JP3226297B2 - Zoom lens and camera with zoom lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications] Wide-angle zoom lenses and wide-angle
The present invention relates to a camera having a zoom lens .

[0002]

2. Description of the Related Art In a conventional so-called negative-leading type wide-angle zoom lens, when zooming is performed, the total length of the lens system changes, and a heavy first lens unit having a negative refractive power moves nonlinearly and moves. However, there are disadvantages such as a large amount, a long overall length at the wide-angle end, a reduction in smoothness due to a change in the driving amount during zooming movement, and a change in the weight balance.

On the other hand, making the zoom lens waterproof or drip-proof has a great significance in expanding the use of the camera and making it possible to take a picture in bad weather. In addition, when the first lens group is moved by zooming, it is preferable that the first lens group is protected so as not to damage the lens surface without being noticed, and can be used freely in an expanded environment.

[0004] However, the conventional total length variable zoom lens,
It is difficult to form a so-called hermetic structure, and it is difficult to realize even by using a packing such as an O-ring.

A negative-leading afocal zoom lens for a television camera or a cine camera having a constant overall length, which has been conventionally employed for a wide-angle system, is a lens system having a long overall length and a large front group, which is used for a steel camera. Is inappropriate.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a zoom lens for a still camera, wherein the overall length thereof is substantially constant so that the lens system can have a sealed structure. It is another object of the present invention to provide a lens system having a relatively large zoom ratio, which can be sufficiently applied, and a camera having the same.

[0007]

A zoom lens according to the present invention comprises, in order from the object side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a negative refractive power. And a fourth lens group having a positive or negative refractive power, and a fifth lens group having a positive refractive power. The first lens group and the fifth lens group are substantially fixed with respect to the image plane. By moving the second lens group, the third lens group, and the fourth lens group, the magnification and the image plane position are made substantially constant, and the following conditions are satisfied. (1) 0.5 <| φ12w / φw | <4.0 (2) 0.05 <| φ34w / φw | <1.5 (3) β3w ・ β4w <β3T ・ β4T where φ12w is the first at the wide angle end The combined refractive power of the lens group and the second lens group, φ34w is the combined refractive power of the third and fourth lens groups at the wide-angle end, φw is the refractive power of the entire system at the wide-angle end, and β3w is the wide-angle end. , Β4w is the paraxial magnification of the fourth lens group at the wide-angle end, β3T is the paraxial magnification of the third lens group at the telephoto end, and β4T is the paraxial magnification of the fourth lens group at the telephoto end. Magnification.

As described above, the lens system of the present invention employs a zooming system in which a change in the total length during zooming operation is small and a mechanism of a waterproof or drip-proof structure can be realized.

As a conventional wide-angle zoom lens for a still camera, a lens system as shown in FIGS. 37 and 38 is generally used. In the drawing, W, S, and T represent a wide angle end, an intermediate focal length, and a telephoto end, respectively. However, there is no zoom lens having a constant overall length during zooming, which is a lens system including a wide-angle region, which is the object of the present invention.

The reason for this is that a so-called standard zoom lens having a zoom ratio of 2 or less as shown in FIG. 37 is a two-unit zoom lens which is almost negative leading or a two-unit zoom lens to which a field flatner is added as a third lens unit. Is an extension of. When the zoom ratio is further increased, as shown in FIG. 38 , a four-unit zoom lens is obtained by double-zooming the two-unit zoom lens. However, each of these changes the overall length of the lens system. Therefore, while covering the wide angle of view, the first surface of the lens system to the film surface is almost constant during zooming, the change in volume of the medium (air) in the lens barrel is small, and the driving torque during zooming is small. It is necessary to develop a zoom lens that does not matter.

Further, assuming that the wide-angle zoom lens is for a single-lens reflex camera, a retrofocus type in which a negative first lens group and a positive second lens group are arranged in this order from the object side allows the mirror to be arranged. The power arrangement can secure the space to be used.

On the other hand, in this two-unit zoom lens, when zooming is performed by the second lens unit, the image plane position must be necessarily corrected by the first lens unit. The group must be moved. Therefore , one of the objects of the present invention described above is not achieved.

At the wide-angle end, the lens system of the present invention comprises a plurality of lens groups, the first lens group is fixed during zooming, the second lens group, the third lens group, and the second lens group. At least four lens groups, and any one of the second to fourth lens groups has a function of a variable power system and a compensator . Further, a fifth lens group fixed to the image plane is provided as a final lens group as needed.

Also, from the viewpoint of aberration correction, one lens group is divided into two parts, and the magnification is shared between the two lens groups, thereby reducing the burden on the magnification and increasing the degree of freedom in aberration correction.

Further, all of the second to fourth lens units are made movable at the time of zooming so that the zoom ratio becomes about 3 or more.

As described above, the present invention provides the above-described configuration.
And the conditions (1), (2) and (3) were satisfied.

As described above, the zoom lens according to the present invention has a particularly strong retrofocus type characteristic in a wide-angle range and can take a sufficient back focus.

The movement of each lens unit during zooming of the lens system of the present invention is as shown in FIGS. 29, 30 and 31, and the movement amounts of the second lens unit and the fourth lens unit are large.
The third lens group is suitable for a role as a compensator for keeping the image plane position constant. Regarding the movement of each lens group during zooming, from the wide-angle end to the telephoto end,
The distance between the first lens group and the second lens group is reduced, the distance between the second lens group and the third lens group is increased, and the distance between the third lens group and the fourth lens group is reduced. Moving. Further, in a general two-unit zoom lens, when the magnification of the rear unit is equal to or less than the same magnification, the overall length of the lens system becomes the longest at the wide angle end. On the other hand, the zoom lens of the present invention has one major feature that the overall length is shorter as a whole in the variable power range. The reason for this is that the total length on the telephoto side becomes longer and the telephoto ratio can be increased, so that the burden on aberration correction such as spherical aberration correction on the telephoto side, which is a problem with this type of lens system, is reduced. . Conversely, at the wide-angle end,
Since the total length tends to be shortened, and the entrance pupil distance is also shortened, as a result, it is easy to secure the peripheral light amount, which is advantageous in realizing an ultra wide angle.

Next, the above conditions will be described.

Conditions (1), (1-1), (1-2),
( 2) is a condition that defines the refractive power of the first to fourth lens groups. The conditions (1), (1-
1) and (1-2) are conditions that define the combined refractive power of the first lens unit and the second lens unit at the wide-angle end. If the lower limit is exceeded, it is advantageous for aberration correction but the overall length is long. It is not desirable. On the other hand, exceeding the upper limit is not preferable for aberration correction. In particular, the first lens group is important for correcting distortion, and has a large effect on aberration correction at the wide-angle end. In order to increase the resolving power, attention must be paid to chromatic aberration of magnification.
In order to correct spherical aberration and coma aberration, the second lens unit having a high ray height is important, and it is necessary to adjust the refractive power of the first lens unit and the second lens unit to an appropriate value on the balance of chromatic aberration. is important.

Next, the condition (2) defines the combined refractive power of the third lens unit and the fourth lens unit. Exceeding the lower limit of condition (2) is not preferable because the zooming movement amount becomes large. When the value exceeds the upper limit of the condition (2), the lens group of interest is an image forming system, and it becomes difficult to correct aberrations particularly regarding image plane correction.

Next, in the present invention, it is effective to dispose the fifth lens group as a fixed group, and the effect is a field flattener for correcting the field curvature more than as a relay system. The focal length of the lens system at the wide-angle end is
Considering the gist of the present invention, it is generally shorter than the diagonal length of the camera screen. That is, it is general that the following relationship is satisfied. (4) fw <D where fw is the focal length of the entire lens system, and D is the screen diagonal length.

Next, the image forming relationship in the lens system of the present invention will be described. It depends on the refractive power and movement of each lens group. What is common here is that the magnification of the second lens group increases from the wide-angle end to the telephoto end. Therefore, this second lens group is suitable for use as a lead cam.

The magnification products β3 and β4 of the magnifications of the third lens unit and the fourth lens unit are in a multiplication relation. In other words, the front group
It can be seen that the first lens group and the second lens group are in a multiplication relation, and the third lens group and the fourth lens group are in a multiplication relation.

Further, the lens system of the present invention has the following features with respect to aberration correction.

One of the features of the lens system of the present invention is that the aperture stop is arranged in the third lens group and that the lens system is of a negative leading type.

Changes in various aberrations during zooming are relatively large in the first lens unit and the second lens unit, and are relatively small in the third and subsequent lens units. This depends on the type of zooming, and does not necessarily depend on the specifications of the lens system. This is because, assuming that the aperture stop is arranged in the third lens group, the influence of the off-axis ray having a high ray height tends to be large in the first lens group far from the entrance pupil position, and this portion is changed. This is because the passing state of the luminous flux changes at the time of doubling. This is remarkable at the wide-angle end where the angle of view is large. In particular, distortion tends to be negatively displaced. Therefore, the lens configuration in this part is important,
It is necessary to reduce residual aberration in this part as much as possible.

On the other hand, since the lens system of the present invention is of the negative leading type, the axial rays incident on the second lens group are high, so that the second lens mainly reduces spherical aberration, coma and axial chromatic aberration. The influence of the group is great. Therefore, one of the features is the restriction on the aperture ratio on the telephoto side.

In the lens system of the present invention, the total length in the entire focal range is substantially constant. Therefore, the total length at the wide-angle end is smaller than that of the lens system in which the first lens unit is movable due to the condition (1). , On the telephoto side, on the contrary, it tends to be longer than the zoom lens movable in the first lens group. This is a characteristic difference from the conventional zoom type. That is, in a telephoto range where a telephoto ratio can be obtained, it is advantageous for aberration correction.

Further, although the amount of movement of each group depends on the zoom ratio, the second lens group always has the characteristic of multiplying, and in the present invention, the magnification of the combination of the third lens unit and the fourth lens unit. β3 ・ β
4 is also configured to multiply. Condition (3) shows this by a conditional expression. However, it is convenient for the third lens group to have the function of making the image plane constant in addition to the functions of zooming and aberration correction.

In this lens group, the movement becomes non-linear in the telephoto range and may have an inflection point.

The relation of the magnification of the second lens group is represented by the following conditional expression. β2w <β2T The relationship of movement is as follows. FIG. 36 shows the relationship between the movement amounts of the second, third, and fourth lens units during zooming. The movement amounts x2, x3, x4 of each embodiment will be described later.

In the lens system according to the present invention, the ratio x2 / x4 of the movement amount x2 of the second lens unit to the movement amount x4 of the fourth lens unit is within the following range. 0.7 <x2 / x4 <10.0 If the lower limit of the condition is exceeded, the relative movement amount of the second lens unit decreases, so that it is difficult to increase the zoom ratio, and the third lens unit and the fourth lens unit This is not desirable because the magnification burden on is increased. If the value exceeds the upper limit, the amount of movement of the second lens unit increases, and aberration fluctuation during zooming increases.

Next, the configuration of each lens group in the lens system of the present invention will be described.

Since the first lens group having negative refractive power has a relatively long entrance pupil distance at the wide-angle end, it is preferable to arrange the negative lens component at the head to reduce the incident angle. Of course, it is conceivable to put a positive lens component forward in order to correct the distortion, but this is not preferable because the outer diameter becomes large. Therefore, it is preferable to arrange the lenses like a negative lens and a positive lens component to balance aberrations. In this case, it is preferable to use an aspherical surface at the wide-angle end because a large amount of negative distortion occurs at the wide-angle end, and this makes it possible to achieve a super-wide-angle lens system.

The entrance pupil is generally long at the wide-angle end, but in order to provide a refractive power arrangement such that the total length of the lens system is constant from the wide-angle end to the telephoto end, the entrance pupil is shorter at the wide-angle end and shorter at the telephoto end. It differs from conventional zoom lenses in that it is longer. As a result, there is an advantage that the incident position is relatively short, the filter diameter is small, and the front lens diameter is also small. However, since the position of the entrance pupil becomes longer at the telephoto end, there is no problem that the angle of view becomes narrower.

Next, the second lens group plays a large role in correcting, in particular, spherical aberration and coma. This is because the relative aperture ratio becomes large in this lens group. Further, it is important to correct axial chromatic aberration to improve the center contrast and resolution. From the above, it is usually necessary to combine a doublet in which a positive lens and a negative lens are bonded together with a positive lens, but it is effective to use a triplet lens.

The third lens unit has a positive lens component and a negative lens component, has a function as a compensator, and is in a floating relationship with the fourth lens unit.

The fourth lens group includes a positive lens component and a negative lens component, and has an image forming action in addition to zooming.

Further, the fifth lens unit is composed of a positive lens component that finely corrects residual aberration from the first lens unit to the fourth lens unit, particularly, residual curvature of field.

[0041]

Next, embodiments of the zoom lens according to the present invention will be described. Example 1 f = 21.7-49.1, F / 4.5-F / 5.8, 2ω = 89.7 ° -47.5 ° r1 = 170.9797 d1 = 1.1000 n1 = 1.83481 ν1 = 42.72 r2 = 26.4545 (aspherical surface) d2 = 4.3702 r3 = 137.3708 d3 = 3.2516 n2 = 1.84666 ν2 = 23.78 r4 = -216.0576 d4 = 0.1200 r5 = -375.6913 d5 = 1.1000 n3 = 1.69680 ν3 = 55.52 r6 = 20.8564 (aspherical surface) d6 = 3.0928 r7 = 41.81 ν = 32.7988 ν r8 = 24.5952 d8 = 0.1500 r9 = 25.0765 d9 = 6.4614 n5 = 1.64769 ν5 = 33.80 r10 = 4915.9863 d10 = D1 (variable) r11 = 68.2574 d11 = 1.4583 n6 = 1.80400 ν6 = 46.0.11312 = 46.0.11312 3.6724 n7 = 1.84666 v7 = 23.88 r14 = 23.5782 d14 = 3.3820 n8 = 1.69690 v8 = 56.49 r15 = 250.1688 d15 = 0.1000 r16 = 24.6446 d16 = 3.9206 n9 = 1.61700 v9 = 62.79 r17 = -103.4564 (Aperture) d18 = 1.0000 r19 = -228.5059 d19 = 1.6067 n10 1.84666 v10 = 23.88 r20 = -29.6935 d20 = 1.3807 n11 = 1.50378 v11 = 66.81 r21 = -20.6660 d21 = 0.2447 r22 = -18.8590 d22 = 1.1000 n12 = 1.74320 v12 = 49.31 r23 = 26.0834 d23 = D876 d24 = 3.1619 n13 = 1.60300 v13 = 65.48 r25 = -23.5483 d25 = 0.1000 r26 = 1970.0412 d26 = 5.2686 n14 = 1.49700 v14 = 81.61 r27 =-16.9041 d27 = 0.1670 r28 = -16.8370 d28 = 1.1000 n15 = 1.83400 -51.9298 d29 = D4 (variable) r30 = -92.3954 d30 = 3.2285 n16 = 1.61700 ν16 = 62.79 r31 = -38.2959 Aspherical surface coefficient (second surface) P = 1.0000, E = −0.17510 × 10 ^-4 , F = −0.1
3193 × 10 ^-7 G = 0.56055 × 10 ^-10 , H = -0.77772 × 10 ^-13 (Sixth surface) P = 1.0000, E = 0.81144 × 10 ^-5 , F = -0.2
2960 × 10 ^-9 G = -0.12606 × 10 ^-9 , H = 0.91554 × 10 ^-13 f 21.7 32.8 49.1 D1 24.295 10.044 1.553 D2 1.700 5.823 12.218 D3 9.348 9.115 2.870 D4 0.880 11.241 19.580 φ12w / φw = 1.261, φ34w / φw = -0.1957, β2w =-
0.5723, β2T = -1.1200 β3wβ4w = 1.944446, β3Tβ4T = 4.0916, x2 / x4 = 1.
216 Example 2 f = 24.3-77.7, F / 4.6-F / 5.8, 2ω = 83.3 ° -31.1 ° r1 = 107.2744 d1 = 1.0000 n1 = 1.83400 ν1 = 37.16 r2 = 33.0005 d2 = 6.0916 r3 = 391.8495 d3 = 4.0680 n2 = 1.68893 v2 = 31.08 r4 = -78.8483 d4 = 0.1200 r5 = 328.1877 d5 = 1.0000 n3 = 1.83481 v3 = 42.72 r6 = 39.0346 d6 = 2.4526 r7 = 88.1390 d7 = 1.38 n4 = 1.49 n4 = 1.49 700 1.84666 ν5 = 23.78 r9 = 32.4661 d9 = D1 (variable) r10 = 40.1886 d10 = 2.3684 n6 = 1.49700 ν6 = 81.61 r11 = 71.8883 d11 = 0.1200 r12 = 42.8479 d12 = 3.1911 n7 = 1.84666 88713 = 1.69680 v8 = 55.52 r14 = -188.0267 d14 = 0.1200 r15 = 24.9476 d15 = 3.2335 n9 = 1.69680 v9 = 55.52 r16 = 2564.0158 d16 = D2 (variable) r17 = ∞ (aperture) d17 = 0.6147 r18 = -147.5174 d18 = 812 = 1.84666 v10 = 23.88 r19 = -18.8152 d19 = 1.000 n11 1.83481 ν11 = 42.72 r20 = 77.2279 d20 = 0.5264 r21 = -68.8248 d21 = 1.0000 n12 = 1.69680 ν12 = 55.52 r22 = 27.0982 d22 = D3 (variable) r23 = 752.3348 d23 = 3.7442 n13 = 1.56907 d24 = 71.30 r24 0.1200 r25 = 55.3467 d25 = 5.2307 n14 = 1.49700 v14 = 81.61 r26 = -19.2854 d26 = 1.0000 n15 = 1.83400 v15 = 37.16 r27 = −378.8459 d27 = D4 (variable) r28 = 1657.0512 d28 = 2.7117 n16 = 42.8427216 -97.0075 f 24.3 43.6 77.7 D1 30.533 12.899 2.000 D2 2.000 5.433 12.592 D3 10.768 7.588 1.344 D4 1.150 18.531 28.514 φ12w / φw = 1.800, φ34w / φw = -0.4140, β2w =-
0.4388, β2T = -1.0160 β3wβ4w = 2.8178, β3Tβ4T = 3.2700, x2 / x4 = 1.04
1 Example 3 f = 40.2-59.8, F / 2.2-F / 2.1, 2ω = 56.6 ° -39.7 ° r1 = 4687.3004 d1 = 1.0659 n1 = 1.83400 ν1 = 37.16 r2 = 45.8358 d2 = 3.8079 r3 = 229.7202 d3 = 1.6132 n = 1.59551 ν2 = 39.21 r4 = 83.4386 d4 = 0.5371 r5 = 52.4821 d5 = 4.6611 n3 = 1.84666 ν3 = 23.78 r6 = 501.6307 d6 = 2.9855 r7 = -74.9661 d7 = 1.1233 n4 = 1.53.14 = 1.53.44 = 1.53.11 = 4. 1.74000 v5 = 28.29 r9 = 165.9146 d9 = D1 (variable) r10 = 141.5455 d10 = 5.1678 n6 = 1.80610 v6 = 40.95 r11 = -73.4960 d11 = 0.6914 r12 = 65.2771 d12 = 1.5768 n7 = 1.83400 v7667 n8 = 1.69680 v8 = 55.52 r14 = -43.8874 d14 = 1.7200 n9 = 1.84666 v9 = 23.78 r15 = -615.6574 d1 = D2 (variable) r16 = ∞ (aperture) d16 = 4.1118 r17 = 93.4452 d17 = 2.4287 n10 = 1.81518 r18 = 47.9971 d18 = 1.4966 r19 = 30.8331 d19 = 3.4154 n11 = 1.53172 ν11 = 48.90 r20 = 99.3872 d20 = 2.4598 r21 = −39.9044 d21 = 1.4714 n12 = 1.60311 ν12 = 60.70 r22 = 23.8495 d22 = 3.3323 n13 = 1.84666 ν13 = 23.78 r23 = 54.7600 d23 = 24 = 132 = 32 = 24 1.3122 n14 = 1.80518 v14 = 25.43 r25 = 54.6188 d25 = 0.5381 r26 = 96.7077 d26 = 1.2188 n15 = 1.84666 v15 = 23.78 r27 = 44.4318 d27 = 6.9330 n16 = 1.62280 v16 = 57.06 r28 = 5.940 d29 = 6400 n17 = 1.80610 v17 = 40.95 r30 = -2091.2177 f 40.2 50.1 59.8 D1 17.698 8.738 2.261 D2 2.031 10.660 17.707 D3 7.034 5.254 2.087 φ12w / φw = 0.7229, φ34w / φw = 0.482, β2w = -1.0
300, β2T = -1.675 β3wβ4w = 0.7289, β3Tβ4T = 23.5560, x2 / x4 = 3.
Example 4 f = 40.1 to 59.9, F / 2.2 to F / 2.2, 2ω = 56.7 ° to 39.7 ° r1 = 7066.1589 d1 = 1.1762 n1 = 1.83400 ν1 = 37.16 r2 = 45.3679 d2 = 3.8512 r3 = 234.2121 d3 = 1.6140 n2 = 1.59551 v2 = 39.21 r4 = 81.1349 d4 = 0.4993 r5 = 53.0793 d5 = 4.66837 n3 = 1.84666 v3 = 23.78 r6 = 563.0834 d6 = 2.4928 r7 = -95.0232 d7 = 11.5 n8 = 4.1.5 n8 = 1. 1.74000 v5 = 28.29 r9 = 134.4132 d9 = D1 (variable) r10 = 105.7047 d10 = 5.2659 n6 = 1.80610 v6 = 40.95 r11 = -82.9131 d11 = 0.7038 r12 = 57.6589 d12 = 1.5955 n7 = 1.83400 ν = 1.83400 ν n8 = 1.69968 v8 = 55.52 r14 = -48.9894 d14 = 1.8041 n9 = 1.84666 v9 = 23.78 r15 = -3333.4457 d15 = D2 (variable) r16 = ∞ (aperture) d16 = 4.1772 r17 = 101.5239 d17 = 2.5241 n10 = 1.81518 r18 = 45.9697 d18 = 1.6219 r19 = 34.5520 d19 = 3.5052 n 11 = 1.53172 v11 = 48.90 r20 = 124.3129 d20 = 2.4994 r21 = -38.4675 d21 = 1.5667 n12 = 1.60311 v12 = 60.70 r22 = 23.5327 d22 = 3.4095 n13 = 1.84666 v13 = 23.78 r23 = 61.0593 d23 = 24 = variable d24 = 1.3495 n14 = 1.80518 v14 = 25.43 r25 = 53.4891 d25 = 0.6071 r26 = 97.8294 d26 = 1.2996 n15 = 1.84666 v15 = 23.78 r27 = 41.4667 d27 = 7.0261 n16 = 1.62280 v16 = 57.06 r28 = -0.302024 = 6.1001 n17 = 1.80610 v17 = 40.95 r30 = 312.7578 f 40.1 50.0 59.9 D1 16.965 8.963 2.491 D2 1.497 10.800 18.152 D3 6.706 5.430 2.192 φ12w / φw = 0.803, φ34w / φw = 0.4819, β2w = -0.9
557, β2T = -1.493 β3wβ4w = 0.80469, β3Tβ4T = 20.6452, x2 / x4 =
5.8460 Example 5 f = 36.0-101.6, F / 4.6-F / 5.8, 2ω = 61.9 ° -24.0 ° r1 = -72.1560 d1 = 1.2000 n1 = 1.80610 ν1 = 40.95 r2 = 142.0500 d2 = 1.8600 r3 = -161.6170 d3 = 3.1600 n2 = 1.84666 v2 = 23.78 r4 = -52.7310 d4 = 3.1400 r5 = -735.4740 d5 = 0.7800 n3 = 1.80610 v3 = 40.95 r6 = 40.8510 d6 = 0.1200 r7 = 37.7440 d7 = 4 1.84 n6 = 2.2510 n4 0.8000 r9 = 54.3910 d9 = 0.8800 n5 = 1.51633 ν5 = 64.15 r10 = 43.9360 d10 = 1.2500 n6 = 1.64769 ν6 = 33.80 r11 = 36.5870 d11 = D1 (variable) r12 = 38.2360 d12 = 13400 n7 1.83 = 6.0000 n8 = 1.69680 v8 = 55.52 r14 = -76.7960 d14 = 0.9000 n9 = 1.84666 v9 = 23.78 r15 = -1067.7000 d15 = 0.1500 r16 = 60.2260 d16 = 2.3900 n10 = 1.65830 v10 = 57.33 r17 = -26.860 d18 = 2.8900 n11 = 1.49700 v11 = 81.61 r19 = 56.3070 d19 D2 (variable) r20 = ∞ (aperture) d20 = 1.5840 r21 = -55.9820 d21 = 1.0600 n12 = 1.51821 ν12 = 65.04 r22 = -108.3330 d22 = 4.2690 r23 = 28.9520 d23 = 0.7800 n13 = 1.50378 v13 = 66.81 r24 = 12.6150 d24 2.0000 n14 = 1.56883 v14 = 56.34 r25 = 14.1830 d25 = D3 (variable) r26 = -28.0240 d26 = 1.6230 n15 = 1.50378 v15 = 66.81 r27 = -18.3400 d27 = 0.1500 r28 = -31.5140 d28 = 4.1950 n16 = 1.52384 v29 = 50.50 = -10.7388 d29 = 0.1000 r30 = -10.6600 d30 = 0.8000 n17 = 1.83400 ν17 = 37.16 r31 = -26.1720 d31 = D4 (variable) r32 = -22.8800 d32 = 2.4780 n18 = 1.78470 ν18 = 26.22 r33 = -19.0510 f 36.0 65.7 101.6 D1 36.000 14.810 1.850 D2 2.600 7.560 18.810 D3 3.180 7.860 3.070 D4 1.700 13.370 19.670 φ12w / φw = 1.80, φ34w / φw = -0.900, β2w = -0.47
5, β2T = -1.143 β3wβ4w = 2.55662, β3Tβ4T = 2.9938, x2 / x4 = 1.
897 Example 6 f = 35.9 to 101.9, F / 4.6 to F / 5.8, 2ω = 68.5 ° to 24.0 ° r1 = 1541.6370 d1 = 1.1700 n1 = 1.80440 ν1 = 39.58 r2 = 46.0860 d2 = 0.1400 r3 = 48.1200 d3 = 2.2700 n2 = 1.84666 ν2 = 23.78 r4 = 78.3300 d4 = D1 (variable) r5 = -1570.2640 d5 = 0.9700 n3 = 1.77250 ν3 = 49.66 r6 = 45.6510 d6 = 0.1760 r7 = 44.0710 d7 = 1.84 n8 = 2.34 n4 = 4. 0.8500 r9 = 54.6500 d9 = 0.8900 n5 = 1.50378 ν5 = 66.81 r10 = 35.4040 d10 = 1.3100 n6 = 1.646446 ν6 = 35.81 r11 = 38.8660 d11 = D2 (variable) r12 = 57.0740 d12 = 13.500 n7 = 1.87 = 4.9950 n8 = 1.65830 v8 = 57.33 r14 = -40.7890 d14 = 0.8940 n9 = 1.84666 v9 = 23.78 r15 = -92.3040 d15 = 0.1440 r16 = 50.1200 d16 = 2.0000 n10 = 1.48749 d10 = 70.18 d17 = 181.1400 d17 = 181.1400 = 3.1750 n11 = 1.48749 ν11 = 70.20 r19 = -325.1830 19 = D3 (variable) r20 = ∞ (aperture) d20 = 3.5520 r21 = -12.8820 d21 = 1.1100 n12 = 1.59270 v12 = 35.29 r22 = -13.1830 d22 = 2.3870 r23 = -418.8670 d23 = 1.000 n13 = 1.74100 v13 = 52.68 r24 = 13.9560 d24 = 2.9600 n14 = 1.84666 v14 = 23.78 r25 = 19.7000 d25 = D4 (variable) r26 = 147.7420 d26 = 1.4440 n15 = 1.83400 v15 = 37.16 r27 = -123.2220 d27 = 0.2000 r28 = -68.8970 d28 = 4.1100 n16 = 1.4 81.61 r29 = -11.3250 d29 = 0.7950 n17 = 1.66680 v17 = 33.04 r30 = -30.0310 d30 = D5 (variable) r31 = -30.7810 d31 = 2.6800 n18 = 1.76200 n18 = 40.10 r32 = -22.7690 f 35.9 62.2 101.9 D1 3.930 6.600 2.910 33.960 12.480 1.500 D3 5.140 12.140 22.580 D4 4.860 5.600 1.100 D5 2.200 13.290 22.010 φ12w / φw = 1.724, φ34w / φw = -0.754, β2w = -0.5
00, β2T = -1.217 β3wβ4w = 2.63920, β3Tβ4T = 3.05895, x2 / x4 =
1.6919 Example 7 f = 31.7-101.4, F / 4.6-F / 5.8, 2ω = 62.1 ° -23.9 ° r1 = -134.5080 d1 = 0.9740 n1 = 1.80610 ν1 = 40.95 r2 = 86.1340 d2 = 2.0750 r3 = 1812.5700 d3 = 3.4380 n2 = 1.84666 v2 = 23.78 r4 = -82.1858 d4 = 2.7910 r5 = -2626.6621 d5 = 0.9109 n3 = 1.80610 v3 = 40.95 r6 = 37.5270 d6 = 0.1566 r7 = 33.7558 d7 = 1.84 n8 = 2.3717 n4 = 2.3717 n4 r9 = 87.6457 d9 = 0.9559 n5 = 1.51633 v5 = 64.15 r10 = 33.6919 d10 = 1.5749 n6 = 1.64769 v6 = 33.80 r11 = 36.0551 d11 = D1 (variable) r12 = 35.5343 d12 = 1.837 n7 = 1.83 n7 = 1.83 6.3337 n8 = 1.69680 v8 = 55.52 r14 = -72.4562 d14 = 0.7333 n9 = 1.84666 v9 = 23.78 r15 = -619.0383 d15 = 0.0680 r16 = 101.8110 d16 = 2.4937 n10 = 1.65830 v10 = 57.1818 r17 = -112.8208 304 = 2.9234 n11 = 1.49700 v11 = 81.61 r19 = 76.6686 d19 D2 (variable) r20 = ∞ (aperture) d20 = 1.5908 r21 = -62.8420 d21 = 1.130 n12 = 1.51821 v12 = 65.04 r22 = 194.9900 d22 = 4.3650 r23 = 33.6980 d23 = 0.6500 n13 = 1.50378 v13 = 66.81 r24 = 13.4870 d24 n14 = 1.56883 v14 = 56.34 r25 = 14.4940 d25 = D3 (variable) r26 = -37.6700 d26 = 1.8020 n15 = 1.50378 v15 = 66.81 r27 = -19.5170 d27 = 0.0133 r28 = -27.7950 d28 = 3.6130 n16 = 1.51742 v16 = 52.41 -10.6760 d29 = 0.5380 n17 = 1.83400 v17 = 37.16 r30 = -23.1830 d30 = D4 (variable) r31 = -24.3230 d31 = 2.5970 n18 = 1.78470 v18 = 26.22 r32 = -19.7000 f 31.7 61.6 101.4 D1 37.380 14.847 1.700 D2 2.346 D3 3.182 7.790 3.210 D4 0.709 13.147 19.904 φ12w / φw = 1.967, φ34w / φw = -0.9201, β2w = -0.439,
β2T = -1.1766 β3wβ4w = 2.86320, β3Tβ4T = 3.41543 x2 / x4 = 1.8572 Example 8 f = 36.2 to 131.0, F / 4.6 to F / 5.8, 2ω = 60.3 ° to 35.12
° r1 = -223.0764 (aspheric surface) d1 = 1.8500 n1 = 1.76182 ν1 = 26.55 r2 = -93.5144 d2 = 0.1200 r3 = -116.7127 d3 = 0.8500 n2 = 1.81554 ν2 = 44.36 r4 = 28.7056 d4 = 0.1200 r5 = 27.6554 d5 = 4.8500 n3 = 1.84666 ν3 = 23.88 r6 = 75.2765 d6 = 0.8340 r7 = 94.2680 d7 = 2.0000 n4 = 1.48749 ν4 = 70.20 r8 = -325.4895 d8 = 0.8000 n5 = 1.69680 ν5 = 55.52 r9 = 37.8726 d9 = D1 (variable) r10 = 38.779 ( (Aspheric surface) d10 = 1.0000 n6 = 1.85026 ν6 = 32.28 r11 = 19.8769 d11 = 6.2000 n7 = 1.69680 ν7 = 55.52 r12 = -74.0633 d12 = 0.5500 n8 = 1.84666 ν8 = 23.88 r13 = -358.8865 d13 = 0.1200 r14 = 37.0599 d14 = 3.5000 n9 = 1.49700 ν9 = 81.61 r15 = -226.1367 d15 = 0.1200 r16 = 35.5491 d16 = 3.0000 n10 = 1.49700 ν10 = 81.61 r17 = 153.6430 (aspherical surface) d17 = D2 (variable) r18 = ∞ (aperture) d18 = 2.0000 r19 = 341.9337 d19 = 1.9100 n11 = 1.53358 ν11 = 51.56 r20 = 20.0111 d20 = 3.7582 r21 = -20.8036 d21 = 0.6500 n12 = 1.51821 ν12 = 65.04 r22 = 21.9088 d22 = 2.1500 n13 = 1.72825 ν13 = 28.46 r23 = -298.0561 d23 = D3 ) r24 = -167.0599 d24 = 2.5000 n14 = 1.53113 ν14 = 62.44 r25 = -35.3445 d25 = 0.1000 r26 = -435.8022 d26 = 5.8500 n15 = 1 .48749 ν15 = 70.20 r27 = -14.4781 d27 = 0.1200 r28 = -14.4036 d28 = 0.8500 n16 = 1.83400 ν16 = 37.16 r29 = -28.0912 d29 = D4 (variable) r30 = -250.4406 d30 = 2.2000 n17 = 1.57135 ν17 = 52.92 r31 = -132.5105 Aspheric coefficient (first surface) P = 1.0000, E = 0.40108 × 10 ^-6 , F = -0.1726
0 × 10 ^-8 G = 0.22527 × 10 ^-11 , H = -0.19554 × 10 ^-14 (Surface 10) P = 1.0000, E = 0.80578 × 10 ^-6 , F = 0.38063
× 10 ^-8 G = -0.12553 × 10 ^-10 , H = 0.26607 × 10 ^-3 (Surface 17) P = 1.0000, E = 0.18796 × 10 ^-5 , F = 0.16898
× 10 ^-8 G = -0.30787 × 10 ^-10 , H = 0.97607 × 10 ^-13 f 36.2 66.2 131.0 D1 39.258 17.095 0.650 D2 4.907 7.939 23.965 D3 10.682 6.011 0.500 D4 0.650 24.457 30.395 where r1, r2, ... are lenses Radius of curvature of each surface, d1
, D2,... Are the thickness of each lens and the lens interval, n1
, N2, ... are the refractive indices of each lens, ν1, ν2, ...
Is the Abbe number of each lens.

Embodiments 1 and 2 have the structures shown in FIGS. 1 and 2, respectively. In both embodiments, the first lens unit and the fifth lens unit are fixed to the image plane, and the second lens unit ,
The third lens group and the fourth lens group are movable.

In the first embodiment, the focal length is 21.7 to 49.
In step 1, the aspherical surface is used for the first lens unit to mainly correct distortion unique to a wide angle. This increases the degree of freedom for other aberrations.

Embodiment 2 is a wide-angle zoom lens having a focal length of 24.3 to 77.7 in the configuration shown in FIG. 2, and both chromatic aberration and distortion of magnification are corrected well, and spherical aberration is slightly increased on the telephoto side. Although large, aberration is well corrected by the aspherical surface.

Embodiment 3 and Embodiment 4 are as shown in FIGS. 3 and 4, respectively, and the focal length is between 40.2 and 59.8.
This is a four-group configuration in which the fifth lens group fixed during zooming is not used. Further, the aperture ratio is large and is about F / 2.15.

Examples 5 to 7 were designed assuming a lens system having a waterproof or drip-proof mechanism. That is, the first lens group and the fifth lens group are fixed during zooming, and the second to fourth lens groups are moved for zooming.

Embodiment 5 is a zoom lens having the configuration shown in FIG. 5 and having a focal length of 36 to 101.6.

In the sixth embodiment, the configuration shown in FIG.
Embodiment 5 is a zoom lens of 5.9 to 101.91.
It is a configuration similar to. However, in this embodiment, the first lens group is composed of a front group and a rear group, and the rear group is movable during zooming. In this embodiment, chromatic aberration of spherical aberration remains, but except for this point, various aberrations are corrected in a well-balanced manner.

The seventh embodiment has the configuration shown in FIG. 7, and has a focal length of 31.7 to 101.4.

In the eighth embodiment, the focal length is 36 to 131,
It is a high-magnification, wide-angle zoom lens. In this embodiment, the first to fourth lens units are moved during focusing. As described above, focusing other than the first lens group can be practically used as long as the fluctuation of the spherical aberration and the astigmatism is basically small or in the same direction.

The movement amounts x2, x3, x4 of the second, third, and fourth lens units in the first to seventh embodiments are as shown in the following table.

Table x2 x3 x4 Example 1 22.7474 12.2294 18.7074 2 29.6626 19.0706 28.4946 3 16.0318 0.3558 5.3028 4 16.6464 -2.0086 2.5054 5 34.0489 17.8339 17.9489 6 33.4522 16.0122 19.7722 7 35.7106 19.2566 19.2286 Is taken on the x-axis and the y-axis is taken in a direction perpendicular to the optical axis.

Where r is the radius of curvature of the aspheric surface near the optical axis, p is the conic constant, and E, F, G,.

[0054]

The zoom lens and the camera according to the present invention are:
Since the overall length of the zooming lens system is almost constant, a sealed structure is possible, and an optical system that can be sufficiently adapted to the use of a wide-angle system and has a relatively large zoom ratio or has
Camera.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a first embodiment.

FIG. 2 is a sectional view of a second embodiment.

FIG. 3 is a cross-sectional view of a third embodiment.

FIG. 4 is a sectional view of a fourth embodiment.

FIG. 5 is a sectional view of a fifth embodiment.

FIG. 6 is a sectional view of a sixth embodiment.

FIG. 7 is a sectional view of a seventh embodiment.

FIG. 8 is a sectional view of an eighth embodiment.

FIG. 9 is an aberration curve diagram at the wide angle end according to the first embodiment.

FIG. 10 is an aberration curve diagram at the intermediate focal length according to the first embodiment.

FIG. 11 is an aberration curve diagram at the telephoto end according to the first embodiment.

FIG. 12 is an aberration curve diagram at the wide angle end according to the second embodiment.

FIG. 13 is an aberration curve diagram at the intermediate focal length according to the second embodiment.

FIG. 14 is an aberration curve diagram at the telephoto end according to the second embodiment.

FIG. 15 is an aberration curve diagram at the wide angle end according to the third embodiment.

FIG. 16 is an aberration curve diagram at the intermediate focal length according to the third embodiment.

FIG. 17 is an aberration curve diagram at the telephoto end according to the third embodiment.

FIG. 18 is an aberration curve diagram at the wide angle end according to the fourth embodiment.

FIG. 19 is an aberration curve diagram at the intermediate focal length according to the fourth embodiment.

FIG. 20 is an aberration curve diagram at the telephoto end in Example 4.

FIG. 21 is an aberration curve diagram at a wide-angle end according to a fifth embodiment.

FIG. 22 is an aberration curve diagram at an intermediate focal length according to the fifth embodiment.

FIG. 23 is an aberration curve diagram at the telephoto end in Example 5.

FIG. 24 is an aberration curve diagram at the wide angle end according to the sixth embodiment.

FIG. 25 is an aberration curve diagram at the intermediate focal length according to the sixth embodiment.

FIG. 26 is an aberration curve diagram at the telephoto end in Example 6.

FIG. 27 is an aberration curve diagram at the wide angle end according to the seventh embodiment.

FIG. 28 is an aberration curve diagram at the intermediate focal length of the seventh embodiment.

FIG. 29 is an aberration curve diagram at the telephoto end in Example 7.

FIG. 30 is an aberration curve diagram at the wide angle end according to the eighth embodiment.

FIG. 31 is an aberration curve diagram at the wide angle end according to the ninth embodiment.

FIG. 32 is an aberration curve diagram at the wide-angle end in Example 10.

FIG. 33 is a diagram illustrating movement of a lens group during zooming according to the present invention.

FIG. 34 is a diagram showing another example of the movement of the lens group during zooming according to the present invention.

FIG. 35 is a view showing still another example of the movement of the lens group during zooming according to the present invention.

FIG. 36 is a diagram illustrating a movement relationship of the second, third, and fourth lens groups according to the present invention;

FIG. 37 is a diagram showing the movement of a conventional negative leading two-group zoom lens.

FIG. 38 is a view showing the movement of a conventional negative leading type four-unit zoom lens.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G02B 9/00-17/08 G02B 21/02-21/04 G02B 25/00-25/04

Claims (9)

(57) [Claims] A first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a negative refractive power.
A second lens unit including a lens unit, a fourth lens unit having a positive or negative power, and a fifth lens unit having a positive refractive power, wherein the first lens unit and the fifth lens unit are fixed to an image forming surface; , a lens system for performing zooming from the wide-angle end to the telephoto end by moving the third lens group and the fourth lens group, a telephoto of the third lens group
The position at the end is closer to the object than the position at the wide-angle end.
I, and the zoom lens satisfies the following condition. (1) 0.5 <| φ12w / φw | <4.0 (2) 0.05 <| φ34w / φw | <1.5 (3) β3w ・ β4w <β3T ・ β4T where φw is the whole system at the wide-angle end Φ12w is the combined refractive power of the first and second lens groups at the wide-angle end, φ34w is the combined refractive power of the third and fourth lens groups at the wide-angle end, and β3w is the wide-angle end. , Β4w is the paraxial lateral magnification carried by the fourth lens group at the wide-angle end, β3T is the paraxial lateral magnification carried by the third lens group at the telephoto end, and β4T is the paraxial lateral magnification carried at the telephoto end. This is a paraxial lateral magnification carried by the four lens groups. A first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a negative refractive power.
The first lens group is substantially fixed with respect to the image forming surface, and the second lens group, the third lens group, and the fourth lens group are composed of a lens group and a fourth lens group having a positive or negative refractive power. A zoom lens that moves and satisfies the following conditions. (1-1) 0.5 <| φ12w / φw | < 1.1 (2) 0.05 <| φ34w / φw | <1.5 (3) β3w ・ β4w <β3T ・ β4T where φw is at the wide-angle end The refractive power of the entire system, φ12w is the combined refractive power of the first and second lens groups at the wide-angle end, φ34w is the combined refractive power of the third and fourth lens groups at the wide-angle end, and β3w is Β4w is the paraxial lateral magnification carried by the fourth lens group at the wide-angle end, β3T is the paraxial lateral magnification carried by the third lens group at the telephoto end, and β4T is the telephoto end at the wide-angle end. Is the paraxial lateral magnification carried by the fourth lens group in FIG. 3. A camera provided with a zoom lens, comprising :
The zoom lens has a first negative refractive power in order from the object side.
A lens group, a second lens group having a positive refractive power, and a negative refractive power
A third lens group, a positive or negative fourth lens group,
The fifth lens group has a folding power, and the first lens group and the fifth lens group.
Lens group and the third lens group,
By moving the lens group and the fourth lens group,
A lens system that changes the magnification from the corner end to the telephoto end.
The position of the group at the telephoto end is more
Characterized by being on the body side and satisfying the following conditions:
Camera with a zoom lens. (1) 0.5 <| φ12w / φw | <4.0 (2) 0.05 <| φ34w / φw | <1.5 (3) β3w ・ β4w <β3T ・ β4T (4) fw <D where φw Is the refractive power of the entire system at the wide-angle end, and φ12w is
The bending of the combination of the first lens unit and the second lens unit at the corner end
The bending force, φ34w, is the third lens group and the fourth lens at the wide-angle end.
Β3w is the third lens at the wide-angle end
群 4w is the fourth lens at the wide-angle end
3T is the third lens at the telephoto end.
Β4T is the fourth lens at the telephoto end.
Lens unit carries paraxial lateral magnification, fw, at the wide-angle end of the entire lens system.
The focal length, D, is the screen diagonal length. 4. The zoom lens according to claim 1, wherein an aperture stop is arranged in said third lens group. 5. The magnification of the second lens group at the wide angle end is β2
3. The zoom lens according to claim 1, wherein the following condition is satisfied when the magnification at the telephoto end is β2T. β2w <β2T 6. When zooming the zoom lens,
3. The zoom lens according to claim 1, wherein the following condition is satisfied when the amount of movement of the second lens group is x2 and the amount of movement of the fourth lens group is x4. 0.7 <x2 / x4 <10.0 7. The zoom lens according to claim 1, wherein a negative lens component is arranged at the head of said first lens group. 8. The zoom lens according to claim 1, wherein the second lens group includes a doublet in which a positive lens and a negative lens are bonded, and a positive lens. 9. A first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a negative refractive power are arranged in order from the object side.
A second lens unit including a lens unit, a fourth lens unit having a positive or negative power, and a fifth lens unit having a positive refractive power, wherein the first lens unit and the fifth lens unit are fixed to an image forming surface; A zoom lens system that performs zooming from a wide-angle end to a telephoto end by moving a third lens unit and a fourth lens unit, and satisfies the following conditions. (1-2) 1.2 <| φ12w / φw | <4.0 (2) 0.05 <| φ34w / φw | <1.5 (3) β3w ・ β4w <β3T ・ β4T where φw is at the wide-angle end The refractive power of the entire system, φ12w is the combined refractive power of the first and second lens groups at the wide-angle end, φ34w is the combined refractive power of the third and fourth lens groups at the wide-angle end, and β3w is Β4w is the paraxial lateral magnification carried by the fourth lens group at the wide-angle end, β3T is the paraxial lateral magnification carried by the third lens group at the telephoto end, and β4T is the telephoto end at the wide-angle end. Is the paraxial lateral magnification carried by the fourth lens group in FIG.