image side surface of the prism are both flat, and there is a reflecting surface (not shown) between the two. The rear lens group is a third lens group G3, a fourth lens group G4, and a fifth lens group G5.

  The first lens group G1 is composed of two lens subgroups. The biconcave negative lens L1 is a negative lens subgroup having negative refractive power, and the two biconvex positive lenses L3 and L4 are positive lens subgroups having positive refractive power. It is.

  The second lens group G2 is composed of two lens subgroups, the biconcave negative lens L5 is a negative lens subgroup having negative refractive power, and the positive meniscus lens L6 having a convex surface facing the object side is a positive lens having positive refractive power. It is a subgroup.

  The distance on the optical axis from the aperture stop S to the third lens group G3 is wider at the wide-angle end than at the telephoto end.

  The first lens having a small specific gravity has a convex surface facing the biconvex positive lens L3 of the first lens group G1 (first positive lens group) and the object side of the second lens group G2 (first negative lens group). The positive meniscus lens L6.

  The second lens having a small specific gravity has a concave surface directed toward the object side of the biconcave negative lens L1 of the first lens group G1 (first positive lens group) and the fourth lens group (second negative lens group). This is a negative meniscus lens L10.

  As shown in FIG. 7, the zoom lens according to the seventh embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group having a positive refractive power. G3, an aperture stop S, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. In FIG. 7, r23, r24, and r25 are virtual planes.

The first lens group G1 having positive refractive power is the first positive lens group, the second lens group G2 having negative refractive power is the first negative lens group, the third lens group G3 having positive refractive power is the second positive lens group , and negative the fifth lens group of the force G5 second negative lens group, the sixth lens group G 6 having a positive refractive power is the third positive lens group.

  During zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves to the image side, the third lens group G3 is fixed, and the fourth lens group G4 is on the object side. The fifth lens group G5 moves to the object side, and the sixth lens group G6 is fixed. The aperture stop S is fixed, and the light amount is adjusted by changing the aperture size.

  In order from the object side, the first lens group G1 includes a biconcave negative lens L1, an optical path bending prism L2, and a biconvex positive lens L3. The second lens group G2 includes a biconcave negative lens L4 and a positive meniscus lens L5 having a convex surface directed toward the object side. The third lens group G3 is composed of a biconvex positive lens L6. The fourth lens group G4 includes a biconvex positive lens L7, and a cemented lens of a biconcave negative lens L8 and a biconvex positive lens L9. The fifth lens group G5 includes a negative meniscus lens L10 having a concave surface directed toward the object side. The sixth lens group G6 includes a biconvex positive lens L11.

  The aspherical surface has a convex surface facing both surfaces of the biconcave negative lens L1 of the first lens group G1, both surfaces of the biconvex positive lens L3, both surfaces of the biconcave negative lens L4 of the second lens group G2, and the object side. Both surfaces of the positive meniscus lens L5, both surfaces of the biconvex positive lens L7 of the fourth lens group G4, the image side surface of the biconvex positive lens L9, and both surfaces of the negative meniscus lens L10 with the concave surface facing the object side of the fourth lens group G4 And a total of 15 surfaces including both surfaces of the biconvex positive lens L11 of the fifth lens group G5.

  In FIG. 7, the object side surface and the image side surface of the prism are both flat, and there is a reflecting surface (not shown) between them. The rear lens group is a third lens group G3, a fourth lens group G4, a fifth lens group G5, and a sixth lens group G6.

  The first lens group G1 is composed of two lens subgroups. The biconcave negative lens L1 is a negative lens subgroup having negative refractive power, and the biconvex positive lens L3 is a positive lens subgroup having positive refractive power.

  The second lens group G2 includes two lens subgroups, the biconcave negative lens L4 is a negative lens subgroup having negative refractive power, and the positive meniscus lens having a convex surface facing the object side is a positive lens having positive refractive power L5. It is a subgroup.

  The distance on the optical axis from the aperture stop S to the third lens group G3 is wider at the wide-angle end than at the telephoto end.

  The first lens having a small specific gravity has a convex surface facing the biconvex positive lens L3 of the first lens group G1 (first positive lens group) and the object side of the second lens group G2 (first negative lens group). The positive meniscus lens L5.

  The second lens having a small specific gravity includes a biconcave negative lens L1 of the first lens group G1 (first positive lens group) and a biconcave negative lens L4 of the second lens group G2 (first negative lens group). A negative meniscus lens L10 having a concave surface directed toward the object side of the fourth lens group (second negative lens group).

  As shown in FIG. 8, the zoom lens according to the eighth embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, and positive refraction. It has a third lens group G3 having a strong power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. In FIG. 8, r14, r15, r23, r24, and r25 are virtual planes.

  The first lens group G1 having positive refractive power is the first positive lens group, the second lens group G2 having negative refractive power is the first negative lens group, the third lens group G3 having positive refractive power is the second positive lens group, and negative refraction. The fourth lens group G4 for power is a second negative lens group, and the fifth lens group G5 for positive refractive power is a third positive lens group.

  During zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves to the image side, the third lens group G3 moves to the object side, and the fourth lens group G4. Moves to the object side, and the fifth lens group G5 is fixed. The aperture stop S is fixed, and the light amount is adjusted by changing the aperture size.

  In order from the object side, the first lens group G1 includes a biconcave negative lens L1, an optical path bending prism L2, and a biconvex positive lens L3. The second lens group G2 includes a biconcave negative lens L4 and a biconvex positive lens L5. The third lens group G3 includes a biconvex positive lens L6, and a cemented lens of a negative meniscus lens L7 having a convex surface on the object side and a biconvex positive lens L8. The fourth lens group G4 is composed of a biconcave negative lens L9. The fifth lens group G5 is composed of a biconvex positive lens L10.

  The aspheric surfaces are both surfaces of the biconcave negative lens L1 of the first lens group G1, both surfaces of the biconvex positive lens L3, both surfaces of the biconcave negative lens L4 of the second lens group G2, and both surfaces of the biconvex positive lens L5. Both surfaces of the biconvex positive lens L6 of the third lens group G3, the image side surface of the biconvex positive lens L8, both surfaces of the biconcave negative lens L9 of the fourth lens group G4, and the biconvex positive lens L10 of the fifth lens group G5. A total of 15 surfaces are used for both sides.

  In FIG. 8, the object side surface and the image side surface of the prism are both flat, and there is a reflecting surface (not shown) between them. The rear lens group is a third lens group G3, a fourth lens group G4, and a fifth lens group G5.

  The first lens group G1 is composed of two lens subgroups. The biconcave negative lens L1 is a negative lens subgroup having negative refractive power, and the biconvex positive lens L3 is a positive lens subgroup having positive refractive power.

  The second lens group G2 includes two lens subgroups, the biconcave negative lens L4 is a negative lens subgroup having negative refractive power, and the positive meniscus lens L5 having a convex surface facing the object side is a positive lens having positive refractive power. It is a subgroup.

  The distance on the optical axis from the aperture stop S to the third lens group G3 is wider at the wide-angle end than at the telephoto end.

  The first lens having a small specific gravity is the biconvex positive lens L5 of the second lens group G2 (first negative lens group).

  The second lens having a small specific gravity is a biconcave negative lens L4 of the second lens group G2 (first negative lens group) and a biconcave negative lens L9 of the fourth lens group (second negative lens group). .

  Below, the numerical data of each said Example are shown. Symbols other than the above, f is the focal length of the entire system, FB is the back focus, f1, f2,... Are the focal lengths of the respective lens groups, IH is the image height, FNo. Is an F number, ω is a half angle of view, r is a radius of curvature of each lens surface, d is a distance between the lens surfaces, nd is a refractive index of d-line of each lens, and νd is an Abbe number of each lens. The total lens length described later is obtained by adding back focus to the distance from the lens front surface to the lens final surface. FB (back focus) represents the distance from the last lens surface to the paraxial image plane in terms of air.

  The aspherical shape is represented by the following formula, where x is an optical axis with the light traveling direction being positive, and y is a direction orthogonal to the optical axis.

x = (y ² / r) / [1+ {1− (K + 1) (y / r) ² } ^1/2 ]
+ A ₄ y ⁴ + A ₆ y ⁶ + A ₈ y ⁸ + A ₁₀ y ¹⁰ + A ₁₂ y ¹²
Here, r is a paraxial radius of curvature, K is a conic coefficient, and A ₄ , A ₆ , A ₈ , A ₁₀ , and A ₁₂ are fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order aspheric coefficients. . In the aspheric coefficient, “e−n” (n is an integer) indicates “10 ⁻ⁿ ”.

  In the following numerical examples, the image height at the wide-angle end is smaller than the intermediate focal length state and the image height at the telephoto end. This is because a barrel-type distortion occurs. The value of the total angle of view (2ω) at the wide angle end in the numerical example displays the angle of view corresponding to the image height of the barrel-shaped effective imaging region.

  In the numerical examples, the numerical value indicating the reflecting surface of the reflecting member (reflecting prism) is omitted from the data, but the third surface indicates the incident surface of the reflecting member and the fourth surface indicates the exit surface of the reflecting member. Yes. Therefore, the reflecting surface exists between the third surface and the fourth surface.

Numerical example 1
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 * -11.404 0.900 1.63493 23.90
2 * 53.860 1.250
3 ∞ 11.200 1.84666 23.78
4 ∞ 0.200
5 * 9.601 2.722 1.58313 59.38
6 * -21.059 variable
7 * -9.131 0.600 1.58313 59.38
8 * 4.027 1.149
9 * 6.760 1.630 1.63493 23.90
10 * 31.669 variable
11 (Aperture) ∞ Variable
12 * 6.863 2.497 1.49710 81.56
13 * -12.559 4.283
14 -135.594 0.400 1.90366 31.32
15 4.700 2.635 1.58313 59.38
16 -9.700 Variable
17 * -5.608 0.600 1.53071 55.69
18 * -250.862 variable
19 * 26.727 2.496 1.53071 55.69
20 * -6.562 0.100
21 ∞ 0.100
22 ∞ 0.000
23 ∞ 0.300
24 ∞ 0.500 1.51633 64.14
25 ∞ 0.500
26 ∞ 0.500 1.51633 64.14
27 ∞ 0.370
Image plane (imaging plane) ∞

Aperture surface 11

Aspheric data first surface
K = 0.0000
A4 = 4.8867e-004, A6 = -1.6721e-006, A8 = 1.2307e-008, A10 = -3.9971e-011, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
Second side
K = 0.0000
A4 = 1.2672e-004, A6 = 1.8572e-006, A8 = 1.6233e-008, A10 = 8.0399e-012, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
5th page
K = 0.0000
A4 = -3.0628e-004, A6 = -5.2874e-006, A8 = 1.2921e-007, A10 = -1.7749e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
6th page
K = 0.0000
A4 = 2.7551e-005, A6 = -6.8014e-006, A8 = 2.1645e-007, A10 = -2.9018e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
7th page
K = 0.0000
A4 = 1.8162e-003, A6 = -7.2556e-005, A8 = 1.2042e-007, A10 = 4.9198e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
8th page
K = 0.0000
A4 = -2.6637e-003, A6 = 2.0862e-004, A8 = -1.6167e-005, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
9th page
K = 0.0000
A4 = -2.5693e-003, A6 = 1.2268e-004, A8 = 2.3777e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
10th page
K = 0.0000
A4 = -1.1527e-003, A6 = -7.5353e-006, A8 = 4.3449e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
12th page
K = 0.0000
A4 = -4.6429e-004, A6 = 7.4856e-008, A8 = 4.9091e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
13th page
K = 0.0000
A4 = 3.1565e-004, A6 = 2.0742e-006, A8 = 6.2215e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
17th page
K = 0.0000
A4 = 4.3471e-003, A6 = -1.1678e-004, A8 = 1.6183e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
18th page
K = 0.0000
A4 = 3.6487e-003, A6 = -8.0084e-005, A8 = -1.0022e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
19th page
K = 0.0000
A4 = -1.0551e-003, A6 = 7.8587e-005, A8 = -2.2761e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
20th page
K = 0.0000
A4 = 1.2619e-003, A6 = 6.5059e-006, A8 = -8.7752e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000

Zoom data
Wide-angle end Middle Telephoto end
f (mm) 5.100 11.149 24.478
F No. 3.683 5.242 5.885
2ω (angle of view) 78.95 39.96 18.72
FB (mm) -0.000 -0.000 -0.000

d6 0.753 4.773 7.911
d10 8.519 4.498 1.360
d11 8.416 4.778 0.500
d16 3.508 3.919 4.810
d18 1.972 5.199 8.587

Numerical example 2
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 * -23.628 1.000 1.63493 23.90
2 * 19.652 1.630
3 ∞ 9.600 1.84666 23.78
4 ∞ 0.200
5 * 10.070 2.772 1.53071 55.69
6 * -16.623 variable
7 * -7.516 0.702 1.53071 55.69
8 * 3.989 1.864
9 * 8.944 1.672 1.63493 23.90
10 * 116.518 Variable
11 (Aperture) ∞ Variable
12 * 5.525 3.370 1.49710 81.56
13 * -10.884 3.021
14 -16.817 0.400 1.90366 31.32
15 4.931 2.200 1.58313 59.38
16 * -9.700 variable
17 * -12.108 0.600 1.53071 55.69
18 * 15.878 variable
19 * 38.152 2.442 1.53071 55.69
20 * -6.737 0.100
21 ∞ 0.100
22 ∞ 0.040
23 ∞ 0.310
24 ∞ 0.500 1.51633 64.14
25 ∞ 0.500
26 ∞ 0.500 1.51633 64.14
27 ∞ 0.370
Image plane (imaging plane) ∞

Aperture surface 11

Aspheric data

First side
K = 0.0000
A4 = 1.2334e-004, A6 = -4.1031e-007, A8 = 2.9714e-009, A10 = 3.9450e-012, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
Second side
K = 0.0000
A4 = 5.9591e-005, A6 = 1.0979e-007, A8 = -3.2299e-010, A10 = 9.6222e-011, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
5th page
K = 0.0000
A4 = -2.0311e-004, A6 = -1.3308e-007, A8 = -4.7182e-008, A10 = 1.0156e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
6th page
K = 0.0000
A4 = 8.2223e-005, A6 = -6.2524e-007, A8 = -1.5116e-008, A10 = 7.1424e-010, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
7th page
K = 0.0000
A4 = 2.5880e-003, A6 = -9.2779e-005, A8 = 1.8759e-006, A10 = -7.5769e-009, A12 = 1.3401e-010,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
8th page
K = 0.0000
A4 = -2.6347e-003, A6 = 2.6002e-004, A8 = -1.2332e-005, A10 = -4.4875e-007, A12 = -2.0305e-17,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
9th page
K = 0.0000
A4 = -2.6188e-003, A6 = 1.4839e-004, A8 = 4.7980e-006, A10 = -5.4452e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
10th page
K = 0.0000
A4 = -1.5316e-003, A6 = 3.7614e-005, A8 = 5.0716e-006, A10 = -4.3057e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
12th page
K = 0.0000
A4 = -5.6964e-004, A6 = -5.9759e-006, A8 = -4.5718e-007, A10 = -4.9841e-009, A12 = 0.0000e + 000, A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
13th page
K = 0.0000
A4 = 6.7886e-004, A6 = -8.5657e-007, A8 = -7.2592e-007, A10 = 2.7596e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
16th page
K = 0.0000
A4 = 5.4934e-004, A6 = -3.8225e-006, A8 = 7.2022e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
17th page
K = 0.0000
A4 = 9.0650e-005, A6 = 1.8598e-005, A8 = -1.9297e-006, A10 = -2.8070e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
18th page
K = 0.0000
A4 = 2.6083e-004, A6 = 8.0671e-005, A8 = -9.6113e-006, A10 = 2.5452e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
19th page
K = 0.0000
A4 = -1.2004e-003, A6 = 8.6293e-005, A8 = -2.2816e-006, A10 = 7.7051e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
20th page
K = 0.0000
A4 = -2.9798e-005, A6 = 7.0421e-005, A8 = -1.5739e-006, A10 = -1.4524e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000

Zoom data
Wide-angle end Middle Telephoto end
f (mm) 5.100 11.150 24.479
F No. 3.151 4.406 6.411
2ω (angle of view) 72.51 36.99 17.44
FB (mm) 0.000 -0.000 0.001

d6 0.740 5.185 8.718
d10 8.678 4.233 0.700
d11 8.335 4.895 0.894
d16 2.850 3.003 3.380
d18 2.300 5.587 9.210

Numerical Example 3
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 * -11.511 0.928 1.63493 23.90
2 * 50.894 1.250
3 ∞ 11.200 1.84666 23.78
4 ∞ 0.200
5 * 10.309 2.741 1.53071 55.69
6 * -17.594 variable
7 * -8.305 0.600 1.53071 55.69
8 * 4.225 1.374
9 * 7.207 1.594 1.63493 23.90
10 * 34.700 variable
11 (Aperture) ∞ Variable
12 * 6.544 2.596 1.49710 81.56
13 * -13.683 4.281
14 -49.276 0.400 1.90366 31.32
15 4.700 2.559 1.58313 59.38
16 * -9.700 variable
17 * -5.770 0.600 1.53071 55.69
18 * -91.919 Variable
19 * 33.788 2.472 1.53071 55.69
20 * -6.436 0.100
21 ∞ 0.100
22 ∞ 0.000
23 ∞ 0.300
24 ∞ 0.500 1.51633 64.14
25 ∞ 0.500
26 ∞ 0.500 1.51633 64.14
27 ∞ 0.370
Image plane (imaging plane) ∞

Aperture surface 11

Aspheric data first surface
K = 0.0000
A4 = 4.9972e-004, A6 = -2.3425e-006, A8 = 1.3186e-008, A10 = -4.8194e-011, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
Second side
K = 0.0000
A4 = 1.6362e-004, A6 = 1.5947e-006, A8 = 1.5170e-008, A10 = -2.6936e-011, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
5th page
K = 0.0000
A4 = -2.9464e-004, A6 = -5.6622e-006, A8 = 1.7708e-007, A10 = -2.3738e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
6th page
K = 0.0000
A4 = 3.2514e-005, A6 = -7.3926e-006, A8 = 2.5331e-007, A10 = -3.4476e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
7th page
K = 0.0000
A4 = 1.9657e-003, A6 = -6.8617e-005, A8 = 2.1174e-007, A10 = 3.6314e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
8th page
K = 0.0000
A4 = -2.2882e-003, A6 = 1.9187e-004, A8 = -1.4852e-005, A10 = 1.1936e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
9th page
K = 0.0000
A4 = -2.1197e-003, A6 = 9.8756e-005, A8 = 1.0983e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
10th page
K = 0.0000
A4 = -9.1524e-004, A6 = -1.9018e-006, A8 = 3.2296e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
12th page
K = 0.0000
A4 = -4.4011e-004, A6 = -3.5561e-006, A8 = 1.4735e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
13th page
K = 0.0000
A4 = 3.1272e-004, A6 = -1.8102e-006, A8 = 2.8584e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
16th page
K = 0.0000
A4 = 8.3333e-005, A6 = 8.7092e-006, A8 = 0.0000e + 000, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
17th page
K = 0.0000
A4 = 3.2306e-003, A6 = 3.2226e-005, A8 = -4.8581e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
18th page
K = 0.0000
A4 = 2.8045e-003, A6 = 3.1408e-005, A8 = -2.0575e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
19th page
K = 0.0000
A4 = -1.0905e-003, A6 = 6.7868e-005, A8 = -1.9442e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
20th page
K = 0.0000
A4 = 1.1741e-003, A6 = 9.6689e-008, A8 = -5.6976e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000

Zoom data
Wide-angle end Middle Telephoto end
f (mm) 5.100 11.146 24.472
F No. 3.978 4.331 6.574
2w (Angle of view) 76.44 37.17 17.29
FB (mm) 0.000 0.001 0.001

d6 0.732 5.165 8.817
d10 9.445 5.012 1.360
d11 9.300 5.169 0.500
d16 3.389 3.609 4.961
d18 1.971 5.881 9.198

Numerical Example 4
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 -31.688 0.500 1.84666 23.78
2 24.341 1.300
3 ∞ 11.500 1.84666 23.78
4 ∞ 0.200
5 * 11.126 2.848 1.53071 55.69
6 * -15.073 variable
7 * -8.694 0.700 1.53071 55.69
8 * 4.255 2.691
9 * 11.459 1.957 1.82115 24.06
10 * 48.854 variable
11 (Aperture) ∞ Variable
12 * 5.934 3.000 1.49710 81.56
13 * -13.995 2.743
14 ∞ 0.000
15 ∞ 1.000
16 -19.937 0.400 1.90366 31.32
17 4.931 2.200 1.58313 59.38
18 * -9.700 variable
19 * -10.217 0.600 1.53071 55.69
20 * 24.121 variable
21 * 29.659 2.465 1.53071 55.69
22 * -6.981 0.100
23 ∞ 0.100
24 ∞ 0.030
25 ∞ 0.300
26 ∞ 0.500 1.51633 64.14
27 ∞ 0.500
28 ∞ 0.500 1.51633 64.14
29 ∞ 0.370
Image plane (imaging plane) ∞

Aperture surface 11

Aspheric data 5th surface
K = 0.0000
A4 = -1.6106e-004, A6 = -2.2807e-008, A8 = 3.1983e-009, A10 = -1.4330e-010, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
6th page
K = 0.0000
A4 = 8.7762e-005, A6 = 3.3101e-007, A8 = -3.9786e-009, A10 = -1.1715e-011, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
7th page
K = 0.0000
A4 = 2.2061e-003, A6 = -5.2881e-005, A8 = -1.1797e-007, A10 = 1.6891e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
8th page
K = 0.0000
A4 = -1.7160e-003, A6 = 1.7338e-004, A8 = -8.9580e-006, A10 = -1.7749e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
9th page
K = 0.0000
A4 = -1.2922e-003, A6 = 5.0235e-005, A8 = 5.9654e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
10th page
K = 0.0000
A4 = -8.4366e-004, A6 = 1.0358e-005, A8 = 1.1793e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
12th page
K = 0.0000
A4 = -4.0643e-004, A6 = -6.2770e-006, A8 = 1.1928e-007, A10 = -1.9111e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
13th page
K = 0.0000
A4 = 4.3811e-004, A6 = -1.9065e-007, A8 = -1.3069e-007, A10 = -3.4151e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
18th page
K = 0.0000
A4 = 5.8554e-004, A6 = 3.6172e-005, A8 = 0.0000e + 000, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
19th page
K = 0.0000
A4 = 2.4536e-003, A6 = 8.2125e-005, A8 = -9.1481e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
20th page
K = 0.0000
A4 = 2.4222e-003, A6 = 7.8165e-005, A8 = -7.2362e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
21st page
K = 0.0000
A4 = -1.0766e-003, A6 = 7.1611e-005, A8 = -1.5864e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
22nd page
K = 0.0000
A4 = 3.3290e-004, A6 = 4.8169e-005, A8 = -1.2396e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000

Zoom data
Wide-angle end Middle Telephoto end
f (mm) 5.100 11.150 24.479
F No. 3.533 4.777 6.508
2w (angle of view) 74.48 37.07 17.41
FB (mm) 0.000 0.000 0.000

d6 0.500 5.211 9.548
d10 10.408 5.697 1.360
d11 7.799 4.092 0.500
d18 3.595 3.572 3.212
d20 2.196 5.926 9.877

Numerical Example 5
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 -40.120 0.500 2.00069 25.46
2 30.215 1.130
3 ∞ 9.700 1.84666 23.78
4 ∞ 0.200
5 * 11.021 2.882 1.53071 55.69
6 * -15.557 variable
7 * -8.112 0.700 1.53071 55.69
8 * 4.088 2.326
9 * 10.305 1.620 1.63493 23.90
10 * 151.809 Variable
11 (Aperture) ∞ Variable
12 * 5.391 3.170 1.49710 81.56
13 * -11.653 1.733
14 ∞ 0.000
15 ∞ 1.000
16 -30.020 0.400 1.90366 31.32
17 4.931 2.200 1.58313 59.38
18 * -9.700 variable
19 -11.009 0.600 1.53071 55.69
20 * 7.864 variable
21 * 20.112 2.567 1.53071 55.69
22 * -7.642 0.100
23 ∞ 0.100
24 ∞ 0.030
25 ∞ 0.300
26 ∞ 0.500 1.51633 64.14
27 ∞ 0.500
28 ∞ 0.500 1.51633 64.14
29 ∞ 0.370
Image plane (imaging plane) ∞

Aperture surface 11

Aspheric data 5th surface
K = 0.0000
A4 = -1.6027e-004, A6 = 1.8897e-007, A8 = -9.8151e-009, A10 = 3.0750e-011, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
6th page
K = 0.0000
A4 = 8.5188e-005, A6 = 4.3598e-007, A8 = -1.0804e-008, A10 = 9.5901e-011, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
7th page
K = 0.0000
A4 = 2.7889e-003, A6 = -8.3570e-005, A8 = 1.0504e-006, A10 = -1.1420e-008, A12 = 4.9094e-010,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
8th page
K = 0.0000
A4 = -1.8509e-003, A6 = 2.1469e-004, A8 = -6.0887e-006, A10 = -5.2565e-007, A12 = -2.0287e-017, A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
9th page
K = 0.0000
A4 = -2.6233e-003, A6 = 9.9715e-005, A8 = 1.0603e-006, A10 = -1.8643e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
10th page
K = 0.0000
A4 = -1.7284e-003, A6 = 1.9504e-005, A8 = 1.7897e-006, A10 = -4.3953e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
12th page
K = 0.0000
A4 = -5.2312e-004, A6 = -5.9748e-006, A8 = -2.9611e-007, A10 = -1.8032e-008, A12 = 0.0000e + 000, A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
13th page
K = 0.0000
A4 = 7.9611e-004, A6 = -6.0960e-007, A8 = -9.3249e-007, A10 = 2.8764e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
18th page
K = 0.0000
A4 = 8.1470e-004, A6 = 1.7490e-005, A8 = 5.7051e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
20th page
K = 0.0000
A4 = 1.2125e-004, A6 = 3.4415e-005, A8 = -5.5080e-006, A10 = 2.1978e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
21st page
K = 0.0000
A4 = 1.9795e-005, A6 = 1.7883e-005, A8 = -1.1442e-006, A10 = 2.1724e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
22nd page
K = 0.0000
A4 = 1.3430e-003, A6 = -4.1407e-005, A8 = 7.3715e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000

Zoom data
Wide-angle end Middle Telephoto end
f (mm) 5.100 11.150 24.478
F No. 3.508 4.707 6.539
2w (angle of view) 74.32 37.17 17.46
FB (mm) 0.000 0.000 0.001

d6 0.514 5.687 9.774
d10 9.960 4.787 0.700
d11 6.754 3.819 0.500
d18 2.418 2.836 3.235
d20 2.726 5.243 8.164

Numerical Example 6
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 * -18.198 0.700 1.63493 23.90
2 * 28.716 1.523
3 ∞ 9.700 1.84666 23.78
4 ∞ 0.200
5 * 22.225 1.700 1.53071 55.69
6 * -42.144 0.100
7 19.096 1.920 1.60300 65.44
8 -28.904 variable
9 * -9.944 0.550 1.61881 63.85
10 * 3.874 1.060
11 * 7.847 1.406 1.63493 23.90
12 * 63.708 variable
13 (Aperture) ∞ Variable
14 * 6.004 2.995 1.49710 81.56
15 * -10.669 2.019
16 ∞ 0.000
17 ∞ 1.000
18 -149.962 0.350 1.90366 31.32
19 4.931 2.395 1.58313 59.38
20 * -9.400 variable
21 * -4.439 0.600 1.53071 55.69
22 * -44.564 variable
23 * 37.844 2.143 1.53071 55.69
24 * -7.327 0.100
25 ∞ 0.100
26 ∞ 0.000
27 ∞ 0.300
28 ∞ 0.500 1.51633 64.14
29 ∞ 0.500
30 ∞ 0.500 1.51633 64.14
31 ∞ 0.370
Image plane (imaging plane) ∞

Aperture surface 13

Aspheric data first surface
K = 0.0000
A4 = 3.5910e-004, A6 = -1.5689e-006, A8 = 3.3159e-009, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
Second side
K = 0.0000
A4 = 2.7242e-004, A6 = 2.6470e-007, A8 = 3.7041e-008, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
5th page
K = 0.0000
A4 = -3.1240e-004, A6 = -4.9883e-006, A8 = 5.3872e-008, A10 = 1.3165e-010, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
6th page
K = 0.0000
A4 = -1.8909e-004, A6 = -5.2332e-006, A8 = 4.4809e-008, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
9th page
K = 0.0000
A4 = 1.5041e-003, A6 = -6.3720e-005, A8 = 2.2526e-007, A10 = 1.0477e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
10th page
K = 0.0000
A4 = -2.1206e-003, A6 = 1.3276e-004, A8 = -6.5650e-006, A10 = -1.0229e-006, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
11th page
K = 0.0000
A4 = -2.3501e-003, A6 = 9.2938e-005, A8 = -8.9496e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
12th page
K = 0.0000
A4 = -1.5850e-003, A6 = -4.2787e-005, A8 = 1.7115e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
14th page
K = 0.0000
A4 = -5.7540e-004, A6 = -4.5954e-006, A8 = 1.0108e-007, A10 = -7.7570e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
15th page
K = 0.0000
A4 = 6.7048e-004, A6 = -5.8899e-006, A8 = 1.5882e-007, A10 = -3.9850e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
20th page
K = 0.0000
A4 = -2.5023e-004, A6 = 5.0240e-005, A8 = 2.1356e-006, A10 = -4.4834e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
21st page
K = 0.0000
A4 = 4.1362e-003, A6 = 2.7400e-004, A8 = -1.1371e-005, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
22nd page
K = 0.0000
A4 = 3.6322e-003, A6 = 9.4347e-005, A8 = -7.0150e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
23rd page
K = 0.0000
A4 = 3.3787e-004, A6 = 1.0126e-005, A8 = -1.2002e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
24th page
K = 0.0000
A4 = 2.7327e-003, A6 = -8.6075e-005, A8 = 5.1667e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000

Zoom data
Wide-angle end Middle Telephoto end
f (mm) 5.100 11.149 24.480
F No. 3.603 4.127 6.575
2w (angle of view) 74.25 37.03 17.23
FB (mm) 0.000 0.000 0.006

d8 0.800 5.100 7.406
d12 7.966 3.667 1.360
d13 7.535 4.969 0.500
d20 2.561 2.934 3.613
d22 2.907 5.099 8.883

Numerical Example 7
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 * -14.503 1.000 1.63493 23.90
2 * 74.969 1.250
3 ∞ 11.500 1.84666 23.78
4 ∞ 0.200
5 * 14.422 2.390 1.53071 55.69
6 * -14.445 variable
7 * -8.001 0.700 1.53071 55.69
8 * 3.969 1.713
9 * 6.005 1.302 1.63493 23.90
10 * 12.119 Variable
11 31.266 0.700 1.72000 41.98
12 -42.026 0.640
13 (Aperture) ∞ Variable
14 * 6.701 4.744 1.49710 81.56
15 * -19.645 1.469
16 -30.900 0.673 1.90366 31.32
17 4.931 2.422 1.58313 59.38
18 * -9.890 variable
19 * -5.791 0.600 1.53071 55.69
20 * -183.049 variable
21 * 25.035 2.625 1.53071 55.69
22 * -6.801 0.100
23 ∞ 0.100
24 ∞ 0.000
25 ∞ 0.785
26 ∞ 0.500 1.51633 64.14
27 ∞ 0.500
28 ∞ 0.500 1.51633 64.14
29 ∞ 0.370
Image plane (imaging plane) ∞

Aperture surface 13

Aspheric data
First side
K = 0.0000
A4 = 2.2771e-004, A6 = 2.8251e-006, A8 = -2.6927e-008, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
Second side
K = 0.0000
A4 = 1.6948e-004, A6 = 3.5161e-006, A8 = 4.8992e-008, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
5th page
K = 0.0000
A4 = -1.5536e-004, A6 = -4.2184e-006, A8 = 1.1067e-007, A10 = -8.4449e-010, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
6th page
K = 0.0000
A4 = 3.0475e-005, A6 = -4.3313e-006, A8 = 1.0109e-007, A10 = -8.0372e-010, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
7th page
K = 0.0000
A4 = 2.2842e-003, A6 = -5.0757e-005, A8 = -3.0632e-007, A10 = 3.6490e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
8th page
K = 0.0000
A4 = -2.3954e-003, A6 = 1.3979e-004, A8 = -9.1577e-006, A10 = -3.5923e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
9th page
K = 0.0000
A4 = -2.1094e-003, A6 = 6.6145e-005, A8 = -5.2890e-007, A10 = -2.2237e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
10th page
K = 0.0000
A4 = -8.3168e-004, A6 = 3.2335e-006, A8 = 6.0508e-007, A10 = -2.0665e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
14th page
K = 0.0000
A4 = -1.9406e-004, A6 = -4.8533e-006, A8 = 6.9648e-008, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
15th page
K = 0.0000
A4 = 3.6640e-004, A6 = -1.1425e-005, A8 = 4.3805e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
18th page
K = 0.0000
A4 = -9.5646e-005, A6 = 6.6259e-005, A8 = -4.8082e-006, A10 = 5.8594e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
19th page
K = 0.0000
A4 = 5.5183e-003, A6 = 1.4495e-004, A8 = -2.8741e-005, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
20th page
K = 0.0000
A4 = 5.0156e-003, A6 = 1.4579e-004, A8 = -2.2769e-005, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
21st page
K = 0.0000
A4 = -1.1323e-003, A6 = 2.8866e-005, A8 = -1.8637e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
22nd page
K = 0.0000
A4 = 4.8645e-004, A6 = -9.5063e-006, A8 = 4.2730e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000

Zoom data
Wide-angle end Middle Telephoto end
f (mm) 5.100 11.149 24.479
F No. 4.091 5.689 6.665
2w (angle of view) 74.24 38.21 17.17
FB (mm) 0.001 0.001 0.001

d6 0.514 5.188 10.730
d10 11.576 6.902 1.360
d13 9.087 3.145 0.500
d18 3.369 3.252 5.428
d20 1.673 7.731 8.200

Numerical Example 8
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 * -20.883 0.500 1.85026 32.27
2 * 41.037 1.300
3 ∞ 11.500 1.84666 23.78
4 ∞ 0.200
5 * 12.001 2.292 1.55332 71.68
6 * -16.307 variable
7 * -6.026 0.700 1.53071 55.69
8 * 4.298 2.251
9 * 9.709 1.696 1.74000 33.00
10 * -545.261 variable
11 (Aperture) ∞ Variable
12 * 6.468 2.687 1.49710 81.56
13 * -15.783 2.638
14 ∞ 0.000
15 ∞ 1.000
16 58.313 0.400 1.91082 35.25
17 4.931 2.251 1.49700 81.54
18 * -13.639 variable
19 * -6.680 0.632 1.53071 55.69
20 * 2249.607 variable
21 * 29.622 2.625 1.49700 81.54
22 * -6.094 0.100
23 ∞ 0.100
24 ∞ 0.030
25 ∞ 0.300
26 ∞ 0.500 1.51633 64.14
27 ∞ 0.500
28 ∞ 0.500 1.51633 64.14
29 ∞ 0.370
Image plane (imaging plane) ∞

Aperture surface 11

Aspheric data
First side
K = 0.0000
A4 = 2.2584e-004, A6 = -8.4411e-007, A8 = 2.1742e-010, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
Second side
K = 0.0000
A4 = 1.7966e-004, A6 = 9.7989e-007, A8 = -6.3676e-009, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
5th page
K = 0.0000
A4 = -1.7569e-004, A6 = -1.2790e-006, A8 = 3.9206e-008, A10 = -3.8393e-010, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
6th page
K = 0.0000
A4 = 4.4552e-005, A6 = -1.7066e-006, A8 = 4.5289e-008, A10 = -3.9478e-010, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
7th page
K = 0.0000
A4 = 3.2106e-003, A6 = -7.0171e-005, A8 = -2.1867e-007, A10 = 5.2394e-008, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
8th page
K = 0.0000
A4 = -3.1055e-003, A6 = 2.9811e-004, A8 = -2.1928e-005, A10 = 3.2010e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
9th page
K = 0.0000
A4 = -1.7771e-003, A6 = 6.3729e-005, A8 = 9.4242e-007, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
10th page
K = 0.0000
A4 = -7.5115e-004, A6 = -1.4955e-007, A8 = 1.9826e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
12th page
K = 0.0000
A4 = -3.6539e-004, A6 = -8.3818e-006, A8 = -1.8118e-007, A10 = 4.5343e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
13th page
K = 0.0000
A4 = 3.3756e-004, A6 = -1.1872e-005, A8 = 7.3857e-008, A10 = 8.9736e-009, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
18th page
K = 0.0000
A4 = 2.0844e-004, A6 = 6.4187e-005, A8 = 1.2920e-006, A10 = -2.9443e-007, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
19th page
K = 0.0000
A4 = 5.4393e-003, A6 = 1.3117e-004, A8 = -2.3404e-005, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
20th page
K = 0.0000
A4 = 5.0543e-003, A6 = 1.3245e-004, A8 = -2.0692e-005, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
21st page
K = 0.0000
A4 = -1.3721e-003, A6 = 9.7943e-005, A8 = -2.9856e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000
22nd page
K = 0.0000
A4 = 9.2047e-004, A6 = 3.4950e-005, A8 = -1.4447e-006, A10 = 0.0000e + 000, A12 = 0.0000e + 000,
A14 = 0.0000e + 000, A16 = 0.0000e + 000, A18 = 0.0000e + 000, A20 = 0.0000e + 000

Zoom data
Wide-angle end Middle Telephoto end
f (mm) 5.100 11.150 24.480
F No. 3.769 4.825 6.276
2w (angle of view) 74.24 37.06 17.36
FB (mm) 0.000 0.000 -0.000

d6 0.947 6.134 11.204
d10 11.617 6.430 1.360
d11 7.294 3.671 0.500
d18 4.291 4.066 3.200
d20 1.780 5.627 9.665

The values corresponding to the conditional expressions in each example are shown below.
Conditional expression (1) (2) (3) (4) (5) (8)
First Example 0.274 3.546 2.681 0.442 0.505 0.901
Second Example 0.498 4.391 3.422 0.525 0.428 0.973
Third Example 0.342 4.346 3.125 0.475 0.431 0.787
Fourth embodiment 0.694 4.248 3.587 0.549 0.469 1.065
Example 5 0.602 4.660 2.274 0.349 0.365 1.128
Example 6 0.275 3.744 2.518 0.381 0.483 1.163
Example 7 0.444 4.920 3.054 0.461 0.404 1.499
Eighth Example 0.583 4.542 3.358 0.513 0.441 0.572

First embodiment
Lens Refractive power code Material Conditional expression (6) Conditional expression (7)
1st positive lens group L1 negative Polycarbonate 1.2 1.63493
First negative lens group L5 positive Polycarbonate 1.2 1.63493
Second negative lens unit L9 Negative Cycloolefin polymer 1.01 1.53071

Second embodiment
Lens Refractive power code Material Conditional expression (6) Conditional expression (7)
1st positive lens group L1 negative Polycarbonate 1.2 1.63493
L3 positive cycloolefin polymer 1.01 1.53071
First negative lens group L4 Negative Cycloolefin polymer 1.01 1.53071
L5 Positive Polycarbonate 1.2 1.63493
Second negative lens unit L9 Negative Cycloolefin polymer 1.01 1.53071

Third embodiment
Lens Power code Material Conditional expression (6) Conditional expression (7)
1st positive lens group L1 negative Polycarbonate 1.2 1.63493
L3 positive cycloolefin polymer 1.01 1.53071
First negative lens group L4 Negative Cycloolefin polymer 1.01 1.53071
L5 Positive Polycarbonate 1.2 1.63493
Second negative lens unit L9 Negative Cycloolefin polymer 1.01 1.53071

Fourth embodiment
Lens Power code Material Conditional expression (6) Conditional expression (7)
First positive lens group L3 positive cycloolefin polymer 1.01 1.53071
First negative lens group L4 Negative Cycloolefin polymer 1.01 1.53071
Second negative lens unit L9 Negative Cycloolefin polymer 1.01 1.53071

Example 5
Lens Refractive power code Material Conditional expression (6) Conditional expression (7)
First positive lens group L3 positive cycloolefin polymer 1.01 1.53071
First negative lens group L4 Negative Cycloolefin polymer 1.01 1.53071
L5 Positive Polycarbonate 1.2 1.63493
Second negative lens unit L9 Negative Cycloolefin polymer 1.01 1.53071

Sixth embodiment
Lens Refractive power code Material Conditional expression (6) Conditional expression (7)
1st positive lens group L1 negative Polycarbonate 1.2 1.63493
L3 positive cycloolefin polymer 1.01 1.53071
First negative lens group L6 Positive Polycarbonate 1.2 1.63493
Second negative lens group L10 Negative Cycloolefin polymer 1.01 1.53071

Example 7
Lens Refractive power code Material Conditional expression (6) Conditional expression (7)
1st positive lens group L1 negative Polycarbonate 1.2 1.63493
L3 positive cycloolefin polymer 1.01 1.53071
First negative lens group L4 Negative Cycloolefin polymer 1.01 1.53071
L5 Positive Polycarbonate 1.2 1.63493
Second negative lens group L10 Negative Cycloolefin polymer 1.01 1.53071

Example 8
Lens Refractive power code Material Conditional expression (6) Conditional expression (7)
First negative lens group L4 Negative Cycloolefin polymer 1.01 1.53071
L5 Positive Episulfide resin 1.46 1.74
Second negative lens unit L9 Negative Cycloolefin polymer 1.01 1.53071

  Aberration diagrams at the time of focusing on an object point at infinity in Examples 1 to 8 are shown in FIGS. In each figure, “FIY” indicates the maximum image height.

  In these aberration diagrams, (a), (b), (c), and (d) indicate spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (at the wide-angle end), respectively. CC).

  Further, (e), (f), (g), and (h) are respectively spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) in the intermediate focal length state. Indicates.

  Further, (i), (j), (k), and (l) respectively indicate spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) at the telephoto end. .

  Next, the values of the conditional expressions in each example are listed.

(Correction of distortion)
By the way, when the zoom lens of the present invention is used, image distortion is digitally corrected electrically. The basic concept for digitally correcting image distortion will be described below.

  For example, as shown in FIG. 17, the magnification on the circumference (image height) of the radius R inscribed in the long side of the effective imaging surface around the intersection of the optical axis and the imaging surface is fixed, and this circumference is The standard for correction. Then, correction is performed by moving each point on the circumference (image height) of any other radius r (ω) in a substantially radial direction and concentrically so as to have the radius r ′ (ω). To do.

For example, in FIG. 17, a point P ₁ on the circumference of an arbitrary radius r ₁ (ω) located inside the circle of radius R is the radius r ₁ ′ (ω) to be corrected toward the center of the circle. It is moved to a point P ₂ on the circumference. A point Q ₁ on the circumference of an arbitrary radius r ₂ (ω) located outside the circle of radius R is a circle of radius r ₂ ′ (ω) to be corrected in a direction away from the center of the circle. It is moved to the point Q ₂ on the circumference.

Here, r ′ (ω) can be expressed as follows.
r ′ (ω) = α · f · tan ω
here,
ω is the half angle of view of the subject,
f is the focal length of the imaging optical system (in the present invention, the zoom lens),
α is 0 or more and 1 or less,
It is.

Here, if the ideal image height corresponding to the circle (image height) of the radius R is Y,
α = R / Y = R / (f · tan ω),
It becomes.

  The optical system is ideally rotationally symmetric with respect to the optical axis, that is, distortion is also generated rotationally symmetric with respect to the optical axis. Therefore, as described above, when the optically generated distortion aberration is electrically corrected, the radius inscribed in the long side of the effective imaging surface around the intersection of the optical axis and the imaging surface on the reproduced image. The magnification on the circumference of the circle of R (image height) is fixed, and the other points on the circumference of the circle (image height) of radius r (ω) are moved in a substantially radial direction to obtain a radius r ′ ( If correction can be performed by moving the concentric circles so that ω), it is considered advantageous in terms of data amount and calculation amount.

  However, the optical image is no longer a continuous amount (due to sampling) when captured by the electronic image sensor. Therefore, strictly speaking, the circle with the radius R drawn on the optical image is not an accurate circle unless the pixels on the electronic image sensor are arranged radially.

  That is, in the shape correction of the image data represented for each discrete coordinate point, there is no circle that can fix the magnification. Therefore, it is preferable to use a method of determining the coordinates (Xi ′, Yj ′) of the movement destination for each pixel (Xi, Yj). When two or more points (Xi, Yj) have moved to the coordinates (Xi ′, Yj ′), the average value of the values of each pixel is taken. If there is no moving point, interpolation may be performed using the values of the coordinates (Xi ′, Yj ′) of some surrounding pixels.

  Such a method is particularly distorted with respect to the optical axis due to manufacturing errors of an optical system and an electronic imaging device in an electronic imaging apparatus having a zoom lens, and the circle with the radius R drawn on the optical image is It is effective for correction when it becomes asymmetric. Further, it is effective for correction when a geometric distortion or the like occurs when a signal is reproduced as an image in an image sensor or various output devices.

  In the electronic imaging apparatus of the present invention, in order to calculate the correction amount r ′ (ω) −r (ω), r (ω), that is, the relationship between the half field angle and the image height, or the real image height r and the ideal image height. The relationship between r ′ / α may be recorded on a recording medium built in the electronic imaging apparatus.

  Note that the radius R preferably satisfies the following conditional expression so that the image after distortion correction does not have an extremely short amount of light at both ends in the short side direction.

0 ≦ R ≦ 0.6Ls
Here, Ls is the length of the short side of the effective imaging surface.

Preferably, the radius R satisfies the following conditional expression.
0.3Ls ≦ R ≦ 0.6Ls
Furthermore, it is most advantageous to make the radius R coincide with the radius of the inscribed circle in the short side direction of the substantially effective imaging surface. In the case of correction in which the magnification is fixed in the vicinity of the radius R = 0, that is, in the vicinity of the axis, there is a slight disadvantage in terms of image quality, but the effect of reducing the size is secured even if the angle of view is widened. it can.

The focal length section that needs to be corrected is divided into several focal zones. And approximately near the telephoto end in the divided focal zone,
r ′ (ω) = α · f · tan ω
You may correct | amend with the same correction amount as the case where the correction result which satisfies is obtained.

  Here, in this case, some barrel distortion remains at the wide-angle end in the divided focal zone. Further, if the number of divided zones is increased, it becomes unnecessary to store extraneous data necessary for correction on the recording medium, which is not preferable. Therefore, one or several coefficients related to each focal length in the divided focal zone are calculated in advance. This coefficient may be determined on the basis of simulation or actual measurement.

And approximately near the telephoto end in the divided zone,
r ′ (ω) = α · f · tan ω
It is also possible to calculate a correction amount when a correction result satisfying the above is obtained, and uniformly multiply the correction amount for each focal distance to obtain a final correction amount.

By the way, if there is no distortion in the image obtained by imaging an object at infinity,
f = y / tan ω
Is established.
Here, y is the height (image height) of the image point from the optical axis, f is the focal length of the imaging system (in the present invention, the zoom lens), and ω is the image point connecting from the center on the imaging surface to the y position. Is an angle (subject half-field angle) with respect to the optical axis in the object direction corresponding to.

If the imaging system has barrel distortion,
f> y / tan ω
It becomes. That is, if the focal length f of the imaging system and the image height y are constant, the value of ω increases.

(Digital camera)
The zoom lens of the present invention as described above forms an object image, and the image can be received by an electronic image sensor such as a CCD. The embodiment is illustrated below.

  18 to 20 are conceptual diagrams of a configuration in which the zoom lens according to the present invention is incorporated in a photographing optical system 141 of a digital camera. 18 is a front perspective view showing the external appearance of the digital camera 140, FIG. 19 is a rear perspective view thereof, and FIG. 20 is a conceptual diagram showing an internal configuration of the digital camera 140. FIG. 20 is a view of a cross section orthogonal to the vertical direction of the digital camera 140 as viewed from above, and the viewfinder optical system and front and rear cover glasses are not shown. Further, in the paper surface direction of FIG. 20, the long side direction of the effective imaging area of the CCD 149 and the thickness direction of the digital camera 140 coincide with each other.

  In this example, the digital camera 140 includes a photographing optical system 141 having a photographing optical path 142, a finder optical system 143 having a finder optical path 144, a shutter 145, a flash 146, a liquid crystal display monitor 147, and the like. When the shutter 145 disposed in the position is pressed, photographing is performed through the photographing optical system 141, for example, the optical path bending zoom lens according to the first embodiment in conjunction therewith. An object image formed by the photographing optical system 141 is formed on the imaging surface of the CCD 149 through a near-infrared cut filter and an optical low-pass filter F. The object image received by the CCD 149 is displayed as an electronic image on a liquid crystal display monitor 147 provided on the back of the camera via the processing means 151. Further, the processing means 151 is connected to a recording means 152 so that a photographed electronic image can be recorded. The recording unit 152 may be provided separately from the processing unit 151, or may be configured to perform recording / writing electronically using a flexible disk, a memory card, an MO, or the like. Further, a C-MOS sensor may be used in place of the CCD 149.

  Further, a finder objective optical system (not shown) is disposed on the finder optical path 144. An object image formed by the finder objective optical system is formed on a field frame (not shown) of a Porro prism (not shown) which is an image erecting member. Behind this polyprism is an eyepiece optical system (not shown) that guides the erect image to the observer eyeball E. Note that cover members 150 are disposed on the entrance side of the photographing optical system 141 and the objective optical system for the viewfinder and on the exit side of the eyepiece optical system, respectively.

  The digital camera 140 configured in this manner is a zoom lens that has a high zoom ratio of about 4 times, a bright zoom ratio, and high optical performance. Therefore, the digital camera 140 is high-performance and inexpensive in the depth direction. A digital camera can be realized.

In addition, in the example of FIG. 20, although a parallel plane board is arrange | positioned as the cover member 150, you may omit.
In this configuration, the reflecting surface is arranged so that the long side direction of the imaging surface of the imaging element is parallel to the surface including the optical axis. However, the present invention is not limited to this, and the reflecting surface is arranged so that the short side direction of the imaging surface of the imaging device and the surface including the optical axis are parallel.

(Internal circuit configuration)
FIG. 21 is a block diagram showing the internal circuitry of the main part of the digital camera 140. In the following description, the processing means includes, for example, the CDS / ADC unit 124, the temporary storage memory 117, the image processing unit 118, and the like, and the storage means includes, for example, the storage medium unit 119.

  As shown in FIG. 21, the digital camera 140 is connected to the operation unit 112, the control unit 113 connected to the operation unit 112, and the control signal output port of the control unit 113 via buses 114 and 115. An imaging drive circuit 116, a temporary storage memory 117, an image processing unit 118, a storage medium unit 119, a display unit 120, and a setting information storage memory unit 121 are provided.

  The temporary storage memory 117, the image processing unit 118, the storage medium unit 119, the display unit 120, and the setting information storage memory unit 121 are configured so that data can be input or output with each other via the bus 122. In addition, a CCD 149 and a CDS / ADC unit 124 are connected to the imaging drive circuit 116.

  The operation unit 112 includes various input buttons and switches, and is a circuit that notifies the control unit of event information input from the outside (camera user) via these input buttons and switches.

  The control unit 113 is a central processing unit composed of, for example, a CPU and the like. The control unit 113 includes a program memory (not shown) and is input from the camera user via the operation unit 112 according to a program stored in the program memory. This is a circuit that controls the entire digital camera 140 in response to an instruction command.

  The CCD 149 receives an object image formed through the photographing optical system 141 according to the present invention. The CCD 149 is an image pickup element that is driven and controlled by the image pickup drive circuit 116, converts the light amount of each pixel of the object image into an electrical signal, and outputs the electric signal to the CDS / ADC unit 124.

  The CDS / ADC unit 124 amplifies the electric signal input from the CCD 149 and performs analog / digital conversion, and temporarily stores the raw video data (Bayer data, hereinafter referred to as RAW data) that has just been subjected to the amplification and digital conversion. This is a circuit for outputting to the storage memory 117.

  The temporary storage memory 117 is a buffer made of, for example, SDRAM or the like, and is a memory device that temporarily stores the RAW data output from the CDS / ADC unit 124. The image processing unit 118 reads out the RAW data stored in the temporary storage memory 117 or the RAW data stored in the storage medium unit 119, and performs various corrections including distortion correction based on the image quality parameter designated from the control unit 113. It is a circuit that performs image processing electrically.

  The recording medium unit 119 detachably mounts a card-type or stick-type recording medium made of, for example, a flash memory, and RAW data transferred from the temporary storage memory 117 to the card-type or stick-type flash memory. This is a control circuit of an apparatus for recording and holding image data processed by the image processing unit 118.

  The display unit 120 includes a liquid crystal display monitor, and is a circuit that displays an image, an operation menu, and the like on the liquid crystal display monitor. The setting information storage memory unit 121 stores a ROM unit in which various image quality parameters are stored in advance, and an image quality parameter selected by an input operation of the operation unit 112 among the image quality parameters read from the ROM unit. RAM section is provided. The setting information storage memory unit 121 is a circuit that controls input and output to these memories.

  In the digital camera 140 configured in this manner, the imaging optical system 141 has a sufficiently wide angle range and a compact configuration according to the present invention, and is bright, high-magnification, and imaging performance in the entire magnification range. Is extremely stable, so high performance, downsizing, and wide angle of view can be realized.

  As described above, the image pickup apparatus including the optical path reflection type zoom lens according to the present invention is capable of simultaneously ensuring a wide angle of view, ensuring a high zoom ratio, ensuring brightness, and maintaining optical performance. Useful.

G1 ... 1st lens group G2 ... 2nd lens group G3 ... 3rd lens group G4 ... 4th lens group G5 ... 5th lens group G6 ... 6th lens group S ... Aperture stop F ... Low pass filter C ... Cover glass P ... Prism I ... Image plane 112 ... Operation unit 113 ... Control unit 114 ... Bus 115 ... Bus 116 ... Imaging drive circuit 117 ... Temporary storage memory 118 ... Image processing unit 119 ... Storage medium unit 120 ... Display unit 121 ... Setting information storage memory unit 122 ... Bus 124 ... CDS / ADC section 140 ... Digital camera 141 ... Shooting optical system 142 ... Shooting optical path 143 ... Viewfinder optical system 144 ... Viewfinder optical path 145 ... Shutter button 146 ... Flash 147 ... Liquid crystal display monitor 149 ... CCD
150 ... Cover member 151 ... Processing means 152 ... Recording means

Claims (26)

In order from the object side to the image side, a first positive lens group having positive refractive power, a first negative lens group having negative refractive power, and a rear lens group group having positive refractive power at the wide-angle end ,
The rear lens group includes a second positive lens group having positive refractive power, a second negative lens group disposed on the image side with respect to the second positive lens group, and an image side with respect to the second negative lens group. Having a third positive lens group,
Furthermore, it has an aperture stop disposed between the first negative lens group and the second negative lens group,
When zooming from the wide-angle end to the telephoto end,
The distance from the first positive lens group to the first negative lens group increases;
The distance from the first negative lens group to the second positive lens group decreases,
The distance from the second positive lens group to the second negative lens group changes;
The distance from the second negative lens group to the third positive lens group changes;
The first positive lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first positive lens group is 2,
The first negative lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first negative lens group is 2, and all the lens subgroups in the first negative lens group are single lenses,
The zoom lens characterized in that the first negative lens group satisfies the following conditional expression (1).
0.20 ≦ D2b / Hw ≦ 0.9 (1)
However,
D2b is a distance on the optical axis from the image side surface of the negative lens subgroup having the negative refractive power in the first negative lens group to the object side surface of the positive lens subgroup having the positive refractive power;
Hw is defined as Hw = fw · tan (ωw),
fw is the focal length of the entire zoom lens system at the wide-angle end,
ωw is a half angle of view with respect to the optical axis when a light beam that passes through the center of the aperture stop at the wide-angle end and enters the maximum image height position of the effective imaging region enters the zoom lens,
It is. In order from the object side to the image side, a first positive lens group having positive refractive power, a first negative lens group having negative refractive power, and a rear lens group group having positive refractive power at the wide-angle end ,
The rear lens group includes a second positive lens group having positive refractive power, a second negative lens group disposed on the image side with respect to the second positive lens group, and an image side with respect to the second negative lens group. Having a third positive lens group,
And an aperture stop disposed between the first negative lens group and the second positive lens group,
When zooming from the wide-angle end to the telephoto end,
The distance from the first positive lens group to the first negative lens group increases;
The distance from the first negative lens group to the second positive lens group decreases,
The distance from the second positive lens group to the second negative lens group changes;
The distance from the second negative lens group to the third positive lens group changes;
The first positive lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first positive lens group is 2,
The first negative lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first negative lens group is 2, and all the lens subgroups in the first negative lens group are single lenses,
The second positive lens group includes a positive lens subgroup and a second lens subgroup having positive refractive power,
Each of the positive lens subgroup and the second lens subgroup in the second positive lens group is composed of one lens component,
The distance on the optical axis from the aperture stop to the second positive lens group extends at the wide-angle end with respect to the telephoto end,
The zoom lens characterized in that the first positive lens group satisfies the following conditional expression (2).
3.1 ≦ fP1 / Hw ≦ 5.8 (2)
However,
fP1 is a focal length of the first positive lens group,
Hw is defined as Hw = fw · tan (ωw),
fw is the focal length of the entire zoom lens system at the wide-angle end,
ωw is a half angle of view with respect to the optical axis when a light beam that passes through the center of the aperture stop at the wide-angle end and enters the maximum image height position of the effective imaging region enters the zoom lens,
It is.
Here, the lens component is defined as a lens block in which only two surfaces of the object side surface and the image side surface are in contact with air on the effective surface. In order from the object side to the image side, a first positive lens group having positive refractive power, a first negative lens group having negative refractive power, and a rear lens group group having positive refractive power at the wide-angle end ,
The rear lens group includes a second positive lens group having positive refractive power, a second negative lens group disposed on the image side with respect to the second positive lens group, and an image side with respect to the second negative lens group. Having a third positive lens group,
The first negative lens group and the second positive lens group are arranged without any other lens group in between,
And an aperture stop disposed between the first negative lens group and the second positive lens group,
When zooming from the wide-angle end to the telephoto end,
The distance from the first positive lens group to the first negative lens group increases;
The distance from the first negative lens group to the second positive lens group decreases,
The distance from the second positive lens group to the second negative lens group changes;
The distance from the second negative lens group to the third positive lens group changes;
The first positive lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first positive lens group is 2,
The first negative lens group includes a negative lens subgroup having a negative refractive power, and a positive lens subgroup having a positive refractive power disposed on the image side of the negative lens subgroup having the negative refractive power, and The total number of lens subgroups in the first negative lens group is 2, and all the lens subgroups in the first negative lens group are single lenses,
The second positive lens group includes a positive lens subgroup and a second lens subgroup having positive refractive power,
Each of the positive lens subgroup and the second lens subgroup in the second positive lens group is composed of one lens component,
The zoom lens according to claim 1, wherein a distance on the optical axis from the aperture stop to the second positive lens group is widened at a wide angle end with respect to a telephoto end.
Here, the lens component is defined as a lens block in which only two surfaces of the object side surface and the image side surface are in contact with air on the effective surface. The first positive lens group has a reflecting member,
The reflective member is disposed between the negative lens subgroup and the positive lens subgroup of the first positive lens group, according to any one of claims 1 to 3. Zoom lens. The zoom lens according to any one of claims 1 to 3, wherein the first lens group is fixed with respect to an imaging position during zooming. 3. The zoom lens according to claim 1, wherein the first negative lens group and the second positive lens group are arranged without interposing another lens group therebetween. 2. The zoom lens according to claim 1, wherein the aperture stop is disposed between the first negative lens group and the second positive lens group. 2. The zoom lens according to claim 1, wherein a distance on the optical axis from the brightness stop to the second positive lens group is widened at a wide angle end with respect to a telephoto end. 9. The zoom lens according to claim 1, wherein the aperture stop is fixed with respect to an imaging position during zooming. 10. The zoom lens according to claim 1, wherein each of the negative lens sub group and the positive lens sub group in the first positive lens group includes one lens component. 11. The zoom lens according to claim 1, wherein the negative lens subgroup and the positive lens subgroup in the first positive lens group are single lenses. The second positive lens group includes a positive lens subgroup having positive refractive power and a second lens subgroup disposed closer to the image side than the positive lens subgroup having positive refractive power,
The second lens subgroup has a refractive power absolute value smaller than the refractive power absolute value of the positive lens subgroup in the second positive lens group, and
The zoom lens according to any one of claims 1 to 11, wherein the total number of lens subgroups in the second positive lens group is two. The zoom lens according to claim 12, wherein the second lens subgroup in the second positive lens group is a negative lens subgroup having a negative refractive power. 14. The zoom lens according to claim 12, wherein each of the positive lens sub group and the second lens sub group in the second positive lens group is one lens component.
Here, the lens component is defined as a lens block in which only two surfaces of the object side surface and the image side surface are in contact with air on the effective surface. At least one of the lenses in the first positive lens group and the first negative lens group is a lens having a low first specific gravity that satisfies the following conditional expression (6):
At least one of the lenses in the first positive lens group, the first negative lens group, the second positive lens group, and the second negative lens group has a refractive power of a lens having a small first specific gravity. 4. The lens according to claim 1, wherein the lens has a refractive power with a sign different from that of the first lens and satisfies the following conditional expression (6). Zoom lens.
0.9g / cm ³ ≦ SG ≦ 2.0 g / cm ³             (6)
However,
SG is the specific gravity of each of the first low specific gravity lens and the second low specific gravity lens,
It is. The zoom lens according to claim 15, wherein the first low specific gravity lens and the second low specific gravity lens satisfy the following conditional expression (7).
1.45 ≦ ndPL ≦ 1.8 (7)
However,
ndPL is a refractive index with respect to d-line of the first low specific gravity lens and the second low specific gravity lens;
It is. The zoom lens according to claim 16, wherein the second low specific gravity lens is included in either the first positive lens group or the first negative lens group. 18. The zoom lens according to claim 1, wherein the second negative lens group moves to the image side during focusing from a long-distance object to a short-distance object. The zoom lens according to any one of claims 1 to 18, wherein the second negative lens group satisfies the following conditional expression (3).
2.0 ≦ | fN2 / Ht | ≦ 4.5 (3)
However,
fN2 is a focal length of the second negative lens group,
Ht is defined by Ht = ft · tan (ωt),
ft is the focal length of the entire zoom lens system at the telephoto end,
ωt is a half angle of view with respect to the optical axis when a light beam that passes through the center of the aperture stop at the telephoto end and enters the maximum image height position of the effective imaging region enters the zoom lens,
It is. The zoom lens according to any one of claims 1 to 18, wherein the second negative lens group satisfies the following conditional expression (4).
0.3 ≦ | fN2 / ft | ≦ 0.7 (4)
However,
fN2 is a focal length of the second negative lens group,
ft is the focal length of the entire zoom lens system at the telephoto end,
It is. The zoom lens according to claim 2 or 3, wherein the first negative lens group satisfies the following conditional expression (1).
0.20 ≦ D2b / Hw ≦ 0.9 (1)
However,
D2b is a distance on the optical axis from the image side surface of the negative lens subgroup having the negative refractive power in the first negative lens group to the object side surface of the positive lens subgroup having the positive refractive power;
Hw is defined as Hw = fw · tan (ωw),
fw is the focal length of the entire zoom lens system at the wide-angle end,
ωw is a half angle of view with respect to the optical axis when a light beam that passes through the center of the aperture stop at the wide-angle end and enters the maximum image height position of the effective imaging region enters the zoom lens,
It is. The zoom lens according to any one of claims 1 to 21, wherein the first positive lens group satisfies the following conditional expression (5).
0.2 ≦ D1b / fP1 ≦ 0.6 (5)
However,
D1b is an air equivalent distance along the optical axis from the image side surface of the negative lens sub-group having negative refractive power in the first positive lens unit to the object side surface of the positive lens sub-group having positive refractive power;
fP1 is a focal length of the first positive lens group,
It is. The zoom lens according to any one of claims 1 to 22, wherein all the lens subgroups in the first positive lens group are single lenses. The lens surface on the most object side of the negative lens subgroup in the first positive lens group is a lens surface that is concave on the object side, 24. Zoom lens. The zoom lens according to any one of claims 1 to 24, wherein the first negative lens group satisfies the following conditional expression (8).
0.45 ≦ | fN1n | × fN1p / fN1 ² ≦ 1.8 (8)
However,
fN1n is the focal length of the negative lens subgroup in the first negative lens group,
fN1p is the focal length of the positive lens subgroup in the first negative lens group,
fN1 is a focal length of the first negative lens group,
It is. An image pickup apparatus comprising: the zoom lens according to any one of claims 1 to 25; and an image pickup element disposed on an image side of the zoom lens.

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