Zoom lens system

Abstract

A zoom lens system has first to fifth lens units from the object side. The second lens unit has a negative optical power. The other lens units have each a positive optical power. During zooming, the first, third and fourth lens units move along the optical axis to vary the distances between the lens units. The zoom lens system fulfills the conditions 0.01.ltoreq..vertline.f2/fT.vertline..ltoreq.0.20 and 25.ltoreq.(fT/f34W).times.Z.ltoreq.300, where f2 represents the focal length of the second lens unit, fT represents the focal length of the entire zoom lens system at the longest focal length condition, f34W represents the composite focal length of the third and fourth lens units at the shortest focal length condition, and Z represents the zoom ratio.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a zoom lens system, and more particularly, to a high-zoom-ratio and small-size zoom lens system suitable for use as a taking lens.

2. Description of the Prior Art

Previously disclosed high-zoom-ratio zoom lens systems having a zoom ratio of as high as 10.times. include one having positive, negative, positive, negative, positive configuration (Japanese Laid-open Patent Application No. S63-205629, etc.), one having positive, negative, positive, negative, positive, negative configuration (Japanese Laid-open Patent Application No. H4-146407, etc.) and one having positive, negative, negative, positive, positive configuration (Japanese Laid-open Patent Application No. H2-208619, etc.).

However, the above-mentioned zoom lens systems, which are large in total length at the shortest focal length condition, cannot be said to be handy for use as standard zoom lens systems.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a high-performance and high-zoom-ratio zoom lens system that is small in total length.

To achieve the above-mentioned object, a zoom lens system according to a first aspect of the present invention comprises from the object side a first lens unit having a positive optical power, a second lens unit having a negative optical power, a third lens unit having a positive optical power, a fourth lens unit having a positive optical power and a fifth lens unit having a positive optical power, wherein zooming is performed by moving at least the first, third and fourth lens units toward the object side to vary each of the lens unit-to-lens unit distances and the following conditions are fulfilled:

0.01.ltoreq..vertline.f2/fT.ltoreq.0.20 25.ltoreq.(fT/f34W).times.Z.ltoreq.300 where f2 represents the focal length of the second lens unit; fT represents the focal length of the entire zoom lens system at the longest focal length condition; f34W represents the composite focal length of the third and fourth lens units at the shortest focal length condition; and Z represents the zoom ratio.

A zoom lens system according to a second aspect of the present invention comprises the construction according to the first aspect of the present invention, wherein the following condition is further fulfilled:

0.01</f12W/fT<0.15 where f12W represents the composite focal length of the first and second lens units at the shortest focal length condition.

BRIEF DESCRIPTION OF THE DRAWINGS

This and other objects and features of this invention will become clear from the following description, taken in conjunction with the preferred embodiments with reference to the accompanied drawings in which:

FIG. 1 shows the lens construction of a first embodiment;

FIG. 2 shows the lens construction of a second embodiment;

FIG. 3 shows the lens construction of a third embodiment;

FIG. 4 shows the lens construction of a fourth embodiment;

FIG. 5 shows the lens construction of a fifth embodiment;

FIG. 6 shows the lens construction of a sixth embodiment;

FIG. 7 shows the lens construction of a seventh embodiment;

FIGS. 8A to 8I are graphic representations of aberrations in the first embodiment;

FIGS. 9A to 9I are graphic representations of aberrations in the second embodiment;

FIGS. 10A to 10I are graphic representations of aberrations in the third embodiment;

FIGS. 11A to 11I are graphic representations of aberrations in the fourth embodiment;

FIGS. 12A to 12I are graphic representations of aberrations in the fifth embodiment;

FIGS. 13A to 13I are graphic representations of aberrations in the sixth embodiment; and

FIGS. 14A to 14I are graphic representations of aberrations in the seventh embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Zoom lens systems embodying the present invention will hereinafter be described with reference to the drawings. FIGS. 1 to 7 showing the lens constructions of zoom lens systems according to first through seventh embodiments, show the lens arrangements at the shortest focal length condition (W). In the figures, arrows m1 to m5 schematically show the movements of first to fifth lens units Gr1 to Gr5 as the lens is zoomed from the shortest focal length condition (W) to the longest focal length condition (T). In the figures, the surfaces marked with ri (i=1, 2, 3, . . . ) are ith surfaces counted from the object side and the axial distances marked with di (i=1, 2, 3, . . . ) are ith axial distances counted from the object side.

The first to seventh embodiments are five-unit zoom lens systems each comprising from the object side a first lens unit Gr1 having a positive optical power, a second lens unit Gr2 having a negative optical power, a third lens unit Gr3 having a positive optical power, a fourth lens unit Gr4 having a positive optical power and a fifth lens unit Gr5 having a positive optical power wherein zooming is performed by varying each of the lens unit-to-lens unit distances. In zooming from the shortest focal length condition (W) to the longest focal length condition (T), at least the first lens unit Gr1, the third lens unit Gr3 and the fourth lens unit Gr4 are moved toward the object side. Between the most image side surface of the second lens unit Gr2 and the most object side surface of the third lens unit Gr3, an aperture stop S is disposed which is moved together with the third lens unit Gr3 for zooming.

In the first embodiment, the lens units comprise from the object side the following lens elements: The first lens unit Gr1 comprises a doublet lens element consisting of a negative meniscus lens element convex to the object side and a bi-convex positive lens element, and a positive meniscus lens element convex to the object side. The second lens unit Gr2 comprises a negative meniscus lens element convex to the object side, a bi-concave negative lens element, a bi-convex positive lens element and a bi-concave negative lens element. The third lens unit Gr3 comprises a bi-convex positive lens element, a bi-convex positive lens element and a bi-concave negative lens element. The fourth lens unit Gr4 comprises a bi-convex positive lens element, a positive meniscus lens element convex to the image side, a bi-concave negative lens element and a negative meniscus lens element convex to the object side. The fifth lens unit Gr5 comprises a positive meniscus lens element convex to the object side. The following three surfaces are aspherical: the object side surface of the most object side lens element in the second lens unit Gr2(r6) and the object side surface and the image side surface of the third lens element counted from the object side in the fourth lens unit Gr4(r25 and r26). In zooming from the shortest focal length condition (W) to the longest focal length condition (T), the second lens unit Gr2 is moved to describe a locus convex toward the object side, and the first lens unit Gr1 and the third to fifth lens units Gr3 to Gr5 are moved toward the object side.

In the second embodiment, the lens units comprise from the object side the following lens elements: The first lens unit Gr1 comprises a doublet lens element consisting of a negative meniscus lens element convex to the object side and a bi-convex positive lens element, and a positive meniscus lens element convex to the object side. The second lens unit Gr2 comprises a negative meniscus lens element convex to the object side, a bi-concave negative lens element, a bi-convex positive lens element and a bi-concave negative lens element. The third lens unit Gr3 comprises a bi-convex positive lens element, a bi-convex positive lens element and a bi-concave negative lens element. The fourth lens unit Gr4 comprises a bi-convex positive lens element, a positive meniscus lens element convex to the image side, a bi-concave negative lens element and a negative meniscus lens element convex to the object side. The fifth lens unit Gr5 comprises a positive meniscus lens element convex to the object side. The following three surfaces are aspherical: the object side surface of the most object side lens element in the second lens unit Gr2(r6), and the object side surface and the image side surface of the third lens element counted from the object side in the fourth lens unit Gr4(r25 and r26). In zooming from the shortest focal length condition (W) to the longest focal length condition (T), the first to fifth lens units Gr1 to Gr5 are moved toward the object side.

In the third embodiment, the lens units comprise from the object side the following lens elements: The first lens unit Gr1 comprises a doublet lens element consisting of a negative meniscus lens element convex to the object side and a bi-convex positive lens element, and a positive meniscus lens element convex to the object side. The second lens unit Gr2 comprises a negative meniscus lens element convex to the object side, a bi-concave negative lens element, a bi-convex positive lens element and a bi-concave negative lens element. The third lens unit Gr3 comprises a bi-convex positive lens element, a bi-convex positive lens element and a bi-concave negative lens element. The fourth lens unit Gr4 comprises a bi-convex positive lens element, a positive meniscus lens element convex to the image side, a bi-concave negative lens element and a negative meniscus lens element convex to the object side. The fifth lens unit Gr5 comprises a positive meniscus lens element convex to the object side. The following three surfaces are aspherical: the object side surface of the most object side lens element in the second lens unit Gr2(r6), and the object side surface and the image side surface of the third lens element counted from the object side in the fourth lens unit Gr2(r25 and r26). In zooming from the shortest focal length condition (W) to the longest focal length condition (T), the second lens unit Gr2 is moved to describe a locus convex toward the object side, and the first lens unit Gr1 and the third to fifth lens units Gr3 to Gr5 are moved toward the object side.

In the fourth embodiment, the lens units comprise from the object side the following lens elements: The first lens unit Gr1 comprises a doublet lens element consisting of a negative meniscus lens element convex to the object side and a bi-convex positive lens element, and a positive meniscus lens element convex to the object side. The second lens unit Gr2 comprises a negative meniscus lens element convex to the object side, a bi-concave negative lens element, a bi-convex positive lens element and a bi-concave negative lens element. The third lens unit Gr3 comprises a bi-convex positive lens element, a positive meniscus lens element convex to the object side and a bi-concave negative lens element. The fourth lens unit Gr4 comprises a bi-convex positive lens element, a positive meniscus lens element convex to the image side, a bi-concave negative lens element and a positive meniscus lens element convex to the object side. The fifth lens unit Gr5 comprises a negative meniscus lens element concave to the image side and a positive meniscus lens element convex to the object side. The following three surfaces are aspherical: the object side surface of the most object side lens element in the second lens unit Gr2(r6), and the object side surface and the image side surface of the third lens element counted from the object side in the fourth lens unit Gr4(r25 and r26). In zooming from the shortest focal length condition (W) to the longest focal length condition (T), the second and fifth lens units Gr2 and Gr5 are moved toward the object side to draw convex loci, and the first, third and fourth lens units Gr1, Gr3 and Gr4 are moved toward the object side.

In the fifth embodiment, the lens units comprise from the object side the following lens elements: The first lens unit Gr1 comprises a doublet lens element consisting of a negative meniscus lens element convex to the object side and a bi-convex positive lens element, and a positive meniscus lens element convex to the object side. The second lens unit Gr2 comprises a negative meniscus lens element convex to the object side, a bi-concave negative lens element, a bi-convex positive lens element and a bi-concave negative lens element. The third lens unit Gr3 comprises a bi-convex positive lens element, a bi-convex positive lens element and a bi-concave negative lens element. The fourth lens unit Gr4 comprises a bi-convex positive lens element, a positive meniscus lens element convex to the image side, a biconcave negative lens element and a negative meniscus lens element convex to the object side. The fifth lens unit Gr5 comprises a positive meniscus lens element convex to the object side. The following three surfaces are aspherical: the object side surface of the most object side lens element in the second lens unit Gr2(r6), and the object side surface and the image side surface of the third lens element counted from the object side in the fourth lens unit Gr4(r25 and r26). In zooming from the shortest focal length condition (W) to the longest focal length condition (T), the first to fourth lens units Gr1 to Gr4 are moved toward the object side and the fifth lens unit Gr5 is stationary.

In the sixth embodiment, the lens units comprise from the object side the following lens elements: The first lens unit Gr1 comprises a doublet lens element consisting of a negative meniscus lens element convex to the object side and a bi-convex positive lens element, and a positive meniscus lens element convex to the object side. The second lens unit Gr2 comprises a negative meniscus lens element convex to the object side, a bi-concave negative lens element, a bi-convex positive lens element and a negative meniscus lens element convex to the image side. The third lens unit Gr3 comprises a bi-convex positive lens element, a positive meniscus lens element convex to the object side and a bi-concave negative lens element. The fourth lens unit Gr4 comprises a bi-convex positive lens element, a positive meniscus lens element convex to the image side, a bi-concave negative lens element and a positive meniscus lens element convex to the object side. The fifth lens unit Gr5 comprises a positive meniscus lens element convex to the object side. The following three surfaces are aspherical: the object side surface of the most object side lens element in the second lens unit Gr2(r6), and the object side surface and the image side surface of the third lens element counted from the object side in the fourth lens unit Gr4(r25 and r26). In zooming from the shortest focal length condition (W) to the longest focal length condition (T), the second lens unit Gr2 is moved to describe a locus convex toward the object side, and the first lens unit Gr1 and the third to fifth lens units Gr3 to Gr5 are moved toward the object side.

In the seventh embodiment, the lens units comprise from the object side the following lens elements: The first lens unit Gr1 comprises a doublet lens element consisting of a negative meniscus lens element convex to the object side and a bi-convex positive lens element, and a positive meniscus lens element convex to the object side. The second lens unit Gr2 comprises a negative meniscus lens element convex to the object side, a bi-concave negative lens element, a bi-convex positive lens element and a biconcave negative lens element. The third lens unit Gr3 comprises a bi-convex positive lens element, a positive meniscus lens element convex to the object side and a bi-concave negative lens element. The fourth lens unit Gr4 comprises a bi-convex positive lens element, a bi-convex positive lens element, a bi-concave negative lens element and a positive meniscus lens element convex to the object side. The fifth lens unit Gr5 comprises a positive meniscus lens element convex to the object side. The following five surfaces are aspherical: the object side surface of the most object side lens element in the second lens unit Gr2(r6), the object side surface of the most object side lens element in the third lens unit Gr3(r15), the object side surface and the image side surface of the third lens element counted from the object side in the fourth lens unit Gr4(r25 and r26), and the most object side surface of the fifth lens unit Gr5(r29). In zooming from the shortest focal length condition (W) to the longest focal length condition (T), the second lens unit Gr2 is moved to describe a locus convex toward the object side, and the first lens unit Gr1 and the third to fifth lens units Gr3 to Gr5 are moved toward the object side.

Now, reasons will be described why size reduction is difficult in conventional high-magnification zoom lens systems. For example, in a zoom type of positive, negative, positive, negative, positive, negative configuration, in order to reduce the total length, it is necessary to decrease the distance between the first and second lens units on the shorter focal length side to increase the composite negative optical power of the first and second lens units. When the negative composite optical power of the first and second lens units is increased, although the total length is reduced because the degree of retro increases, the optical power of the third and succeeding lens units also increases. It is for this reason that the third and succeeding lens units comprise four lens units. This enables the achievement of a zoom ratio of approximately 10.times.. However, this also increases the size of the third and succeeding lens units. Moreover, in this zoom type, it is necessary to provide some distance between the fourth and fifth lens units to achieve zooming and aberration correction. Consequently, the size of the portion of the third and succeeding lens units further increases, so that the size reduction of the entire lens system is limited. In a zoom type of positive, negative, positive, negative, positive configuration, the third and succeeding lens units comprise three lens units. However, in this type, it is also necessary to provide some distance between the fourth and fifth lens units to achieve zooming and aberration correction, so that the size of the portion of the third and succeeding lens units increases.

In the first to seventh embodiments, to achieve size reduction, a zoom type of positive, negative, positive, positive, positive configuration is employed and zooming is performed by moving at least the first lens unit Gr1, the third lens unit Gr3 and the fourth lens unit Gr4 toward the object side to vary each of the lens unit-to-lens unit distances. Thus, by the arrangement such that the first lens unit Gr1 is not stationary but is moved toward the object side in zooming, size reduction is achieved. By moving the third and fourth lens units Gr3 and Gr4 toward the object side in zooming, the burden imposed on the third and fourth lens units Gr3 and Gr4 for zooming is increased. By increasing the burden imposed on the third and fourth lens units Gr3 and Gr4 for zooming, a high-zoom-ratio zoom lens system is realized.

In the zoom type of positive, negative, positive, positive, positive configuration, increasing the negative composite optical power of the first and second lens units Gr1 and Gr2 at the shortest focal length condition (W) enables the achievement of size reduction of the entire zoom lens system, and increasing the negative optical power of the second lens unit Gr2 enables the achievement of a high zoom ratio. With the increase in the negative optical powers, the positive optical power of the third and succeeding lens units is necessarily increased. Moreover, in order to achieve a high zoom ratio, it is necessary to increase the positive composite optical power of the third and fourth lens units Gr3 and Gr4. When the composite optical power of the third and fourth lens units Gr3 and Gr4 is increased, large aberration (particularly, coma) is generated in the third and fourth lens units Gr3 and Gr4. This aberration can be corrected in the fifth lens unit Gr5. Further, in the fifth lens unit Gr5, image plane correction can be made. To correct aberration generated in the third and fourth lens units Gr3 and Gr4, it is desired that the fifth lens unit Gr5 should have a meniscus lens element convex to the object side.

From the above-described point of view, in the zoom type of positive, negative, positive, positive, positive configuration like the first to seventh embodiments, it is desirable that the condition (1) or (2) shown below should be fulfilled. It is more desirable that both the conditions (1) and (2) should be fulfilled. Fulfilling the conditions (1) and (2) enables the achievement of a zoom lens system that is compact and has high performance in spite of having a high zoom ratio.

0.01.ltoreq..vertline.f2/fT.vertline..ltoreq.0.20 (1) 25.ltoreq.(fT/f34W).times.Z.ltoreq.300 (2) where f2 represents the focal length of the second lens unit Gr2; fT represents the focal length of the entire lens system at the longest focal length condition (T); f34W represents the composite focal length of the third and fourth lens units Gr3 and Gr4 at the shortest focal length condition (W); and Z represents the zoom ratio.

The condition (1) defines the focal length of the second lens unit Gr2. As mentioned previously, in the zoom type of positive, negative, positive, positive, positive configuration, a high zoom ratio is achieved by increasing the optical power of the second lens unit Gr2. However, excessively increasing the optical power makes it difficult to correct aberration. That is, when the lower limit of the condition (1) is exceeded to decrease the focal length of the second lens unit Gr2, although this is advantageous to size reduction, it is difficult to correct aberration (particularly, coma on the shorter focal length side). When the upper limit of the condition (1) is exceeded to increase the focal length of the second lens unit Gr2, compactness is lost.

The condition (2) defines the composite focal length of the third and fourth lens units Gr3 and Gr4. When the lower limit of the condition (2) is exceeded, it is difficult to increase the zoom ratio originating from the third and fourth lens units Gr3 and Gr4, so that it is impossible to achieve a high zoom ratio. In addition, compactness is lost. When the upper limit of the condition (2) is exceeded to decrease the composite focal length of the third and fourth lens units Gr3 and Gr4, although this contributes to a high zoom ratio, aberration (particularly, coma) generated in the third and fourth lens units Gr3 and Gr4 cannot be sufficiently corrected in the fifth lens unit Gr5.

Moreover, from the above-described point of view, in the zoom type of positive, negative, positive, positive, positive configuration like the first to seventh embodiments, it is desired that the condition (3) shown below should be fulfilled. Further, it is more desired that all of the conditions (1) to (3) should be fulfilled. Fulfilling tile condition (3) is effective for reducing the size of a high-zoom-ratio and high-performance zoom lens system.

0.01<.vertline.f12W/fT.vertline.<0.15 (3) where f12W represents the composite focal length of the first and second lens units Gr1 and Gr2 at the shortest focal length condition (W).

When the lower limit of the condition (3) is exceeded to decrease the composite focal length f12W of the first and second lens units Gr1 and Gr2, the optical power of the second lens unit Gr2 is too high, so that it is difficult to correct coma and lateral chromatic aberration at the shortest focal length condition (W). When the upper limit of the condition (3) is exceeded, compactness is lost.

Like in the first to seventh embodiments, in the zoom type of positive, negative, positive, positive, positive configuration in which the third and fourth lens units Gr3 and Gr4 are moved toward the object side in zooming, it is desired that the following condition (4) should be fulfilled:

0.30.ltoreq.D3/D4.ltoreq.0.98 (4) where D4 represents the movement amount of the fourth lens unit Gr4 from the shortest focal length condition (W) to the longest focal length condition (T); and D3 represents the movement amount of the third lens unit Gr3 from the shortest focal length condition (W) to the longest focal length condition (T).

The condition (4) defines the desired distance between the third and fourth lens units Gr3 and Gr4. Making the distance between the third and fourth lens units Gr3 and Gr4 appropriate is effective for correcting the image plane. When the lower limit of the condition (4) is exceeded, the image plane is excessively corrected or the third lens unit Gr3 cannot sufficiently share the zoom ratio. When the third lens unit Gr3 cannot sufficiently share the zoom ratio, in order to increase the zoom ratio shares of other lens units, it is necessary to increase the optical power or the movement amounts of the lens units. As a result, aberration correction becomes difficult and compactness is lost. When the upper limit of the condition (4) is exceeded, sufficient effects of image plane correction cannot be obtained.

Like in the first to seventh embodiments, in the zoom type of positive, negative, positive, positive, positive configuration, it is desired to provide at least one aspherical surface in the second lens unit Gr2. When the optical power of the second lens unit Gr2 is increased in order to reduce the size of the optical system, negative distortion on the shorter focal length side increases or coma on the shorter focal length side increases. Providing an aspherical surface in the second lens unit Gr2 is effective for correcting these aberrations.

Like in the seventh embodiment, in the zoom type of positive, negative, positive, positive, positive configuration, it is desired to provide at least one aspherical surface in the third lens unit Gr3. When the composite optical power of the first and second lens units Gr1 and Gr2 is increased at the shortest focal length condition (W) in order to reduce the size of the optical system, it is necessary to also increase the optical power of the third and succeeding lens units accordingly. However, if the optical power of the third lens unit Gr3 is increased, spherical aberration inclines toward the under side. Providing an aspherical surface in the third lens unit Gr3 is effective for correcting the inclination of spherical aberration toward the under side.

Like in the first to seventh embodiments, in the zoom type of positive, negative, positive, positive, positive configuration, it is desired to provide at least one aspherical surface in the fourth lens unit Gr4. When the composite optical power of the first and second lens units Gr1 and Gr2 at the shortest focal length condition (W) is increased in order to reduce the size of the optical system, it is necessary to also increase the optical power of the third and succeeding lens units accordingly. However, if the optical power of the fourth lens unit Gr4 is increased, coma at the shortest focal length condition (W) is particularly increased. Providing an aspherical surface in the fourth lens unit Gr4 is effective for correcting coma at the shortest focal length condition (W).

Like in the seventh embodiment, in the zoom type of positive, negative, positive, positive, positive configuration, it is desired to provide at least one aspherical surface in the fifth lens unit Gr5. When the size of the optical system is reduced, the angle of off-axial (particularly, rim) incident light increases in the fifth lens unit Gr5, so that coma generated in the third and fourth lens units Gr3 and Gr4 is excessively corrected. Providing an aspherical surface in the fifth lens unit Gr5 is effective in correcting this.

Tables 1 to 7 list the construction data of examples of the zoom lens systems of the first to seventh embodiments, whose lens arrangements are illustrated in FIGS. 1 to 7, respectively.

The constructions of the zoom lens systems embodying the present invention will hereinafter be described more concretely with reference to construction data and graphic representations of aberrations. First to seventh embodiments shown below as examples correspond to the above-described first to seventh embodiments. The lens construction views (FIGS. 1 to 7) showing the first to seventh embodiments show the lens constructions of the corresponding first to seventh embodiments.

In the construction data of the embodiments, ri (i=1, 2, 3, . . . ) represents the radius of curvature of an ith surface counted from the object side, di (i=1, 2, 3, . . . ) represents an ith axial distance counted from the object side, Ni (i=1, 2, 3, . . . ) and vi (i=1, 2, 3, . . . ) represent the refractive index (Nd) and the Abbe number (.nu.d) to the d-line of an ith lens element counted from the object side. In the construction data, the axial distances (variable distances) varied in zooming are axial distances at the shortest focal length condition (W), at the middle focal length condition (M) and at the longest focal length condition (T). The focal lengths f and the F-numbers FNO of the entire lens system corresponding to the focal length conditions (W), (M) and (T) are also shown.

The surfaces marked with asterisks at the radius of curvature ri are aspherical and defined by the following equation (AS) expressing an aspherical surface configuration: ##EQU1## where X represents the displacement from the reference surface in the optical axis direction;

Y represents the height in a direction perpendicular to the optical axis; C represents the paraxial curvature; .epsilon. represents the quadric surface parameter; and Ai represents the aspherical coefficient of the i-th order.

Table 8 shows corresponding values of the conditions (1) to (4) in the embodiments. As is apparent from Table 8, the first to seventh embodiments fulfill the conditions (1) to (4).

FIGS. 8A to 8I through 14A to 14I are graphic representations of aberrations corresponding to the first to seventh embodiments. In the figures, (W), (M) and (T) show aberrations (from the left, spherical aberration, etc., astigmatism and distortion; Y': image height) at the shortest focal length condition, at the middle focal length condition and at the longest focal length condition, respectively. In the figures, the solid line d represents aberration to the d-line and the broken line SC represents sine condition. The broken line DM and the solid line DS represent astigmatisms to the d-line on the meridional image plane and on the sagittal image plane, respectively.

As described above, according to the first and second aspects of the present invention, a high-performance and high-zoom-ratio zoom lens system being small in total length is realized. Moreover, according to the second aspect of the invention, size reduction and higher performance are effectively achieved.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.

TABLE 1______________________________________<< Embodiment 1 >>______________________________________f = 22.5 .about. 68.2 .about. 215.0FNO = 4.1 .about. 5.5 .about. 5.8Radius of Axial Refractive AbbeCurvature Distance Index Number______________________________________{First Lens Unit Gr1 ... Positive}r1 = 112.210 d1 = 1.800 N1 = 1.83400 .nu.1 = 37.05r2 = 52.805 d2 = 6.300 N2 = 1.49310 .nu.2 = 83.58r3 = -477.101 d3 = 0.100r4 = 48.573 d4 = 5.340 N3 = 1.49310 .nu.3 = 83.58r5 = 399.715 d5 = 0.899 .about. 20.582 .about. 50.854{Second Lens Unit Gr2 ... Negative}r6* = 81.522 d6 = 1.000 N4 = 1.61720 .nu.4 = 54.00r7 = 15.450 d7 = 6.630r8 = -36.156 d8 = 1.000 NS = 1.75450 .nu.5 = 51.57r9 = 53.164 d9 = 0.100r10 = 28.759 d10 = 3.510 N6 = 1.75000 .nu.6 = 25.14r11 = -35.866 d11 = 1.120r12 = -21.249 d12 = 1.000 N7 = 1.75450 .nu.7 = 51.57r13 = 177.471 d13 = 22.318 .about. 10.118 .about. 0.700{Aperture Stop S}r14 = .infin. d14 = 0.100{Third Lens Unit Gr3 ... Positive}r15 = 21.882 d15 = 3.180 N8 = 1.48749 .nu.8 = 70.44r16 = -49.561 d16 = 0.100r17 = 20.637 d17 = 3.240 N9 = 1.48749 .nu.9 = 70.44r18 = -93.046 d18 = 1.640r19 = -30.313 d19 = 1.000 N10 = 1.80741 .nu.10 = 31.59r20 = 51.204 d20 = 4.850 .about. 1.282 .about. 0.097{Fourth Lens Unit Gr4 ... Positive}r21 = 22.596 d21 = 3.660 N11 = 1.50378 .nu.11 = 66.89r22 = -32.660 d22 = 0.100r23 = -62.642 d23 = 2.410 N12 = 1.79850 .nu.12 = 22.60r24 = -29.155 d24 = 0.270r25* = -77.590 d25 = 1.000 N13 = 1.77551 .nu.13 = 37.90r26* = 28.487 d26 = 0.100r27 = 13.350 d27 = 1.000 N14 = 1.48749 .nu.14 = 70.44r28 = 12.791 d28 = 5.000 .about. 16.330 .about. 10.897{Fifth Lens Unit Gr5 ... Positive}r29 = 22.703 d29 = 1.510 N15 = 1.75450 .nu.15 = 51.57r30 = 24.860______________________________________[Aspherical Coefficients] r6: .epsilon. = 1.0000 A4 = 0.67660 .times. 10.sup.-5 A6 = -0.38916 .times. 10.sup.-7 A8 = 0.80677 .times. 10.sup.-9 A10 = -0.90846 .times. 10.sup.-11 A12 = 0.66876 .times. 10.sup.-13 A14 = -0.25054 .times. 10.sup.-15 A16 = 0.37459 .times. 10.sup.-18 r25: .epsilon. = 1.0000 A4 = -0.70854 .times. 10.sup.-5 A6 = -0.14836 .times. 10.sup.-7 A8 = -0.83912 .times. 10.sup.-8 A10 = -0.97479 .times. 10.sup.-11 A12 = 0.85091 .times. 10.sup.-12 A14 = 0.21704 .times. 10.sup.-13 A16 = -0.27577 .times. 10.sup.-15 r26: .epsilon. = 1.0000 A4 = 0.65700 .times. 10.sup.-4 A6 = 0.29621 .times. 10.sup.-6 A8 = -0.11288 .times. 10.sup.-7 A10 = -0.31721 .times. 10.sup.-10 A12 = 0.22661 .times. 10.sup.-11 A14 = 0.17391 .times. 10.sup.-13 A16 = -0.36261 .times. 10.sup.-15______________________________________ TABLE 2______________________________________<< Embodiment 2 >>______________________________________f = 22.5 .about. 68.2 .about. 215.0FNO = 4.1 .about. 5.5 .about. 5.8Radius of Axial Refractive AbbeCurvature Distance Index Number______________________________________{First Lens Unit Gr1 ... Positive}r1 = 111.532 d1 = 1.800 N1 = 1.83400 .nu.1 = 37.05r2 = 53.939 d2 = 6.300 N2 = 1.49310 .nu.2 = 83.58r3 = -459.002 d3 = 0.100r4 = 49.474 d4 = 5.340 N3 = 1.49310 .nu.3 = 83.58r5 = 389.658 d5 = 0.899 .about. 21.119 .about. 49.282{Second Lens Unit Gr2 ... Negative}r6* = 81.484 d6 = 1.000 N4 = 1.61720 .nu.= 54.00r7 = 15.452 d7 = 6.630r8 = -36.078 d8 = 1.000 N5 = 1.75450 .nu.5 = 51.57r9 = 54.875 d9 = 0.100r10 = 28.648 d10 = 3.510 N6 = 1.75000 .nu.6 = 25.14r11 = -36.737 d11 = 1.120r12 = -21.151 d12 = 1.000 N7 = 1.75450 .nu.7 = 51.57r13 = 184.647 d13 = 21.762 .about. 9.674 .about. 0.700{Aperture Stop S}r14 = .infin. d14 = 0.100{Third Lens Unit Gr3 ... Positive}r15 = 21.710 d15 = 3.180 N8 = 1.48749 .nu.8 = 70.44r16 = -49.288 d16 = 0.100r17 = 20.752 d17 = 3.240 N9 = 1.48749 .nu.9 = 70.44r18 = -103.029 d18 = 1.640r19 = -30.657 d19 = 1.000 N10 = 1.80741 .nu.10 = 31.59r20 = 52.901 d20 = 4.850 .about. 1.350 .about. 0.450{Fourth Lens Unit Gr4 ... Positive}r21 = 22.630 d21 = 3.660 N11 = 1.50378 .nu.11 = 66.89r22 = -32.955 d22 = 0.100r23 = -59.941 d23 = 2.410 N12 = 1.79850 .nu.12 = 22.60r24 = -29.499 d24 = 0.270r25* = -82.492 d25 = 1.000 N13 = 1.77551 .nu.13 = 37.90r26* = 27.975 d26 = 0.100r27 = 13.222 d27 = 1.000 N14 = 1.48749 .nu.14 = 70.44r28 = 12.872 d28 = 5.000 .about. 16.149 .about. 19.987{Fifth Lens Unit Gr5 ... Positive}r29 = 25.688 d29 = 1.510 N15 = 1.75450 .nu.15 = 51.57r30 = 30.013______________________________________[Aspherical Coefficients] r6: .epsilon. = 1.0000 A4 = 0.73951 .times. 10.sup.-5 A6 = -0.38618 .times. 10.sup.-7 A8 = 0.80394 .times. 10.sup.-9 A10 = -0.91685 .times. 10.sup.-11 A12 = 0.67985 .times. 10.sup.-13 A14 = -0.25355 .times. 10.sup.-15 A16 = 0.37459 .times. 10.sup.-10-18 r25: .epsilon. = 1.0000 A4 = -0.70682 .times. 10.sup.-5 A6 = -0.14312 .times. 10.sup.-7 A8 = -0.84007 .times. 10.sup.-8 A10 = -0.10069 .times. 10.sup.-10 A12 = 0.84118 .times. 10.sup.-12 A14 = 0.21686 .times. 10.sup.-13 A16 = -0.27577 .times. 10.sup.-15 r26: .epsilon. = 1.0000 A4 = 0.65810 .times. 10.sup.-4 A6 = 0.29695 .times. 10.sup.-5 A8 = -0.11289 .times. 10.sup.-7 A10 = -0.32099 .times. 10.sup.-10 A12 = 0.22579 .times. 10.sup.-11 A14 = 0.17298 .times. 10.sup.-1 A16 = -0.36261 .times. 10.sup.-15______________________________________ TABLE 3______________________________________<< Embodiment 3 >>______________________________________f = 22.5 .about. 68.2 .about. 215.0FNO = 4.1 .about. 5.5 .about. 5.8Radius of Axial Refractive AbbeCurvature Distance Index Number______________________________________{First Lens Unit Gr1 ... Positive}r1 = 110.602 d1 = 1.800 N1 = 1.83400 .nu.1 = 37.05r2 = 53.200 d2 = 6.700 N2 = 1.49310 .nu.2 = 83.58r3 = -377.293 d3 = 0.100r4 = 47.435 d4 = 5.400 N3 = 1.49310 .nu.3 = 83.58r5 = 289.611 d5 = 0.899 .about. 22.118 .about. 50.328{Second Lens Unit Gr2 ... Negative}r6* = 83.877 d6 = 1.000 N4 = 1.61720 .nu.4 = 54.00r7 = 14.998 d7 = 6.930r8 = -35.169 d8 = 1.000 N5 = 1.75450 .nu.5 = 51.57r9 = 43.882 d9 = 0.100r10 = 27.783 d10 = 3.440 N6 = 1.75000 .nu.6 = 25.14r11 = -32.700 d11 = 0.940r12 = -20.723 d12 = 1.000 N7 = 1.75450 .nu.7 = 51.57r13 = 241.171 d13 = 21.445 .about. 10.154 .about. 0.700{Aperture Stop S}r14 = .infin. d14 = 0.100{Third Lens Unit Gr3 ... Positive}r15 = 21.489 d15 = 2.927 N8 = 1.48749 .nu.8 = 70.44r16 = -64.867 d16 = 0.100r17 = 21.540 d17 = 3.527 N9 = 1.48749 .nu.9 = 70.44r18 = -66.531 d18 = 1.546r19 = -28.061 d19 = 1.000 N10 = 1.80741 .nu.10 = 31.59r20 = 62.424 d20 = 4.398 .about. 1.437 .about. 0.198{Fourth Lens Unit Gr4 ... Positive}r21 = 22.465 d21 = 3.930 N11 = 1.50378 .nu.11 = 66.89r22 = -30.496 d22 = 0.100r23 = -50.942 d23 = 2.040 N12 = 1.79850 .nu.12 = 22.60r24 = -30.153 d24 = 1.500r25* = -48.453 d25 = 1.000 N13 = 1.77551 .nu.13 = 37.90r26* = 38.014 d26 = 0.100r27 = 14.831 d27 = 1.000 N14 = 1.48749 .nu.14 = 70.44r28 = 13.819 d28 = 5.000 .about. 16.012 .about. 10.219{Fifth Lens Unit Gr5 ... Positive}r29 = 26.798 d29 = 1.650 N15 = 1.75450 .nu.15 = 51.57r30 = 34.248______________________________________[Aspherical Coefficients] r6: .epsilon. = 1.0000 A4 = 0.68630 .times. 10.sup.-5 A6 = -0.35500 .times. 10.sup.-7 A8 = 0.73388 .times. 10.sup.-9 A10 = -0.84946 .times. 10.sup.-11 A12 = 0.64156 .times. 10.sup.-13 A14 = -0.24657 .times. 10.sup.-15 A16 = 0.37584 .times. 10.sup.-18 r25: .epsilon. = 1.0000 A4 = -0.83708 .times. 10.sup.-5 A6 = 0.14399 .times. 10.sup.-8 A8 = -0.88323 .times. 10.sup.-8 A10 = -0.72662 .times. 10.sup.-11 A12 = 0.80843 .times. 10.sup.-12 A14 = 0.21851 .times. 10.sup.-13 A16 = -0.27542 .times. 10.sup.-15 r26: .epsilon. = 1.0000 A4 = 0.67745 .times. 10.sup.-4 A6 = 0.28307 .times. 10.sup.-6 A8 = -0.10127 .times. 10.sup.-7 A10 = -0.41213 .times. 10.sup.-10 A12 = 0.21062 .times. 10.sup.-11 A14 = 0.16310 .times. 10.sup.-13 A16 = -0.33318 .times. 10.sup.-15______________________________________ TABLE 4______________________________________<< Embodiment 4 >>______________________________________f = 22.5 .about. 68.2 .about. 215.0FNO = 4.1 .about. 5.5 .about. 5.8Radius of Axial Refractive AbbeCurvature Distance Index Number______________________________________{First Lens Unit Gr1 ... Positive}r1 = 90.735 d1 = 0.950 N1 = 1.85026 .nu.1 = 32.15r2 = 56.594 d2 = 7.140 N2 = 1.49310 .nu.2 = 83.58r3 = -400.314 d3 = 0.100r4 = 49.902 d4 = 5.100 N3 = 1.49310 .nu.3 = 83.58r5 = 201.322 d5 = 0.899 .about. 22.153 .about. 47.451{Second Lens Unit Gr2 ... Negative}r6* = 80.816 d6 = 0.950 N4 = 1.80750 .nu.4 = 35.43r7 = 16.132 d7 = 6.570r8 = -34.551 d8 = 0.950 N5 = 1.56873 .nu.5 = 63.10r9 = 52.109 d9 = 0.100r10 = 27.252 d10 = 3.830 N6 = 1.79850 .nu.6 = 22.60r11 = -53.451d11 = 1.400r12 = -24.606 d12 = 0.950 N7 = 1.78831 .nu.7 = 47.32r13 = 193.497 d13 = 25.382 .about. 12.193 .about. 0.700{Aperture Stop S}r14 = .infin. d14 = 0.100{Third Lens Unit Gr3 ... Positive}r15 = 14.769 d15 = 5.770 N8 = 1.48749 .nu.8 = 70.44r16 = -37.788 d16 = 0.100r17 = 18.837 d17 = 2.540 N9 = 1.48749 .nu.9 = 70.44r18 = 13997.761 d18 = 1.440r19 = -21.158 d19 = 0.950 N10 = 1.80741 .nu.10 = 31.59r20 = 46.332 d20 = 3.860 .about. 1.100 .about. 1.066{Fourth Lens Unit Gr4 ... Positive}r21 = 34.358 d21 = 3.250 N11 = 1.51823 .nu.11 = 58.96r22 = -18.645 d22 = 0.100r23 = -26.459 d23 = 1.680 N12 = 1.80518 .nu.12 = 25.43r24 = -17.522 d24 = 0.100r25* = -24. 716 d25 = 0.950 N13 = 1.77250 .nu.13 = 49.77r26* = 31.031 d26 = 0.100r27 = 15.216 d27 = 1.090 N14 = 1.51680 .nu.14 = 64.20r28 = 16.756 d28 = 1.000 .about. 9.928 .about. 21.615{Fifth Lens Unit Gr5 ... Positive}r29 = 22.882 d29 = 0.900 N15 = 1.85000 .nu.15 = 40.04r30 = 19.232 d30 = 0.500r31 = 20.841 d31 = 2.800 N16 = 1.55232 .nu.16 = 63.42r32 = 51.194______________________________________[Aspherical Coefficients] r6: .epsilon. = 1.0000 A4 = 0.35804 .times. 10.sup.-5 A6 = -0.26375 .times. 10.sup.-7 A8 = 0.70370 .times. 10.sup.-9 A10 = -0.92104 .times. 10.sup.-11 A12 = 0.66673 .times. 10.sup.-13 A14 = -0.23702 .times. 10.sup.-15 A16 = 0.32665 .times. 10.sup.-18 r25: .epsilon. = 1.0000 A4 = -0.31615 .times. 10.sup.-4 A6 = -0.32752 .times. 10.sup.-6 A8 = -0.10688 .times. 10.sup.-7 A10 = -0.20845 .times. 10.sup.-10 A12 = 0.16308 .times. 10.sup.-11 A14 = 0.38056 .times. 10.sup.-13 A16 = -0.62701 .times. 10.sup.-15 r26: .epsilon. = 1.0000 A4 = 0.71389 .times. 10.sup.-4 A6 = 0.57136 .times. 10.sup.-7 A8 = -0.11126 .times. 10.sup.-7 A10 = 0.25719 .times. 10.sup.-10 A12 = 0.23666 .times. 10.sup.-11 A14 = 0.12981 .times. 10.sup.-13 A16 = -0.43066 .times. 10.sup.-15______________________________________ TABLE 5______________________________________<< Embodiment 5 >>______________________________________f = 22.5 .about. 68.2 .about. 215.0FNO = 4.1 .about. 5.5 .about. 5.8Radius of Axial Refractive AbbeCurvature Distance Index Number______________________________________{First Lens Unit Gr1 ... Positive}r1 = 107.421 d1 = 1.800 N1 = 1.83400 .nu.1 = 37.05r2 = 53.902 d2 = 6.400 N2 = 1.49310 .nu.2 = 83.58r3 = -386.515 d3 = 0.100r4 = 53.023 d4 = 5.340 N3 = 1.49310 .nu.3 = 83.58r5 = 693.135 d5 = 0.899 .about. 23.977 .about. 49.067{Second Lens Unit Gr2 ... Negative}r6* = 85.521 d6 = 1.000 N4 = 1.61720 .nu.4 = 54.00r7 = 15.211 d7 = 6.630r8 = -35.778 d8 = 1.000 N5 = 1.75450 .nu.5 = 51.57r9 = 45.101 d9 = 0.100r10 = 27.849 d10 = 3.510 N6 = 1.75000 .nu.6 = 25.14r11 = -36.989 d11 = 1.120r12 = -21.082 d12 = 1.000 N7 = 1.75450 .nu.7 = 51.57r13 = 374.638 d13 = 20.515 .about. 9.987 .about. 0.700{Aperture Stop S}r14 = .infin. d14 = 0.500{Third Lens Unit Gr3 ... Positive}r15 = 21.738 d15 = 3.200 N8 = 1.48749 .nu.8 = 70.44r16 = -55.138 d16 = 0.100r17 = 21.126 d17 = 3.240 N9 = 1.48749 .nu.9 = 70.44r18 = -111.760 d18 = 1.640r19 = -31.278 d19 = 1.000 N10 = 1.80741 .nu.10 = 31.59r20 = 59.812 d20 = 4.850 .about. 1.350 .about. 0.450{Fourth Lens Unit Gr4 ... Positive}r21 = 22.840 d21 = 3.660 N11 = 1.50378 .nu.11 = 66.89r22 = -31.960 d22 = 0.100r23 = -55.493 d23 = 2.410 N12 = 1.79850 .nu.12 = 22.60r24 = -29.617 d24 = 0.270r25* = -86 .437 d25 = 1.000 N13 = 1.77551 .nu.13 = 37.90r26* = 29.561 d26 = 0.100r27 = 13.303 d27 = 1.000 N14 = 1.48749 .nu.14 = 70.44r28 = 13.105 d28 = 5.000 .about. 35.588 .about. 49.740{(Fifth Lens Unit Gr5 ... Positive}r29 = 25.597 d29 = 1.510 N15 = 1.75450 .nu.15 = 51.57r30 = 28.950______________________________________[Aspherical Coefficients] r6: .epsilon. = 1.0000 A4 = 0.69611 .times. 10.sup.-5 A6 = -0.37206 .times. 10.sup.-7 A8 = 0.76950 .times. 10.sup.-9 A10 = -0.94276 .times. 10.sup.-11 A12 = 0.70697 .times. 10.sup.-13 A14 = -0.26153 .times. 10.sup.-15 A16 = 0.37459 .times. 10.sup.-18 r25: .epsilon. = 1.0000 A4 = -0.71695 .times. 10.sup.-5 A6 = -0.15748 .times. 10.sup.-7 A8 = -0.84010 .times. 10.sup.-8 A10 = -0.10079 .times. 10.sup.-10 A12 = 0.83934 .times. 10.sup.-12 A14 = 0.21563 .times. 10.sup.-13 A16 = -0.27577 .times. 10.sup.-15 r26: .epsilon. = 1.0000 A4 = 0.65921 .times. 10.sup.-4 A6 = 0.29931 .times. 10.sup.-6 A8 = -0.11278 .times. 10.sup.-7 A10 = -0.32202 .times. 10.sup.-10 A12 = 0.22495 .times. 10.sup.-11 A14 = 0.17170 .times. 10.sup.-13 A16 = -0.36261 .times. 10.sup.-15______________________________________ TABLE 6______________________________________<< Embodiment 6 >>______________________________________f = 22.5 .about. 85.0 .about. 312.0FNO = 4.1 .about. 5.5 .about. 5.8Radius of Axial Refractive AbbeCurvature Distance Index Number______________________________________{First Lens Unit Gr1 ... Positive}r1 = 100.253 d1 = 1.600 N1 = 1.83400 .nu.1 = 37.05r2 = 53.919 d2 = 7.500 N2 = 1.49310 .nu.2 = 83.58r3 = -1140.485 d3 = 0.100r4 = 53.626 d4 = 6.200 N3 = 1.49310 v3 = 83.58r5 = 415.515 d5 = 0.899 .about. 33.934 .about. 60.018{Second Lens Unit Gr2 ... Negative}r6 = 89.213 d6 = 1.000 N4 = 1.80420 .nu.4 = 46.50r7 = 16.009 d7 = 6.930r8 = -40.001 d8 = 1.000 NS = 1.75450 .nu.5 = 51.57r9 = 50.505 d9 = 0.100r10 = 30.758 d10 = 3.440 N6 = 1.75000 .nu.6 = 25.14r11 = -30.700 d11 = 1.100r12 = -20.939 d12 = 1.000 N7 = 1.75450 .nu.7 = 51.57r13 = -1283.532 d13 = 27.519 .about. 14.252 .about. 0.700{Aperture Stop S}r14 = .infin. d14 = 0.100{Third Lens Unit Gr3 ... Positive}r15 = 19.662 d15 = 4.100 N8 = 1.48749 .nu.8 = 70.44r16 = -55.350 d16 = 0.100r17 = 21.253 d17 = 3.527 N9 = 1.48749 .nu.9 = 70.44r18 = 369.133 d18 = 1.546r19 = -31.623 d19 = 1.000 N10 = 1.80741 .nu.10 = 31.59r20 = 45.095 d20 = 4.398 .about. 1.437 .about. 0.198{Fourth Lens Unit Gr4 ... Positive}r21 = 21.838 d21 = 3.930 N11 = 1.51823 .nu.11 = 58.96r22 = -37.980 d22 = 0.100r23 = -908.612 d23 = 2.040 N12 = 1.75000 .nu.12 = 25.14r24 = -40.900 d24 = 1.500r25* = -56 .331 d25 = 1.000 N13 = 1.83400 .nu.13 = 37.05r26* = 27.611 d26 = 0.100r27 = 15.015 d27 = 1.000 N14 = 1.48749 .nu.14 = 70.44r28 = 15.081d28 = 5.000 .about. 17.988 .about. 16.292{Fifth Lens Unit Gr5 ... Positive}r29 = 26.651 d29 = 1.645 N15 = 1.71300 .nu.15 = 53.93r30 = 32.166______________________________________[Aspherical Coefficients] r6: .epsilon. = 1.0000 A4 = 0.52706 .times. 10.sup.-5 A6 = -0.22246 .times. 10.sup.-7 A8 = 0.71694 .times. 10.sup.-9 A10 = -0.92114 .times. 10.sup.-11 A12 = 0.66032 .times. 10.sup.-13 A14 = -0.24657 .times. 10.sup.-15 A16 = 0.37584 .times. 10.sup.-18 r25: .epsilon. = 1.0000 A4 = -0.56236 .times. 10.sup.-5 A6 = 0.84829 .times. 10.sup.-8 A8 = -0.87959 .times. 10.sup.-8 A10 = -0.88183 .times. 10.sup.-11 A12 = 0.79028 .times. 10.sup.-12 A14 = 0.21851 .times. 10.sup.-13 A16 = -0.27542 .times. 10.sup.-15 r26: .epsilon. = 1.0000 A4 = 0.69231 .times. 10.sup.-4 A6 = 0.29030 .times. 10.sup.-6 A8 = -0.10139 .times. 10.sup.-7 A10 = -0.41417 .times. 10.sup.-10 A12 = 0.21030 .times. 10.sup.-11 A14 = 0.16310 .times. 10.sup.-13 A16 = -0.33318 .times. 10.sup.-15______________________________________ TABLE 7______________________________________<< Embodiment 7 >>______________________________________f = 22.5 .about. 85.0 .about. 312.0FNO = 4.1 .about. 5.5 .about. 5.8Radius of Axial Refractive AbbeCurvature Distance Index Number______________________________________{First Lens Unit Gr1 ... Positive}r1 = 100.707 d1 = 1.600 N1 = 1.83400 .nu.1 = 37.05r2 = 53.500 d2 = 7.800 N2 = 1.49310 .nu.2 = 83.58r3 = -1206.520 d3 = 0.100r4 = 52.540 d4 = 6.500 N3 = 1.49310 .nu.3 = 83.58r5 = 387.306 d5 = 0.899 .about. 33.111 .about. 59.391{Second Lens Unit Gr2 ... Negative}r6* = 73.079 d6 = 1.000 N4 = 1.80420 .nu.4 = 46.50r7 = 15.683 d7 = 6.930r8 = -40.462 d8 = 1.000 N5 = 1.75450 .nu.5 = 51.57r9 = 69.678 d9 = 0.100r10 = 28.716 d10 = 3.440 N6 = 1.75000 .nu.6 = 25.14r11 = -35.706 d11 = 1.100r12 = -24.416 d12 = 1.000 N7 = 1.75450 .nu.7 = 51.57r13 = 94.533 d13 = 26.777 .about. 13.862 .about. 0.700{Aperture Stop S}r14 = .infin. d14 = 0.100{Third Lens Unit Gr3 ... Positive}r15* = 19.493 d15 = 4.100 N8 = 1.48749 .nu.8 = 70.44r16 = -74.560 d16 = 0.100r17 = 19.077 d17 = 3.527 N9 = 1.48749 .nu.9 = 70.44r18 = 2044.363 d18 = 1.546r19 = -36.938 d19 = 1.000 N10 = 1.80741 .nu.10 = 31.59r20 = 33.157 d20 = 4.398 .about. 1.437 .about. 0.198{Fourth Lens Unit Gr4 ... Positive}r21 = 21.455 d21 = 3.930 N11 = 1.51680 .nu.11 = 64.20r22 = -46.318 d22 = 0.100r23 = 179.187 d23 = 2.040 N12 = 1.75000 .nu.12 = 25.14r24 = -38.788 d24 = 1.500r25* = -51.159 d25 = 1.000 N13 = 1.83400 .nu.13 = 37.05r26* = 26.150 d26 = 0.100r27 = 14.706 d27 = 1.000 N14 = 1.48749 .nu.14 = 70.44r28 = 15.197 d28 = 5.000 .about. 17.636 .about. 15.551{Fifth Lens Unit Gr5 ... Positive}r29* = 20.904 d29 = 1.645 N15 = 1.71300 .nu.15 = 53.93r30 = 23.686______________________________________[Aspherical Coefficients] r6: .epsilon. = 1.0000 A4 = 0.22917 .times. 10.sup.-5 A6 = -0.22836 .times. 10.sup.-7 A8 = 0.75510 .times. 10.sup.-9 A10 = -0.96274 .times. 10.sup.-11 A12 = 0.67169 .times. 10.sup.-13 A14 = -0.24702 .times. 10.sup.-15 A16 = 0.37318 .times. 10.sup.-18 r15: .epsilon. = 1.0000 A4 = -0.24149 .times. 01.sup.-5 A6 = -0.17275 .times. 10.sup.-7 A8 = 0.15289 .times. 10.sup.-9 A10 = 0.14656 .times. 10.sup.-11 A12 = -0.14069 .times. 10.sup.-13 r25: .epsilon. = 1.0000 A4 = -0.72345 .times. 10.sup.-5 A6 = -0.64833 .times. 10.sup.-8 A8 = -0.87712 .times. 10.sup.-8 A10 = -0.81898 .times. 10.sup.-11 A12 = 0.79533 .times. 10.sup.-12 A14 = 0.21851 .times. 10.sup.-13 A16 = -0.27542 .times. 10.sup.-15 r26: .epsilon. = 1.0000 A4 = 0.70463 .times. 10.sup.-4 A6 = 0.30519 .times. 10.sup.-6 A8 = -0.10149 .times. 10.sup.-7 A10 = -0.41997 .times. 10.sup.-10 A12 = 0.20979 .times. 10.sup.-11 A14 = 0.16310 .times. 10.sup.-13 A16 = -0.33318 .times. 10.sup.-15 r29: .epsilon. = 1.0000 A4 = -0.48841 .times. 10.sup.-6 A6 = -0.37160 .times. 10.sup.-8 A8 = -0.10500 .times. 10.sup.-9 A10 = 0.35226 .times. 10.sup.-12______________________________________ TABLE 8______________________________________Cond. (1) Cond. (2) Cond. (3) Cond. (4).parallel.f2/fT.parallel. (fT/f34W)xZ .parallel.f12W/fT.parallel. D3/D4______________________________________Emb. 1 0.07 81.7 0.09 0.87Emb. 2 0.07 81.7 0.09 0.90Emb. 3 0.07 82.7 0.09 0.88Emb. 4 0.07 74.66 0.10 0.93Emb. 5 0.07 82.18 0.09 0.90Emb. 6 0.05 157.5 0.06 0.90Emb. 7 0.05 161.5 0.06 0.90______________________________________

Claims

1. A zoom lens system comprising, from the object side:

a first lens unit having a positive optical power;

a second lens unit having a negative optical power;

a third lens unit having a positive optical power;

a fourth lens unit having a positive optical power; and

a fifth lens unit having a positive optical power,

wherein said first, third and fourth lens units are moveable along an optical axis so that distances between the lens units vary during zooming,

wherein the zoom lens system fulfills the following conditions:

0.01.ltoreq..vertline.f2/fT.vertline..ltoreq.0.20

25.ltoreq.(fT/f34W).times.Z .ltoreq.300

where

f2 represents a focal length of the second lens unit;

fT represents a focal length of the entire zoom lens system at a longest focal length condition;

f34W represents a composite focal length of the third and fourth lens units at a shortest focal length condition; and

Z represents a zoom ratio.

2. A zoom lens system in accordance with claim 1, wherein said fifth lens unit has a meniscus lens element having a convex surface on the object side.

3. A zoom lens system in accordance with claim 1, wherein said zoom lens system fulfills the following condition:

0.30.ltoreq.D3/D4.ltoreq.0.98

where

D3 represents a moving amount of the third lens unit during zooming from a shortest focal length condition to a longest focal length condition; and

D4 represents a moving amount of the fourth lens unit during zooming from a shortest focal length condition to a longest focal length condition.

4. A zoom lens system in accordance with claim 1, wherein said second lens unit has an aspherical surface.

5. A zoom lens system in accordance with claim 1, wherein said third lens unit has an aspherical surface.

6. A zoom lens system in accordance with claim 1, wherein said fourth lens unit has an aspherical surface.

7. A zoom lens system in accordance with claim 1, wherein said fifth lens unit has an aspherical surface.

8. A zoom lens system in accordance with claim 1, wherein in zooming from a shortest focal length condition to a longest focal length condition said fifth lens unit moves along the optical axis to describe a locus convex toward the object side.

9. A zoom lens system consisting of, from the object side:

a first lens unit having a positive optical power;

a second lens unit having a negative optical power;

a third lens unit having a positive optical power;

a fourth lens unit having a positive optical power; and

a fifth lens unit having a positive optical power,

wherein said first, third and fourth lens units move along the optical axis so that distances between the lens units vary during zooming,

wherein the zoom lens system fulfills the following condition:

25.ltoreq.(fT/f34W).times.Z.ltoreq.300

where

fT represents a focal length of the entire zoom lens system at a longest focal length condition;

f34W represents a composite focal length of the third and fourth lens units at a shortest focal length condition; and

Z represents a zoom ratio.

10. A zoom lens system in accordance with claim 9, wherein said fifth lens unit has a meniscus lens element having a convex surface on the object side.

11. A zoom lens system in accordance with claim 9, wherein said zoom lens system fulfills the following condition:

0.30.ltoreq.D3/D4.ltoreq.0.98

where

D3 represents a moving amount of the third lens unit during zooming from a shortest focal length condition to a longest focal length condition; and

D4 represents a moving amount of the fourth lens unit during zooming from a shortest focal length condition to a longest focal length condition.

12. A zoom lens system comprising, from the object side:

a first lens unit having a positive optical power;

a second lens unit having a negative optical power;

a third lens unit having a positive optical power;

a fourth lens unit having a positive optical power; and

a fifth lens unit having a positive optical power,

wherein said first, third and fourth lens units are moveable along an optical axis so that distances between the lens units vary during zooming,

wherein the zoom lens system fulfills the following conditions:

0.01.ltoreq..vertline.f2/fT.vertline..ltoreq.0.20

25.ltoreq.(fT/f34W).times.Z.ltoreq.300

0.01<.vertline.f12W/fT.vertline.<0.15

where

f2 represents a focal length of the second lens unit;

fT represents a focal length of the entire zoom lens system at a longest focal length-condition;

f34W represents a composite focal length of the third and fourth lens units at a shortest focal length condition;

Z represents a zoom ratio; and

f12W represents a composite focal length of the first and second lens units at a shortest focal length condition.

13. A zoom lens system in accordance with claim 12, wherein said zoom lens system fulfils the following condition:

0.30.ltoreq.D3/D4.ltoreq.0.98

where

D3 represents a moving amount of the third lens unit during zooming from a shortest focal length condition to a longest focal length condition; and

D4 represents a moving amount of the fourth lens unit during zooming from a shortest focal length condition to a longest focal length condition.

14. A zoom lens system consisting of, from the object side:

a first lens unit having a positive optical power;

a second lens unit having a negative optical power;

a third lens unit having a positive optical power;

a fourth lens unit having a positive optical power; and

a fifth lens unit having a positive optical power,

wherein said first, third and fourth lens units are moveable along an optical axis so that distances between the lens units vary during zooming,

wherein the zoom lens system fulfills the following conditions:

0.01.ltoreq..vertline.f2/fT.vertline..ltoreq.0.20

0.01<.vertline.f12W/fT.vertline.<0.15

where

f2 represents a focal length of the second lens unit;

fT represents a focal length of the entire zoom lens system at a longest focal length condition; and

f12W represents a composite focal length of the first and second lens units at a shortest focal length condition.

15. A zoom lens system consisting of, from the object side:

a first lens unit having a positive optical power;

a second lens unit having a negative optical power;

a third lens unit having a positive optical power;

a fourth lens unit having a positive optical power; and

a fifth lens unit having a positive optical power,

wherein said first, third and fourth lens units are moveable along an optical axis so that distances between the lens units vary during zooming,

wherein the zoom lens system fulfills the following conditions:

0.01<.vertline.f12W/fT.vertline.<0.15

25.ltoreq.(fT/f34W).times.Z.ltoreq.300

where

fT represents a focal length of the entire zoom lens system at a longest focal length condition;

f34W represents a composite focal length of the third and fourth lens units at a shortest focal length condition;

Z represents a zoom ratio; and

f12W represents a composite focal length of the first and second lens units at a shortest focal length condition.

16. A zoom lens system comprising, from the object side:

a first lens unit having a positive optical power;

a second lens unit having a negative optical power;

a third lens unit having a positive optical power;

a fourth lens unit having a positive optical power;

a fifth lens unit having a positive optical power;

wherein for zooming from a shortest focal length condition to a longest focal length condition said first, third and fourth lens units are moveable along an optical axis toward the object side and said second lens unit is moveable along the optical axis to describe a locus convex toward the object side, and

wherein the lens system fulfills the following condition:

0.01<.vertline.f12W/fT.vertline.<0.15

where

f12W represents a composite focal length of the first and second lens units at a shortest focal length condition; and

fT represents a focal length of the entire zoom lens unit.