# Patent

## Title
Zoom lens system and camera incorporating the same

## Abstract

A zoom lens system, with a new structure that exhibits high optical performance over the entirety of a zoom range and the entirety of a focusing range, is disclosed. This zoom lens system comprises, in order from an object side to an image side: a front lens group which includes a plurality of lens units that move during zooming; a lens unit with negative optical power which moves during zooming and moves towards the object side during focusing from an infinity object to a close-distance object; and a lens unit with positive optical power which does not move for zooming.

## Background
This is a divisional of prior application Ser. No. 10/737,150, filed Dec. 15, 2003, to which priority under 35 U.S.C. § 120 is claimed.


BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a zoom lens system that is favorable for a single-lens reflex camera, digital still camera, video camera, film camera, etc., and exhibits good optical performance even while covering a wide-angle range and being of large aperture diameter.
2. Description of the Related Art
As a prior-art image taking lens for a single-lens reflex camera, there is known a zoom lens, in which lens units with negative, positive, negative, and positive refractive powers are disposed in that order from an object side to an image side (Japanese Laid-open Patent Application “1” to “6”).
Since this zoom type lens has a lens unit with negative refractive power positioned at the front and is a so-called negative lead type lens, it is suited for realizing a wider view angle at the wide-angle end. Meanwhile in regard to the telephoto end, since the first lens unit and the second lens unit form a front component with positive refractive power as a whole and the third lens unit and the fourth lens unit form a rear component with negative refractive power as a whole, the optical system can be arranged as a telephoto type lens system as a whole.
Meanwhile there is also known an optical system, wherein a lens unit with positive refractive power is added to the zoom type lens, constituted of the abovementioned four lens units, to further improve the optical performance (Japanese Laid-open Patent Application “7”).
There is also known an optical system in which a lens unit with negative refractive power is added (Japanese Patent Publication “8”).
Also as focusing methods of a zoom lens, there are known the so-called front focus method, wherein the first lens unit at the most object side is moved, and the so-called inner focus or rear focus method, wherein lens units from the second lens unit and rearwards are moved.
Generally with an inner focus or rear focus type zoom lens, since the effective ray diameter of the first lens unit can be made small in comparison to a front focus type zoom lens, the advantage that the overall lens system can be made compact is provided. Also, since comparatively compact and lightweight lens units are moved to perform focusing, the characteristic of facilitating rapid focusing, especially in autofocus cameras, which have become the mainstream recently, is provided.
As such a zoom lens employing an inner focus or rear focus method, the present applicant has proposed in a so-called positive lead type zoom lens, having, in order from the object side to the image side, a first lens unit with positive refractive power, a second lens unit with negative refractive power, and a rear lens group with positive refractive power as a whole, and with which zooming is performed by varying the air spacing of the respective lens units, a zoom lens wherein a focusing lens unit with negative refractive power is disposed as a part of the rear lens group and this focusing lens unit is moved to the image side to perform focusing from an infinity object to a close-distance object (Japanese Laid-open Patent Application “9” to “12”).
[Japanese Laid-open Patent Application and Japanese Patent Publication]


    “1”:Japanese Laid-open Patent Application No.H2(1990)-201310 (corresponding to U.S. Pat. No.5,000,550)
    “2”:Japanese Laid-open Patent Application No.H2(1990)-296208 (corresponding to U.S. Pat. No.5,000,550)
    “3”:Japanese Laid-open Patent Application No.H4(1992)-29109
    “4”:Japanese Laid-open Patent Application No.H4(1992)-29110
    “5”:Japanese Laid-open Patent Application No.H7(1995)-261084 (corresponding to U.S. Pat. No.5,710,669)
    “6”:Japanese Laid-open Patent Application No.H5(1993)-173071 (corresponding to U.S. Pat. No.5,276,553)
    “7”:Japanese Laid-open Patent Application No.H4(1992)-264412 (corresponding to U.S. Pat. No.5,229,886)
    “8”:Japanese Patent Publication No.2587218
    “9”:Japanese Laid-open Patent Application No.H3(1991)-225307 (corresponding to U.S. Pat. No.5,241,421)
    “10”:Japanese Laid-open Patent Application No.H3(1991)-225310 (corresponding to U.S. Pat. No.5,241,421)
    “11”:Japanese Laid-open Patent Application No.H4(1992)-186211 (corresponding to U.S. Pat. No.5,189,557)
    “12”:Japanese Laid-open Patent Application No.H4(1992) -186212 (corresponding to U.S. Pat. No.5,189,557)


A zoom lens, in which lens units with negative, positive, negative, and positive refractive powers are disposed in that order from the object side to the image side, and a zoom lens, which is an application of the abovementioned zoom lens and in which lens units with negative, positive, negative, and positive refractive powers as well as a rear lens group are disposed, are favorable as zoom lenses of wide view angle. However, when an attempt is made to set the focal length and F number at the telephoto side to desirable values and shorten the focal length at the wide-angle side while maintaining the optical performance, the overall lens system generally becomes large. This thus makes the prior-art zoom lenses unable to meet the demands made on zoom lenses for recent optical equipment, which are being made significantly compact.
Meanwhile as another issue of wide-angle zoom lenses, it is difficult to perform focusing to a close-distance object while maintaining good optical performance.
For example, with the generally employed method of focusing from an infinity object to a close-distance object by moving the first lens unit with negative refractive power towards the object side, the front lens diameter becomes large as the optical system is made wider in view angle. Though various focusing methods have been proposed to resolve this problem, all of these have the problem, though differing in degree, that the overall lens system becomes large.
For example, if the close-distance image taking distance is to be made short, the space for movement of the focusing lens unit had to be made large and this caused to the drive system to become large, the overall optical system to become large, and the image performance for close-distance image taking to degrade due to the aberration variations accompanying the focusing process.
Though an inner focus type arrangement has the abovementioned characteristics, when the realization of a wider view angle is attempted, the variations of the various aberrations that accompany focusing become significant and it becomes extremely difficult to maintain good optical performance.
SUMMARY 0F THE INVENTION
An object of the present invention is to provide a zoom lens, with which a wide view angle is realized and yet with which the various aberration variations that accompany zooming and focusing are reduced and high optical performance is provided over the entire zooming range and the entire focusing range.
In order to achieve the above object, a zoom lens system of one aspect of the present invention comprises, in order from an object side to an image side, a front lens group which includes a plurality of lens units that moves during zooming; a lens unit with negative optical power which moves during zooming and moves towards the image side during focusing from an infinity object to a close-distance object; and a lens unit with positive optical power, which does not move for zooming.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a zoom lens system of Embodiment 1.
FIG. 2 is aberration diagrams of the zoom lens system of Embodiment 1 when set at the wide-angle end and focused on an infinity object.
FIG. 3 is aberration diagrams of the zoom lens system of Embodiment 1 when set at an intermediate zoom position and focused on an infinity object.
FIG. 4 is aberration diagrams of the zoom lens system of Embodiment 1 when set at the telephoto end and focused on an infinity object.
FIG. 5 is aberration diagrams of the zoom lens system of Embodiment 1 when set at the wide-angle end and focused on an object at 500 mm (from the image plane).
FIG. 6 is aberration diagrams of the zoom lens system of Embodiment 1 when set at the intermediate zoom position and focused on an object at 500 mm (from the image plane).
FIG. 7 is aberration diagrams of the zoom lens system of Embodiment 1 when set at the telephoto end and focused on an object at 500 mm (from the image plane).
FIG. 8 is a sectional view of a zoom lens system of Embodiment 2.
FIG. 9 is aberration diagrams of the zoom lens system of Embodiment 2 when set at the wide-angle end and focused on an infinity object.
FIG. 10 is aberration diagrams of the zoom lens system of Embodiment 2 when set at an intermediate zoom position and focused on an infinity object.
FIG. 11 is aberration diagrams of the zoom lens system of Embodiment 2 when set at the telephoto end and focused on an infinity object.
FIG. 12 is aberration diagrams of the zoom lens system of Embodiment 2 when set at the wide-angle end and focused on an object at 500 mm (from the image plane).
FIG. 13 is aberration diagrams of the zoom lens system of Embodiment 2 when set at the intermediate zoom position and focused on an object at 500 mm (from the image plane).
FIG. 14 is aberration diagrams of the zoom lens system of Embodiment 2 when set at the telephoto end and focused on an object at 500 mm (from the image plane).
FIG. 15 is a sectional view of a zoom lens system of Embodiment 3.
FIG. 16 is aberration diagrams of the zoom lens system of Embodiment 3 when set at the wide-angle end and focused on an infinity object.
FIG. 17 is aberration diagrams of the zoom lens system of Embodiment 3 when set at an intermediate zoom position and focused on an infinity object.
FIG. 18 is aberration diagrams of the zoom lens system of Embodiment 3 when set at the telephoto end and focused on an infinity object.
FIG. 19 is aberration diagrams of the zoom lens system of Embodiment 3 when set at the wide-angle end and focused on an object at 500 mm (from the image plane).
FIG. 20 is aberration diagrams of the zoom lens system of Embodiment 3 when set at the intermediate zoom position and focused on an object at 500 mm (from the image plane).
FIG. 21 is aberration diagrams of the zoom lens system of Embodiment 3 when set at the telephoto end and focused on an object at 500 mm (from the image plane).
FIG. 22 is a sectional view of a zoom lens system of Embodiment 4.
FIG. 23 is aberration diagrams of the zoom lens system of Embodiment 4 when set at the wide-angle end and focused on an infinity object.
FIG. 24 is aberration diagrams of the zoom lens system of Embodiment 4 when set at an intermediate zoom position and focused on an infinity object.
FIG. 25 is aberration diagrams of the zoom lens system of Embodiment 4 when set at the telephoto end and focused on an infinity object.
FIG. 26 is aberration diagrams of the zoom lens system of Embodiment 4 when set at the wide-angle end and focused on an object at 500 mm (from the image plane).
FIG. 27 is aberration diagrams of the zoom lens system of Embodiment 4 when set at the intermediate zoom position and focused on an object at 500 mm (from the image plane).
FIG. 28 is aberration diagrams of the zoom lens system of Embodiment 4 when set at the telephoto end and focused on an object at 500 mm (from the image plane).
FIG. 29 is a sectional view of a zoom lens system of Embodiment 5.
FIG. 30 is aberration diagrams of the zoom lens system of Embodiment 5 when set at the wide-angle end and focused on an infinity object.
FIG. 31 is aberration diagrams of the zoom lens system of Embodiment 5 when set at an intermediate zoom position and focused on an infinity object.
FIG. 32 is aberration diagrams of the zoom lens system of Embodiment 5 when set at the telephoto end and focused on an infinity object.
FIG. 33 is aberration diagrams of the zoom lens system of Embodiment 5 when set at the wide-angle end and focused on an object at 500 mm (from the image plane).
FIG. 34 is aberration diagrams of the zoom lens system of Embodiment 5 when set at the intermediate zoom position and focused on an object at 500 mm (from the image plane).
FIG. 35 is aberration diagrams of the zoom lens system of Embodiment 5 when set at the telephoto end and focused on an object at 500 mm (from the image plane).
FIG. 36 is sectional views of a zoom lens system of Embodiment 6.
FIG. 37 is aberration diagrams of the zoom lens system of Embodiment 6 when set at the wide-angle end and focused on an infinity object.
FIG. 38 is aberration diagrams of the zoom lens system of Embodiment 6 when set at an intermediate zoom position and focused on an infinity object.
FIG. 39 is aberration diagrams of the zoom lens system of Embodiment 6 when set at the telephoto end and focused on an infinity object.
FIG. 40 is aberration diagrams of the zoom lens system of Embodiment 6 when set at the wide-angle end and focused on an object at 500 mm (from the image plane).
FIG. 41 is aberration diagrams of the zoom lens system of Embodiment 6 when set at the intermediate zoom position and focused on an object at 500 mm (from the image plane).
FIG. 42 is aberration diagrams of the zoom lens system of Embodiment 6 when set at the telephoto end and focused on an object at 500 mm (from the image plane).
FIG. 43 is a sectional view of a zoom lens system of Embodiment 7.
FIG. 44 is aberration diagrams of the zoom lens system of Embodiment 7 when set at the wide-angle end and focused on an infinity object.
FIG. 45 is aberration diagrams of the zoom lens system of Embodiment 7 when set at an intermediate zoom position and focused on an infinity object.
FIG. 46 is aberration diagrams of the zoom lens system of Embodiment 7 when set at the telephoto end and focused on an infinity object.
FIG. 47 is aberration diagrams of the zoom lens system of Embodiment 7 when set at the wide-angle end and focused on an object at 500 mm (from the image plane).
FIG. 48 is aberration diagrams of the zoom lens system of Embodiment 7 when set at the intermediate zoom position and focused on an object at 500 mm (from the image plane).
FIG. 49 is aberration diagrams of the zoom lens system of Embodiment 7 when set at the telephoto end and focused on an object at 500 mm (from the image plane).
FIG. 50 is a sectional view of a zoom lens system of Embodiment 8.
FIG. 51 is aberration diagrams of the zoom lens system of Embodiment 8 when set at the wide-angle end and focused on an infinity object.
FIG. 52 is aberration diagrams of the zoom lens system of Embodiment 8 when set at an intermediate zoom position and focused on an infinity object.
FIG. 53 is aberration diagrams of the zoom lens system of Embodiment 8 when set at the telephoto end and focused on an infinity object.
FIG. 54 is aberration diagrams of the zoom lens system of Embodiment 8 when set at the wide-angle end and focused on an object at 500 mm (from the image plane).
FIG. 55 is aberration diagrams of the zoom lens system of Embodiment 8 when set at the intermediate zoom position and focused on an object at 500 mm (from the image plane).
FIG. 56 is aberration diagrams of the zoom lens system of Embodiment 8 when set at the telephoto end and focused on an object at 500 mm (from the image plane).
FIG. 57 is a sectional view of a zoom lens system of Embodiment 9.
FIG. 58 is aberration diagrams of the zoom lens system of Embodiment 9 when set at the wide-angle end and focused on an infinity object.
FIG. 59 is aberration diagrams of the zoom lens system of Embodiment 9 when set at an intermediate zoom position and focused on an infinity object.
FIG. 60 is aberration diagrams of the zoom lens system of Embodiment 9 when set at the telephoto end and focused on an infinity object.
FIG. 61 is aberration diagrams of the zoom lens system of Embodiment 9 when set at the wide-angle end and focused on an object at 500 mm (from the image plane).
FIG. 62 is aberration diagrams of the zoom lens system of Embodiment 9 when set at the intermediate zoom position and focused on an object at 500 mm (from the image plane).
FIG. 63 is aberration diagrams of the zoom lens system of Embodiment 9 when set at the telephoto end and focused on an object at 500 mm (from the image plane).
FIG. 64 is a schematic view of the principal parts of a single-lens reflex camera.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of a zoom lens system and a camera using the zoom lens system shall now be described using the drawings.
FIG. 1 is a sectional view of a zoom lens of Embodiment 1. FIG. 2, FIG. 3, and FIG. 4 show aberration diagrams of the zoom lens of Embodiment 1 when focused on an infinity object while being set at the wide-angle end, an intermediate zoom position, and the telephoto end, respectively. FIG. 5, FIG. 6, and FIG. 7 show aberration diagrams of the zoom lens of Embodiment 1 when focused on an object at a distance (distance from an image plane) of 500 mm while being set at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, with the numerical values of numerical examples to be described below being expressed in units of mm.
FIG. 8 is a sectional view of a zoom lens of Embodiment 2. FIG. 9, FIG. 10, and FIG. 11 show aberration diagrams of the zoom lens of Embodiment 2 when focused on an infinity object while being set at the wide-angle end, an intermediate zoom position, and the telephoto end, respectively. FIG. 12, FIG. 13, and FIG. 14 show aberration diagrams of the zoom lens of Embodiment 2 when focused on an object at a distance (distance from the image plane) of 500 mm while being set at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, with the numerical values of numerical examples to be described below being expressed in units of mm.
FIG. 15 is a sectional view of a zoom lens of Embodiment 3. FIG. 16, FIG. 17, and FIG. 18 show aberration diagrams of the zoom lens of Embodiment 3 when focused on an infinity object while being set at the wide-angle end, an intermediate zoom position, and the telephoto end, respectively. FIG. 19, FIG. 20, and FIG. 21 show aberration diagrams of the zoom lens of Embodiment 3 when focused on an object at a distance (distance from the image plane) of 500 mm while being set at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, with the numerical values of numerical examples to be described below being expressed in units of mm.
FIG. 22 is a sectional view of a zoom lens of Embodiment 4. FIG. 23, FIG. 24, and FIG. 25 show aberration diagrams of the zoom lens of Embodiment 4 when focused on an infinity object while being set at the wide-angle end, an intermediate zoom position, and the telephoto end, respectively. FIG. 26, FIG. 27, and FIG. 28 show aberration diagrams of the zoom lens of Embodiment 4 when focused on an object at a distance (distance from the image plane) of 500 mm while being set at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, with the numerical values of numerical examples to be described below being expressed in units of mm.
FIG. 29 is a sectional view of a zoom lens of Embodiment 5. FIG. 30, FIG. 31, and FIG. 32 show aberration diagrams of the zoom lens of Embodiment 5 when focused on an infinity object while being set at the wide-angle end, an intermediate zoom position, and the telephoto end, respectively. FIG. 33, FIG. 34, and FIG. 35 show aberration diagrams of the zoom lens of Embodiment 5 when focused on an object at a distance (distance from the image plane) of 500 mm while being set at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, with the numerical values of numerical examples to be described below being expressed in units of mm.
FIG. 36 shows sectional views of a zoom lens of Embodiment 6, with (W) being the sectional view for the wide-angle end, (M) being that for an intermediate zoom position, and (T) being that for the telephoto end. FIG. 37, FIG. 38, and FIG. 39 show aberration diagrams of the zoom lens of Embodiment 6 when focused on an infinity object while being set at the wide-angle end, an intermediate zoom position, and the telephoto end, respectively. FIG. 40, FIG. 41, and FIG. 42 show aberration diagrams of the zoom lens of Embodiment 6 when focused on an object at a distance (distance from the image plane) of 500 mm while being set at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, with the numerical values of numerical examples to be described below being expressed in units of mm.
FIG. 43 is a sectional view of a zoom lens of Embodiment 7. FIG. 44, FIG. 45, and FIG. 46 show aberration diagrams of the zoom lens of Embodiment 7 when focused on an infinity object while being set at the wide-angle end, an intermediate zoom position, and the telephoto end, respectively. FIG. 47, FIG. 48, and FIG. 49 show aberration diagrams of the zoom lens of Embodiment 7 when focused on an object at a distance (distance from the image plane) of 500 mm while being set at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, with the numerical values of numerical examples to be described below being expressed in units of mm.
FIG. 50 is a sectional view of a zoom lens of Embodiment 8. FIG. 51, FIG. 52, and FIG. 53 show aberration diagrams of the zoom lens of Embodiment 8 when focused on an infinity object while being set at the wide-angle end, an intermediate zoom position, and the telephoto end, respectively. FIG. 54, FIG. 55, and FIG. 56 show aberration diagrams of the zoom lens of Embodiment 8 when focused on an object at a distance (distance from the image plane) of 500 mm while being set at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, with the numerical values of numerical examples to be described below being expressed in units of mm.
FIG. 57 is a sectional view of a zoom lens of Embodiment 9. FIG. 58, FIG. 59, and FIG. 60 show aberration diagrams of the zoom lens of Embodiment 9 when focused on an infinity object while being set at the wide-angle end, an intermediate zoom position, and the telephoto end, respectively. FIG. 61, FIG. 62, and FIG. 63 show aberration diagrams of the zoom lens of Embodiment 9 when focused on an object at a distance (distance from the image plane) of 500 mm while being set at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, with the numerical values of numerical examples to be described below being expressed in units of mm.
Each of Embodiments 1 through 9 comprises, in order from an object side, a front lens group FL which includes a plurality of lens units that moves along an optical axis during zooming, a negative refractive power lens unit BN that moves along the optical axis, and a positive refractive power lens unit BP that is not moved for zooming, and focusing from an infinity object to a close-distance object is performed by moving the abovementioned lens unit BN towards an image side.
The Embodiments 1 through 5, the sections of which are shown in FIG. 1, FIG. 8, FIG. 15, FIG. 22, and FIG. 29 shall be described first.
In each of FIG. 1, FIG. 8, FIG. 15, FIG. 22, and FIG. 29, L1 is a first lens unit with negative refractive power (optical power=reciprocal of the focal length), L2 is a second lens unit with positive refractive power, L3 is a third lens unit with negative refractive power, L4 is a fourth lens unit with positive refractive power, L5 is a fifth lens unit with negative refractive power, and L6 is a sixth lens unit with positive refractive power. With each of the zoom lens systems of the Embodiments 1 through 5, the front lens group FL is formed from the first to fourth lens units L1 to L4, the lens unit BN is constructed from the fifth lens unit L5, and the lens unit BP is constructed from the sixth lens unit L6.
SP is an aperture stop and SSP is an open F-number stop. IP is an image plane at which a photosensitive plane of an image pickup means (a solid-state image pickup element (photoelectric conversion element)), such as a CCD sensor, CMOS sensor, etc., or a silver halide film) is positioned. The aperture stop SP and the open F-number stop SSP move integrally with the third lens unit L3. The arrows in the figures indicate the movement loci of the lens units in zooming from the wide-angle end to the telephoto end.
With each of Embodiments 1 through 5, the first to fifth lens units L1 to L5 are moved so that in comparison to the wide-angle end, the spacing between the first lens unit L1 and the second lens unit L2 becomes smaller, the spacing between the second lens unit L2 and the third lens unit L3 becomes larger, the spacing between the third lens unit L3 and the fourth lens unit L4 becomes smaller, the spacing between the fourth lens unit L4 and the fifth lens unit L5 becomes larger, and the spacing between the fifth lens unit L5 and the sixth lens unit L6 becomes larger at the telephoto end. The sixth lens unit L6 is fixed with respect to the image plane IP.
Specifically, with each of the Embodiment 1, Embodiment 2, Embodiment 4, and Embodiment 5 of FIG. 1, FIG. 8, FIG. 22, and FIG. 29, in zooming from the wide-angle end to the telephoto end, the first lens unit L1 is moved towards the image side, the second lens unit L2 is moved towards the object side, the third lens unit L3 is moved along a part of a locus that is convex towards the object side, the fourth lens unit L4 is moved integrally with the second lens unit L2 towards the object side, and the fifth lens unit L5 is moved towards the object side.
With the Embodiment 3 of FIG. 15, the first lens unit L1 is moved towards the image side, the second lens unit L2 is moved towards the object side, the third lens unit L3 is moved towards the object side, the fourth lens unit L4 is moved integrally with the second lens unit L2 towards the object side, and the fifth lens unit L5 is moved towards the object side.
In each of Embodiments 1 through 5, the fifth lens unit L5 is moved towards the image side to perform focusing from an infinity object to a close-distance object. The wide-angle end and the telephoto end refer to zoom positions at which the lens units for zooming are positioned at the respective mechanical ends of the range in which the lens units are movable along the optical axis.
With each of the zoom lenses of the Embodiments 1 through 5, at the wide-angle end, the first lens unit L1 with negative refractive power becomes a front component with negative refractive power, and the second lens unit L2 and rearwards become a rear component with positive refractive power, thus providing a retro-focus type power configuration that is favorable for a wide angle lens.
Also at the telephoto end, the first lens unit L1 with negative refractive power and the second lens unit L2 with positive refractive power become a front component with positive refractive power as a whole and the third lens unit L3 and rearwards become a rear component with negative refractive power, thus providing a telephoto type power configuration that is favorable for a telescopic lens. Good optical performance can thus be provided readily from the wide-angle end to the telephoto end zoom positions and brightness (small F number) can be secured readily especially at the telephoto side.
Also by making the spacing between the fourth lens unit L4 and the fifth lens unit L5 become larger in zooming from the wide-angle end to the telephoto end, the variation of an image plane that accompanies the zooming can be corrected more readily, and by making the spacing between the fifth lens unit L5 and the sixth lens unit L6 become larger, the distance from the optical axis to the off-axial rays that are made incident on the sixth lens unit L6 is made greater to enable the positive distortion that occurs at the second lens unit L2 to be corrected more readily.
Generally with a lens unit that makes up an optical system, in the case where the effective ray diameter is determined by the off-axial rays, the greater the angle (with the positive direction being the counterclockwise direction from the optical axis) formed by the optical axis and the off-axial rays that are made incident onto the lens unit, the greater the variation of the effective ray diameter that occurs when the aperture and the distance change. With each of Embodiments 1 through 5, since the off-axial rays that are made incident on the fifth lens unit L5 is refracted by the fourth lens unit L4 with positive refractive power so that the angle formed by the optical axis and the off-axial rays will be small, the variation of the effective ray diameter that accompanies the movement is small. Thus the fifth lens unit L5 is used as a focusing lens unit and reduction of the lens diameter is achieved.
The fifth lens unit L5 for focusing comprises a positive lens and a negative lens. The aberration variations that occur during focusing are thereby made small. Also, the sixth lens unit L6, which is unmoved for zooming, comprises a single positive lens.
By making the second lens unit L2 move towards the object side in zooming from the wide-angle end to the telephoto end, the realization of a telephoto type power configuration at the telephoto end is facilitated, the setting of an appropriate telephoto ratio at the telephoto end is facilitated, and the correction of the spherical aberration and the curvature of field at the telephoto end is facilitated in particular. Also by making the fourth lens unit L4 move towards the object side, the positioning of the fifth lens unit L5 and the sixth lens unit L6 at positions away from the image plane at the telephoto end is facilitated and consequently, the securing of back focal distance at the telephoto end is facilitated.
The second lens unit L2 and the fourth lens unit L4 are moved integrally in zooming, thereby enabling simplification of the lens barrel structure.
By moving the fifth lens unit L5 towards the object side in zooming from the wide-angle end to the telephoto end, the positioning of the sixth lens unit L6 at a position away from the image plane at the telephoto end is facilitated and consequently, the securing of back focal distance at the telephoto end is facilitated.
With each of Embodiments 1 through 5:

    
    
        The second lens unit L2 preferably comprises at least one negative lens and at least one positive lens. The correction of axial chromatic aberration at the telephoto end is thereby facilitated.
    
    


The sixth lens unit L6 preferably has an aspherical surface of a shape with which a positive refractive power increases from the optical axis towards the lens periphery. The correction of positive distortion at the telephoto end is thereby facilitated.
The fifth lens unit L5 preferably comprises at least one negative lens and at least one positive lens. The variation of the chromatic aberration of magnification that accompanies zooming can thereby be restrained readily.
With each of Embodiments 1 through 5, in a case where a lens surface is to be made an aspherical surface, an aspherical surface layer of resin, etc. may be formed on the surface of a spherical lens as long as the aspherical surface is positioned at a part besides the surface at the most object side and the surface at the most image side of the lens system.
With each of Embodiments 1 through 5, when β5t is the lateral magnification at the telephoto end of the fifth lens unit L5, βrt is the lateral magnification at the telephoto end of the lens unit positioned to the image side of the fifth lens unit L5, fi is the focal length of the abovementioned i-th lens unit, fw is the focal length of the overall optical system at the wide-angle end, and ft is the focal length of the overall optical system at the telephoto end, one or more the following Conditional Expressions is or are satisfied.

1.1<|(1−β5t2)×βrt2|  (1)

0.2<|f5/√{square root over ((fw×ft)}|<4.0  (2)

0.5<f6/√{square root over (fw×ft)}<10.0  (3)

0.8<|f1/fw|<2.3  (4)

0.1<f2/ft<2.0  (5)

0.5<|f3/fw|<4.5  (6)

0.3<f4/ft<2.0  (7)

0.2<|f5/ft|<1.9  (8)

1.0<f6/fw<8.0  (9)

Each of Embodiments 1 through 5 do not have to satisfy all of the Conditional Expressions (1) to (9) at the same time necessarily and may satisfy one or more of the Conditional Expressions and each effect that is in accordance with the satisfied Conditional Expression is thereby obtained.
The technical significance of the abovementioned Conditional Expressions (1) through (9) shall now be described.
The Conditional Expression (1) is for making the fifth lens unit L5 favorable as a focusing lens unit. By satisfying this Conditional Expression (1), an adequate focus sensitivity (focal point movement amount per movement amount of the focusing lens unit) can be secured for the fifth lens unit L5 at the telephoto end, thus enabling the focusing movement amount of the fifth lens unit L5 to be made small and thereby enabling the entire optical system to be made compact.
The Conditional Expression (2) is for setting the focal length of the fifth lens unit L5 appropriately.
By setting within the upper limit of the Conditional Expression (2), the canceling out of the negative distortion that occurs at the first lens unit L1 with negative refractive power at the wide-angle end is facilitated in particular, and by setting within the lower limit of the Conditional Expression (2), the distance from the optical axis of the off-axial rays that are made incident on the sixth lens unit L6 at the telephoto end can be made small, thereby enabling the effective lens diameter of the sixth lens unit L6 to be made small appropriately.
The Conditional Expression (3) is for setting the focal length of the sixth lens unit L6 appropriately.
By setting within the upper limit of the Conditional Expression (3), the securing of back focal distance at the wide-angle end is facilitated in particular and by setting within the lower limit of the Conditional Expression (3), the negative distortion at the wide-angle end can be corrected well readily.
The Conditional Expression (4) is for setting the focal length of the first lens unit L1 with negative refractive power appropriately. By satisfying the Conditional Expression (4), the correction of the negative distortion at the wide-angle end and the making of the front diameter small can be achieved readily at the same time.
The Conditional Expression (5) is for setting the focal length of the second lens unit L2 with positive refractive power appropriately. By satisfying the Conditional Expression (5), the correction of the spherical aberration and the securing of a bright F number at the telephoto end can be achieved readily at the same time.
The Conditional Expression (6) is for setting the focal length of the third lens unit L3 with negative refractive power appropriately. By satisfying the Conditional Expression (6), the securing of a bright F number at the telephoto end and the correction of the coma aberration and distortion of the entire focal length range can be achieved readily at the same time.
The Conditional Expression (7) is for setting the focal length of the fourth lens unit L4 with positive refractive power appropriately. By satisfying the Conditional Expression (7), the securing of the zoom ratio and the correction of the negative distortion at the wide-angle end can be achieved readily at the same time.
The Conditional Expression (8) is for setting the focal length of the fifth lens unit L5 with negative refractive power appropriately. By satisfying the Conditional Expression (8), the variation of distortion that accompanies zooming can be restrained readily.
The Conditional Expression (9) is for setting the focal length of the sixth lens unit L6 with positive refractive power appropriately. By satisfying the Conditional Expression (9), the securing of back focal distance at the wide-angle end and the making of the rear diameter small can be achieved readily at the same time.
With each of Embodiments 1 through 5, in order to maintain even better optical performance, the numerical ranges of the Conditional Expression (1) through (9) are preferably set as follows:

1.3<|(1−β5t2)×βrt2|  (1a)

0.5<|f5/√{square root over ((fw×ft)}|<3.0  (2a)

1.0<f6/√{square root over (fw×ft)}<4.0  (3a)

1.0<|f1/fw|<2.0  (4a)

0.3<f2/ft<1.3  (5a)

1.5<|f3/fw|<3.5  (6a)

0.4<f4/ft<1.4  (7a)

0.4<|f5/ft|<1.7  (8a)

2.0<f6/fw<6.0  (9a)

As has been described above, with each of Embodiments 1 through 5, a wide-angle zoom lens, which covers a wide-angle region, has a zoom ratio of 2 times or more, has a large aperture of an F number of approximately 2.8, and yet exhibits good optical performance, is realized.
Embodiments 6 through 9 of FIG. 36, FIG. 43, FIG. 50, and FIG. 57 shall now be described.
In each of the lens sections of Embodiments 6 through 9 shown in FIG. 36, FIG. 43, FIG. 50, and FIG. 57, L1 is a first lens unit with positive refractive power, L2 is a second lens unit with negative refractive power, and BR is a rear lens group with positive refractive power.
SP is an aperture stop and IP is an image plane at which a photosensitive plane of an image pickup means (a solid-state image pickup element or a silver halide film) is positioned. Rear lens group BR comprises, in order from an object side, one or more lens units BRX (third to fifth lens units), a lens unit BRa (sixth lens unit) with negative refractive power, and a lens unit BRb (seventh lens unit) with positive refractive power.
The lens units BRX comprises, in order from the object side, a lens unit BR1 (third lens unit) with positive refractive power, a lens unit BR2 (fourth lens unit) with negative refractive power, and a lens unit BR3 (fifth lens unit) with positive refractive power. The arrows in the figures indicate the movement loci of the lens units in zooming from the wide-angle end to the telephoto end. The first lens unit L1, the second lens unit L2, and the lens units BR1 to BR3 constitute a front lens group.
With Embodiments 6 through 9, zooming is performed by moving the lens units so that in comparison to the wide-angle end, the spacing between the first lens unit L1 and the second lens unit L2 becomes larger and the spacing between the second lens unit L2 and the rear lens group BR becomes smaller at the telephoto end.
More specifically, in zooming from the wide-angle end to the telephoto end, the first lens unit L1 is moved towards the object side, the second lens unit L2 is moved towards an image side, the lens unit BR1 (third lens unit) is moved towards the object side so that the spacing with respect to the second lens unit L2 becomes larger, the lens unit BR2 (fourth lens unit) is moved towards the object side so that spacing with respect to the lens unit BR1 (third lens unit) becomes smaller, the lens unit BR3 (fifth lens unit) is moved integrally with the lens unit BR1 (third lens unit) towards the object side so that the spacing with respect to the lens unit BR2 (fourth lens unit) becomes smaller, and the lens unit BRa (sixth lens unit) is moved towards the object side while changing in the spacing with respect to the lens unit BR3 (fifth lens unit).
For zooming, the lens unit BRb (seventh lens unit) is fixed with respect to the image plane IP. The aperture stop SP moves integrally with the lens unit BR1 during zooming. Also, focusing from an infinity object to a close-distance object is performed by moving the lens unit BRa towards the image side.
Generally when a lens unit with positive refractive power is positioned at the image side of an optical system, the position of the image-side principal point of the optical system moves towards the image side, thereby facilitating the securing of back focal distance. Oppositely, when a lens unit with negative refractive power is positioned at the image side of an optical system, the position of the image-side principal point of the optical system moves towards the object side and the back focal distance tends to be short.
With the focal distancing lens unit BRa in each of the zoom lenses of Embodiments 6 through 9, even though the negative refractive power of the focusing lens unit is strengthened to make the focusing movement amount small, by positioning the lens unit BRb with positive refractive power at the image side, the securing of back focal distance is facilitated and an advantage is provided in realizing a wider view angle at the wide-angle end.
In particular, the focusing lens unit BRa comprises a negative lens, a positive lens, and a negative lens. The aberration variations that occur during focusing are thus lessened. Also, the lens unit BRb, which is unmoved for zooming, comprises a single positive lens.
Furthermore with each of Embodiments 6 through 9, in zooming from the wide-angle side to the telephoto side, the spacing between the lens unit RBa and the lens unit RBb is made larger to facilitate the securing of movement space for the focusing lens unit even at the telephoto side at which the amount of movement of the image plane in accompaniment with the variation of the object distance is large.
In particular, by moving the lens unit BRa to the object side in zooming from the wide-angle end to the telephoto end, the positioning of the lens unit BRb at a position away from the image plane at the telephoto end is facilitated and consequently, the securing of back focal distance at the telephoto end is facilitated.
Also, an aspherical surface is preferably used in order to maintain high optical performance. As an aspherical surface to be used here, an aspherical surface layer of resin, etc. may be formed on the surface of a spherical lens as long as the aspherical surface is positioned at a part besides the surface at the most object side and the surface at the most image side of the lens system.
With each of Embodiments 6 through 9, when βBRat is the lateral magnification at the telephoto end of the lens unit BRa, βBRbt is the lateral magnification at the telephoto end of the lens unit BRb, fBRa is the focal length of the lens unit BRa, fBRb is the focal length of the lens unit BRb, fw is the focal length of the overall optical system at the wide-angle end, ft is the focal length of the overall optical system at the telephoto end, fi is the focal length of the abovementioned i-th lens unit, fBRi is the focal length of the lens unit BRi, the lens unit BRa has at least one positive lens, and νp is the Abbe's number of the material of the positive lens inside the lens unit BRa (the average value in a case where there are a plurality of positive lenses), one or more the following Conditional Expressions is or are satisfied.

3.0<|(1−βBRat2)×βBRbt2|  (10)

0.1<|fBRa/√{square root over ((fw×ft))}|<0.9  (11)

1.0<fBRb/√{square root over ((fw×ft))}<10.0  (12)

νp<45  (13)

1.0<f1/√{square root over ((fw×ft))}<3.0  (14)

0.1<|f2|/√{square root over ((fw×ft))}<0.5  (15)

0.2<fBR1/√{square root over ((fw×ft))}<0.8  (16)

0.3<|fBR2/√{square root over ((fw×ft))}<1.0  (17)

0.2<fBR3/√{square root over ((fw×ft))}<1.0  (18)

Each of Embodiments 6 through 9 do not have to satisfy all of the Conditional Expressions (10) to (18) at the same time necessarily and may satisfy one or more of the Conditional Expressions, and each effect that is in accordance with the satisfied Conditional Expression is thereby obtained.
The technical significance of the abovementioned Conditional Expressions (10) through (18) shall now be described.
The Conditional Expression (10) is for making the lens unit BRa favorable as a focusing lens unit. By satisfying this Conditional Expression (10), an adequate focus sensitivity (focal point movement amount per movement amount of the focusing lens unit) can be secured for the lens unit BRa at the telephoto end, thus enabling the focusing movement amount of the lens unit BRa to be made small and thereby enabling the entire optical system to be made compact.
The Conditional Expression (11) is for setting the focal length of the lens unit BRa appropriately.
By setting within the upper limit of the Conditional Expression (11), the canceling out of the negative distortion that occurs at the second lens unit L2 with negative refractive power at the wide-angle end is facilitated in particular, and by setting within the lower limit of the Conditional Expression (11), the distance from the optical axis of the off-axial rays that are made incident on the lens unit BRb at the telephoto end can be made small, thereby enabling the effective lens diameter of the lens unit BRb to be set appropriately.
The Conditional Expression (12) is for setting the focal length of the lens unit BRb.
By setting within the upper limit of the Conditional Expression (12), the securing of back focal distance at the wide-angle end is facilitated in particular and by setting within the lower limit of the Conditional Expression (12), the negative distortion at the wide-angle end can be corrected readily.
When the Conditional Expression (13) is satisfied, the variation of the chromatic aberration of magnification that accompanies zooming can be restrained more readily.
The Conditional Expression (14) is for setting the focal length of the first lens unit L1. When the upper limit of the Conditional Expression (14) is exceeded, an adequate telephoto type lens system cannot be realized at the telephoto side and the securing of a bright F number becomes difficult. Below the lower limit of the Conditional Expression (14), the front lens diameter will then to be large and unfavorable.
The Conditional Expression (15) is for setting the focal length of the second lens unit L2. Below the lower limit of the Conditional Expression (15), the correction of the negative distortion becomes difficult especially at the wide-angle side, and when the upper limit of the Conditional Expression (15) is exceeded, the securing of an adequate zoom ratio becomes difficult.
The Conditional Expression (16) is for setting the focal length of the lens unit BR1 appropriately. By satisfying the Conditional Expression (16), the aberrations that occur at the lens unit BR1 can be corrected readily in a well-balanced manner by the other lens units and a high zoom ratio can be realized readily.
The Conditional Expression (17) is for setting the focal length of the lens unit BR2 appropriately. By satisfying the Conditional Expression (17), the securing of the zoom ratio and the correction of the flare that is occurred by upper rays of the off-axial rays in the intermediate zoom region are facilitated further.
The Conditional Expression (18) is for setting the focal length of the lens unit BR3 appropriately. By satisfying the Conditional Expression (18), the securing of the zoom ratio and the correction of the negative distortion at the wide-angle end can be achieved readily at the same time.
With each of Embodiments 6 through 9, in order to maintain even better optical performance, the numerical ranges of the Conditional Expressions (10) through (18) are preferably set as follows:

5.0<|(1−βBRat2)×βBRbt2|  (10a)

0.25<|fBRa/√{square root over ((fw×ft))}|<0.7  (11a)

2.0<fBRb/√{square root over ((fw×ft))}<7.0  (12a)

νp<40  (13a)

1.15<f1/√{square root over (fw×ft)}<2.5  (14a)

0.15<|f2|/√{square root over ((fw×ft))}<0.3  (15a)

0.3<fBR1/√{square root over ((fw×ft))}<0.6  (16a)

0.4<|fBR2|/√{square root over ((fw×ft))}<0.75  (17a)

0.3<fBR3/√{square root over ((fw×ft))}<0.6  (18a)

As has been described above, with Embodiments 6 through 9, a focusing system and a zoom lens employing the same, which cover a wide-angle region, have a zoom ratio of approximately 10 times, and enable the shortening of the close-distance image taking distance without degradation of good optical performance, can be realized readily.
An embodiment of a single-lens reflex camera that employs a zoom lens according to one of Embodiments 1 to 9 shall now be described with reference to FIG. 64. In FIG. 64, Reference numeral 10 shows a main single-lens reflex camera body, 11 shows an interchangeable lens incorporating a zoom lens according to one of Embodiments 1 to 9. Reference numeral 12 shows a photosensitive plane of a silver halide film, a solid-state image pickup element (photoelectric conversion element), or the like for recording an object image obtained through the interchangeable lens 11. Reference numeral 13 shows a viewfinder optical system for observing the object image from the interchangeable lens 11, and 14 shows a quick-return mirror that rotates to transmit the object image from the interchangeable lens 11 interchangingly to the photosensitive plane 12 and the viewfinder optical system 13. For observation of the object image via the viewfinder, the object image that is formed on a focus plate 15 via the quick-return mirror 14 is made an erect image by a pentaprism 16 and thereafter observed upon magnification by an ocular optical system 17. For image taking, the quick-return mirror 14 is rotated in the direction of the arrow and the object image is formed on the photosensitive plane 12 and recorded.
By thus applying the zoom lens according to Embodiments to an optical apparatus, such as an interchangeable lens for single-lens reflex camera, an optical apparatus of high optical performance can be realized.
The present invention can also be applied to a single-lens reflex camera without a quick-return mirror.
Numerical Examples 1 to 9, corresponding to Embodiment 1 to Embodiment 9, respectively, of the present invention shall now be described. With Numerical Examples, i indicates the order of a surface from the object side, Ri indicates the radius of curvature of each surface, Di indicates the thickness or air spacing between the i-th and (i+1)-th optical members, and Ni and vi are the refractive index and Abbe's number for d-line, respectively, of the i-th optical member.
Also, with R being the radius of curvature of the central part of a surface, X being the displacement in the optical axis direction (traveling direction of light) at a position of height Y from the optical axis and with the surface apex being the reference point, and A, B, C, D, E, and F being aspherical coefficients, each aspherical surface is expressed by:




  X
  =
  
    
      
        
          (
          
            1
            /
            R
          
          )
        
        ⁢
        
          Y
          2
        
      
      
        1
        +
        
          
            1
            -
            
              
                (
                
                  Y
                  /
                  R
                
                )
              
              2
            
          
        
      
    
    +
    
      AY
      2
    
    +
    
      BY
      4
    
    +
    
      CY
      6
    
    +
    
      DY
      8
    
    +
    
      EY
      10
    
    +
    
      FY
      12
    
  




[e−x] expresses [×10−x]. Also, the relationships between a part of the respective Conditional Expressions given above and the various numerical values of Numerical Examples are shown Tables 1 and 2.










Numerical example 1


f = 24.70~67.98 Fno = 2.92~3.25 2ω = 82.4~35.3


















‡ R1 = 161.044
D1 = 2.50
N1 = 1.772499
ν1 = 49.5


 R2 = 34.883
D2 = 12.15


 R3 = −164.700
D3 = 2.30
N2 = 1.772499
ν2 = 49.6


 R4 = 67.311
D4 = 0.15


 R5 = 63.340
D5 = 5.04
N3 = 1.805181
ν3 = 25.4


 R6 = 182.601
D6 = Variable


 R7 = 685.874
D7 = 1.90
N4 = 1.805181
ν4 = 25.4


 R8 = 51.916
D8 = 6.23
N5 = 1.772499
ν5 = 49.6


 R9 = −127.867
D9 = 0.15


 R10 = 91.053
D10 = 3.83
N6 = 1.834807
ν6 = 42.7


 R11 = −656.456
D11 = 0.15


 R12 = 44.736
D12 = 4.99
N7 = 1.696797
ν7 = 55.5


 R13 = 580.418
D13 = Variable


 R14 = Stop
D14 = 2.21


 R15 = −127.874
D15 = 1.30
N8 = 1.882997
ν8 = 40.8


 R16 = 44.148
D16 = 2.56


 R17 = −104.764
D17 = 1.30
N9 = 1.719995
ν9 = 50.2


 R18 = 33.858
D18 = 4.94
N10 = 1.805181
ν10 = 25.4


 R19 = −110.923
D19 = 0.69


 R20 = Stop
D20 = Variable


 R21 = 122.859
D21 = 1.30
N11 = 1.846660
ν11 = 23.9


 R22 = 26.169
D22 = 6.42
N12 = 1.496999
ν12 = 81.5


 R23 = −52.096
D23 = 0.15


 R24 = 34.003
D24 = 4.55
N13 = 1.651597
ν13 = 58.5


 R25 = −138.004
D25 = Variable


 R26 = 326.115
D26 = 3.09
N14 = 1.846660
ν14 = 23.9


 R27 = −47.848
D27 = 0.15


 R28 = −51.140
D28 = 1.20
N15 = 1.834000
ν15 = 37.2


 R29 = 26.555
D29 = Variable


 R30 = 63.856
D30 = 7.59
N16 = 1.583126
ν16 = 59.4


‡ R31 = −98.162













Variable
Focal length












spacing
24.70
35.00
67.98







D6 
55.58
31.43
3.13



D13
2.90
6.40
19.82



D20
18.67
15.17
1.74



D25
1.19
3.49
10.67



D29
4.82
10.93
15.06











Aspheric coefficient










Surface 1:
A = 0.0000e+00 B = 1.19663e−10




C = 4.70286e=10 D = 1.28360e−12




E = 1.21542e−15 F = 4.19913e−19



Surface 31:
A = −0.0000e+00 B = −1.86742e−07




C = −9.96565e−09 D = 6.00710e−11




E = −1.90097e−13  F = 2.27739e−16






















Numerical example 2


f = 22.70~58.38 Fno = 2.90~3.26 2ω = 87.3~40.7













‡ R1 = 123.605
D1 = 2.50
N1 = 1.772499
ν1 = 49.6


 R2 = 29.825
D2 = 13.13


 R3 = −106.694
D3 = 2.30
N2 = 1.772499
ν2 = 49.5


 R4 = 82.370
D4 = 3.00


 R5 = 92.868
D5 = 4.00
N3 = 1.805181
ν3 = 25.4


 R6 = 437.552
D6 = Variable


 R7 = 410.770
D7 = 1.90
N4 = 1.805181
ν4 = 25.4


 R8 = 52.875
D8 = 6.03
N5 = 1.717004
ν5 = 47.9


 R9 = −119.460
D9 = 0.15


 R10 = 86.807
D10 = 3.57
N6 = 1.834807
ν6 = 42.7


 R11 = −647.303
D11 = 0.15


 R12 = 47.266
D12 = 4.51
N7 = 1.696797
ν7 = 55.5


 R13 = 505.161
D13 = Variable


 R14 = Stop
D14 = 2.13


 R15 = −151.295
D15 = 1.30
N8 = 1.882997
ν8 = 40.8


 R16 = 49.052
D16 = 1.95


 R17 = −303.974
D17 = 2.72
N9 = 1.799516
ν9 = 42.2


 R18 = 37.202
D18 = 3.91
N10 = 1.846660
ν10 = 23.9


 R19 = −187.667
D19 = 0.98


 R20 = Stop
D20 = Variable


 R21 = 126.439
D21 = 1.30
N11 = 1.846660
ν11 = 23.9


 R22 = 26.548
D22 = 6.83
N12 = 1.496999
ν12 = 81.5


 R23 = −51.005
D23 = 0.15


 R24 = 32.556
D24 = 4.69
N13 = 1.617722
ν13 = 49.8


 R25 = −132.456
D25 = Variable


 R26 = −204.803
D26 = 2.68
N14 = 1.846660
ν14 = 23.9


 R27 = −41.551
D27 = 0.15


 R28 = −46.661
D28 = 1.20
N15 = 1.834000
ν15 = 37.2


 R29 = 28.810
D29 = Variable


 R30 = 67.617
D30 = 8.05
N16 = 1.583126
ν16 = 59.4


‡ R31 = −68.737













Variable
Focal length












spacing
22.70
35.00
58.38







D6 
49.50
21.29
1.50



D13
2.88
8.24
20.31



D20
19.19
13.83
1.77



D25
1.19
4.99
11.75



D29
4.00
10.46
13.67











Aspheric coefficent










Surface 1:
A = 0.00000e+00 B = 2.04437e−06




C = 6.895383−10 D = 2.46407e−18




E = 70925e−15 F = −1.00883e−18



Surface 31:
A = −0.00000e+00 B = 1.97079e−06 




C = −1.94774e−10 D = 1.27725e−10




E = −3.19694e−13 F = 3.51352e−16






















Numerical example 3


f = 20.60~48.58 Fno = 2.90~3.35 2ω= 92.8~48.0













‡ R1 = 134.542
D1 = 2.50
N1 = 1.772499
ν1 = 49.6


 R2 = 27.188
D2 = 13.78


 R3 = −78.185
D3 = 2.30
N2 = 1.834807
ν2 = 42.7


 R4 = 97.239
D4 = 3.00


 R5 = 229.018
D5 = 4.62
N3 = 1.805181
ν3 = 25.4


 R6 = −119.495
D6 = Variable


 R7 = 274.749
D7 = 2.80
N4 = 1.516330
ν4 = 64.1


 R8 = −122.916
D8 = 0.15


 R9 = 108.113
D9 = 1.90
N5 = 1.751821
ν5 = 26.5


 R10 = 37.302
D10 = 6.06
N6 = 1.517417
ν6 = 62.4


 R11 = −153.717
D11 = 0.15


 R12 = 37.916
D12 = 4.28
N7 = 1.834807
ν7 = 42.7


 R13 = 827.789
D13 = Variable


 R14 = Stop
D14 = 2.15


 R15 = −150.776
D15 = 1.30
N8 = 1.882997
ν8 = 40.8


 R16 = 56.320
D16 = 2.96


 R17 = −249.978
D17 = 1.25
N9 = 1.834807
ν9 = 42.7


 R18 = 28.355
D18 = 5.54
N10 = 1.805181
ν10 = 25.4


 R19 = −111.253
D19 = 0.70


 R20 = Stop
D20 = Variable


 R21 = 298.278
D21 = 1.30
N11 = 1.846660
ν11 = 23.9


 R22 = 25.523
D22 = 6.76
N12 = 1.496999
ν12 = 81.5


 R23 = −53.374
D23 = 0.15


 R24 = 36.174
D24 = 4.63
N13 = 1.712995
ν13 = 53.9


 R25 = −106.296
D25 = Variable


 R26 = −70.596
D26 = 1.84
N14 = 1.846660
ν14 = 23.9


 R27 = −46.779
D27 = 0.15


 R28 = −87.418
D28 = 1.20
N15 = 1.834807
ν15 = 42.7


 R29 = 29.748
D29 = Variable


 R30 = 56.914
D30 = 8.04
N16 = 1.583126
ν16 = 59.4


‡ R31 = −79.720













Variable
Focal length












spacing
20.60
27.94
48.58







D6 
51.99
28.30
1.50



D13
2.74
4.33
12.95



D20
12.34
10.75
2.13



D25
1.19
4.88
12.68



D29
3.15
8.17
12.97











Aspheric coefficent










Surface 1:
A = 00000e+00 B = 3.71994e−08




C = 1.14775e−09 D = −2.5363e−13




E = 1.29688e−15 F = −6.25550e−19



Surface 31:
A = −0.00000e+00 B = 3.33792e−06




C = −2.38616e−08 D = 1.41155e−10




E = 3.97666e−13 F = 4.30136e−16






















Numerical example 4


f = 17.50~38.64 Fno = 2.90~3.47 2ω = 102.1~58.5













‡ R1 = 170.715
D1 = 2.50
N1 = 1.772499
ν1 = 49.6


 R2 = 20.601
D2 = 14.51


 R3 = −53.500
D3 = 2.30
N2 = 1.804000
ν2 = 46.6


 R4 = 607.412
D4 = 1.67


 R5 = 81.370
D5 = 2.82
N3 = 1.805181
ν3 = 25.4


‡ R6 = 526.843
D6 = Variable


 R7 = 96.443
D7 = 4.17
N4 = 1.582673
ν4 = 46.4


 R8 = −567.926
D8 = 0.15


 R9 = 55.537
D9 = 1.90
N5 = 1.761821
ν5 = 26.5


 R10 = 20.113
D10 = 7.34
N6 = 1.517417
ν6 = 52.4


 R11 = −128.843
D11 = 0.15


 R12 = 49.324
D12 = 4.18
N7 = 1.651597
ν7 = 58.5


 R13 = −284.150
D13 = Variable


 R14 = Stop
D14 = 2.34


 R15 = −88.745
D15 = 1.30
N8 = 1.882997
ν8 = 40.8


 R16 = 69.569
D16 = 1.13


 R17 = −2084.655
D17 = 1.25
N9 = 1.882997
ν9 = 40.8


 R18 = 23.480
D18 = 8.64
N10 = 1.805181
ν10 = 25.4


 R19 = −155.701
D19 = 0.95


 R20 = Stop
D20 = Variable


 R21 = 141.268
D21 = 1.30
N11 = 1.846660
ν11 = 23.9


 R22 = 29.443
D22 = 6.93
N12 = 1.495999
ν12 = 81.5


 R23 = −58.983
D23 = 0.15


 R24 = 39.554
D24 = 6.32
N13 = 1.589130
ν13 = 61.1


 R25 = −85.186
D25 = Variable


 R26 = −73.538
D26 = 1.85
N14 = 1.846660
ν14 = 23.9


 R27 = −56.343
D27 = 0.15


 R28 = 214.109
D28 = 1.20
N15 = 1.834807
ν15 = 42.7


‡ R29 = 32.563
D29 = Variable


 R30 = 46.730
D30 = 7.13
N16 = 1.487490
ν16 = 70.2


 R31 = −196.608













Variable
Focal length












spacing
17.50
24.00
38.64







D6 
35.21
19.54
5.00



D13
2.21
5.64
17.21



D20
16.94
13.51
1.94



D25
1.18
5.61
14.79



D29
2.27
8.77
9.63











Aspheric coefficient










Surface 1:
A = 0.00000e+00 B = 1.05853e−06




C = 4.31049e−09 D = 5.72891e−12




E = 1.84562e−17 F = 7.13953e−19



surface 6:
A = 0.00000e+00 B = 3.13215e−06




C = 2.14047e−09 D = 1.36230e−11




E = 4.18879e−14 F = 3.14497e−17



Surface 29:
A = 0.00000e+00 B = 3.14396e−06




C = 1.97029e−08 D = 1.89008e−10




E = 7.33403e−13 F = 1.08139e−15






















Numerical example 5


f = 15.45~33.98 Fno = 2.90~3.33 2ω = 108.9~65.0













‡ R1 = 92.533
D1 = 2.50
N1 = 1.772499
ν1 = 49.6


 R2 = 23.411
D2 = 21.77


 R3 = −95.356
D3 = 2.30
N2 = 1.804000
ν2 = 46.6


 R4 = 93.439
D4 = 3.00


 R5 = 69.502
D5 = 3.73
N3 = 1.846660
ν3 = 23.9


‡ R6 = 160.973
D6 = Variable


 R7 = −397.286
D7 = 3.20
N4 = 1.617722
ν4 = 49.8


 R8 = −198.878
D8 = 0.15


 R9 = 62.345
D9 = 1.90
N5 = 1.761821
ν5 = 26.5


 R10 = 30.395
D10 = 6.94
N6 = 1.517417
ν6 = 52.4


 R11 = −83.804
D11 = 0.15


 R12 = 43.966
D12 = 4.05
N7 = 1.677900
ν7 = 55.3


 R13 = −216.458
D13 = Variable


 R14 = Stop
D14 = 2.21


 R15 = 164.995
D15 = 1.30
N8 = 1.882997
ν8 = 40.8


 R16 = 88.797
D16 = 3.36


 R17 = −72.757
D17 = 1.25
N9 = 1.882997
ν9 = 40.8


 R18 = 22.478
D18 = 8.60
N10 = 1.805181
ν10 = 25.4


 R19 = −96.860
D19 = 2.30


 R20 = Stop
D20 = Variable


 R21 = 120.586
D21 = 1.30
N11 = 1.846660
ν11 = 23.9


 R22 = 31.305
D22 = 7.43
N12 = 1.496999
ν12 = 81.5


 R23 = −42.078
D23 = 0.15


 R24 = 38.952
D24 = 5.95
N13 = 1.516330
ν13 = 64.1


‡ R25 = −110.475
D25 = Variable


 R26 = −59.043
D26 = 1.44
N14 = 1.846660
ν14 = 23.9


 R27 = −55.437
D27 = 0.15


 R28 = 238.252
D28 = 1.20
N15 = 1.834807
ν15 = 42.7


‡ R29 = 30.403
D29 = Variable


 R30 = 36.986
D30 = 4.95
N16 = 1.583126
ν16 = 59.4


‡ R31 = 552.279













Variable
Focal length












spacing
15.45
20.00
33.98







D6 
50.29
25.99
5.03



D13
2.30
1.80
12.99



D20
15.01
15.50
4.32



D25
1.50
7.83
13.86



D29
1.50
2.81
4.52











Aspheric coefficient










Surface 1:
A = 0.00000e+00 B = 4.67142e−06




C = 1.41100e−09 D = 8.75148e−13




E = 1.60628e−16 F = 2.51806e−20



Surface 6:
A = 0.00000e+00 B = 1.49406e−06




C = −6.31444e+09 D = 2.34297e−11




E = −4.91178e−14 F = 3.59501e−17



Surface 25:
A = 0.00000e+00 B = −7.73118e−07




C = 7.26783e−11 D = −2.27820e−11




E = 8.09270e−14 F = −9.97880e−17



Surface 29:
A = 0.00000e+00 B = −1.24689e−06




C = −4.32541e−09 D = 3.51094e−11




E = −2.59044e−14 F = −1.50164e−16



Surface 31:
A = −0.00000e+00 B = 5.84931e−06




C = −3.10476e−08 D = 3.51094e−10




E = −9.53206e−13 F = 1.33118e−15






















Numerical example 6


f = 28.80~339.99 Fno = 3.59~5.66 2ω = 73.8~7.3













 R1 = 119.245
D1 = 3.00
N1 = 1.834000
ν1 = 37.2


 R2 = 69.427
D2 = 8.31
N2 = 1.496999
ν2 = 81.6


 R3 = 2874.028
D3 = 0.16


 R4 = 81.906
D4 = 6.94
N3 = 1.496999
ν3 = 81.6


 R5 = 1880.891
D5 = Variable


 R6 = 197.630
D6 = 1.90
N4 = 1.772499
ν4 = 49.6


 R7 = 22.885
D7 = 6.75


 R8 = −142.776
D8 = 1.50
N5 = 1.834807
ν5 = 42.7


 R9 = 48.996
D9 = 0.15


 R10 = 36.010
D10 = 4.52
N6 = 1.698947
ν6 = 30.1


 R11 = −364.028
D11 = 2.34


 R12 = −38.722
D12 = 1.40
N7 = 1.834807
ν7 = 42.7


 R13 = 63.605
D13 = 3.40
N8 = 1.846660
ν8 = 23.9


 R14 = −115.913
D14 = Variable


 R15 = Stop
D15 = 1.40


 R16 = 151.712
D16 = 1.50
N9 = 1.805181
ν9 = 25.4


 R17 = 49.354
D17 = 4.73
N10 = 1.487490
ν10 = 79.2


 R18 = −58.993
D18 = 0.15


 R19 = 86.284
D19 = 2.99
N11 = 1.487490
ν11 = 79.2


 R20 = −132.595
D20 = 0.15


 R21 = 46.167
D21 = 3.35
N12 = 1.572501
ν12 = 57.7


 R22 = −923.062
D22 = Variable


 R23 = −145.199
D23 = 1.50
N13 = 1.651597
ν13 = 58.5


 R24 = 143.348
D24 = 1.71


 R25 = −68.339
D25 = 1.50
N14 = 1.622992
ν14 = 58.2


 R26 = 36.247
D26 = 3.50
N15 = 1.805181
ν15 = 25.4


 R27 = 147.323
D27 = Variable


 R28 = 381.611
D28 = 1.50
N16 = 1.846660
ν16 = 23.9


 R29 = 35.008
D29 = 6.33
N17 = 1.487490
ν17 = 79.2


 R30 = −42.191
D30 = 0.15


 R31 = 122.413
D31 = 3.25
N18 = 1.517417
ν18 = 52.4


 R32 = −104.441
D32 = 0.15


 R33 = 38.319
D33 = 6.60
N19 = 1.496999
ν19 = 81.5


 R34 = −45.455
D34 = 1.50
N20 = 1.806098
ν20 = 41.0


 R35 = −109.278
D35 = Variable


 R36 = 116.121
D36 = 1.50
N21 = 1.834807
ν21 = 42.7


 R37 = 20.308
D37 = 0.54


 R38 = 21.236
D38 = 9.37
N22 = 1.620041
ν22 = 36.3


 R39 = −29.161
D39 = 0.16


 R40 = −31.343
D40 = 1.80
N23 = 1.712995
ν23 = 53.9


 R41 = 31.521
D41 = Variable


‡ R42 = 201.994
D42 = 4.00
N24 = 1.487490
ν24 = 79.2


 R43 = −248.556













Variable
Focal length












spacing
28.80
100.00
339.99







D5 
1.80
38.63
78.19



D14
43.28
15.09
1.00



D22
1.90
11.43
15.13



D27
16.72
6.19
2.50



D35
1.10
3.99
2.00



D41
6.06
31.50
39.41











Aspheric coefficient










Surface 42:
A = 0.00000e+00 B = 2.66098e−06




C = 5.15592−09 D = −1.18901e−17




E = 0.00000+00 F = 0.00000e+00






















Numerical example 7


f = 28.80~291.99 Fno = 3.45~5.65 2ω = 73.8~8.5













R1 = 98.551
D1 = 3.00
N1 = 1.834000
ν1 = 37.2


R2 = 59.470
D2 = 8.70
N2 = 1.496999
ν2 = 81.6


R3 = 1004.462
D3 = 0.15


R4 = 68.082
D4 = 6.31
N3 = 1.496999
ν3 = 81.6


R5 = 830.984
D5 = Variable


R6 = 282.673
D6 = 1.90
N4 = 1.772499
ν4 = 49.6


R7 = 21.675
D7 = 6.52


R8 = −153.161
D8 = 1.60
N5 = 1.834807
ν5 = 42.7


R9 = 53.032
D9 = 0.15


R10 = 35.150
D10 = 3.49
N6 = 1.698947
ν6 = 30.1


R11 = 134.601
D11 = 3.08


R12 = −37.255
D12 = 1.40
N7 = 1.834807
ν7 = 42.7


R13 = 119.074
D13 = 3.40
N8 = 1.846660
ν8 = 23.9


R14 = −62.450
D14 = Variable


R15 = Stop
D15 = 1.40


R16 = 133.785
D16 = 1.50
N9 = 1.805181
ν9 = 25.4


R17 = 54.930
D17 = 4.41
N10 = 1.487490
ν10 = 79.2


R18 = −58.595
D18 = 0.15


R19 = 77.676
D19 = 2.84
N11 = 1.487490
ν11 = 79.2


R20 = −177.325
D20 = 0.15


R21 = 44.747
D21 = 2.94
N12 = 1.572501
ν12 = 57.7


R22 = 304.019
D22 = Variable


R23 = −123.489
D23 = 1.50
N13 = 1.651597
ν13 = 58.5


R24 = 183.723
D24 = 1.46


R25 = −78.748
D25 = 1.50
N14 = 1.622992
ν14 = 58.2


R26 = 30.113
D26 = 3.60
N15 = 1.805181
ν15 = 25.4


R27 = 113.618
D27 = Variable


R28 = 446.193
D28 = 1.50
N16 = 1.846660
ν16 = 23.9


R29 = 35.578
D29 = 6.64
N17 = 1.487490
ν17 = 79.2


R30 = −39.083
D30 = 0.15


R31 = 171.593
D31 = 3.26
N18 = 1.517417
ν18 = 52.4


R32 = −89.047
D32 = 0.15


R33 = 36.619
D33 = 6.41
N19 = 1.496999
ν19 = 81.5


R34 = −61.736
D34 = 1.50
N20 = 1.806098
ν20 = 41.0


R35 = −142.697
D35 = Variable


R36 = 234.444
D36 = 1.50
N21 = 1.834807
ν21 = 42.7


R37 = 23.318
D37 = 0.48


R38 = 24.136
D38 = 9.74
N22 = 1.620041
ν22 = 36.3


R39 = −29.954
D39 = 0.15


R40 = −31.189
D40 = 1.80
N23 = 1.712995
ν23 = 53.9


R41 = 42.831
D41 = Variable


R42 = −60.465
D42 = 4.00
N24 = 1.487490
ν24 = 79.2


R43 = −39.054













Variable
Focal length












spacing
28.80
100.00
291.99







D5 
1.80
28.59
62.92



D14
39.69
9.69
1.00



D22
2.34
13.21
16.29



D27
16.95
6.08
3.00



D35
1.99
7.40
2.03



D41
8.18
34.52
43.72






















Numerical example 8


f = 24.70~291.95 Fno = 3.21~5.66 2ω = 82.4~8.5













 R1 = 311.656
D1 = 8.00
N1 = 1.834009
ν1 = 37.2


 R2 = 92.339
D2 = 10.34
N2 = 1.496999
ν2 = 81.6


 R3 = −374.337
D3 = 0.15


 R4 = 89.364
D4 = 7.95
N3 = 1.651597
ν3 = 58.6


 R5 = 777.330
D5 = Variable


‡ R6 = 490.643
D6 = 1.90
N4 = 1.772499
ν4 = 49.6


 R7 = 20.909
D7 = 6.30


 R8 = −133.118
D8 = 1.60
N5 = 1.834807
ν5 = 42.7


 R9 = 73.437
D9 = 0.15


 R10 = 36.131
D10 = 3.69
N6 = 1.693947
ν6 = 30.1


 R11 = 246.684
D11 = 1.88


 R12 = −62.097
D12 = 1.40
N7 = 1.824807
ν7 = 42.7


 R13 = 50.441
D13 = 3.40
N8 = 1.844660
ν8 = 23.9


 R14 = −274.434
D14 = Variable


 R15 = stop
D15 = 1.40


 R16 = 31.940
D16 = 1.50
N9 = 1.805181
ν9 = 25.4


 R17 = 32.005
D17 = 4.52
N10 = 1.487490
ν10 = 79.2


 R18 = −67.414
D18 = 0.15


 R19 = 103.688
D19 = 2.70
N11 = 1.487490
ν11 = 79.2


 R20 = −106.172
D20 = 0.15


 R21 = 45.087
D21 = 2.96
N12 = 1.572601
ν12 = 57.7


 R22 = −242787.481
D22 = Variable


 R23 = −104.599
D23 = 1.50
N13 = 1.651597
ν13 = 58.5


 R24 = 127.364
D24 = 1.78


 R25 = −53.678
D25 = 1.60
N14 = 1.622992
ν14 = 58.2


 R26 = 26.147
D26 = 3.60
N15 = 1.805181
ν15 = 25.4


 R27 = 116.134
D27 = Variable


 R28 = 151.298
D28 = 1.50
N16 = 1.846660
ν16 = 23.9


 R29 = 32.559
D29 = 6.70
N17 = 1.487490
ν17 = 79.2


 R30 = −46.548
D30 = 8.15


 R31 = 205.161
D31 = 3.36
N18 = 1.517417
ν18 = 52.4


 R32 = −81.934
D32 = 0.15


 R33 = 41.236
D33 = 1.29
N19 = 1.496999
ν19 = 81.5


 R34 = −33.538
D34 = 1.50
N20 = 1.806098
ν19 = 81.5


 R35 = −62.853
D35 = Variable


 R36 = 656.920
D36 = 1.50
N21 = 1.824807
ν20 = 41.0


 R37 = 28.222
D37 = 0.60


 R38 = 29.549
D38 = 1.27
N22 = 1.620041
ν21 = 42.7


 R39 = −35.906
D39 = 0.16


 R40 = −51.361
D40 = 1.80
N23 = 1.712995
ν23 = 36.3


‡ R41 = 40.999
D41 = Variable


‡ R42 = 39.548
D42 = 4.00
N24 = 1.487490
ν24 = 79.2


 R43 = 44.826













Variable
Focal length












spacing
24.70
100.00
291.95







D5 
1.80
43.74
91.52



D14
35.54
6.13
0.99



D22
2.08
15.31
17.30



D27
17.72
4.49
2.50



D35
1.97
8.85
1.99



D41
1.39
27.19
39.14











Aspheric coeffient










Surface 6:
A = 0.00000e+00 B = 1.13766e−06




C = −6.21654e−10 D = −6.26234e−13




E = 0.00000e+00 F = 0.00000e+00



Surface 41:
A = 0.00000e+00 B = 4.50346e−06




C = 1.06751e−08 D = −1.81550e−12




E = 0.00000e+00 F 0.00000e+00



Surface 42:
A = 0.00000e+00 B = 6.40151e−07




C = 4.63968e−06 D = −1.888842e−12




E = 0.00000e+00 F = 0.00000e+00






















Numerical example 9


f = 24.70~232.95 Fno = 3.43~6.66 2ω = 82.4~10.6













 R1 = 274.104
D1 = 3.00
N1 = 1.834000
ν1 = 37.2


 R2 = 92.370
D2 = 10.15
N2 = 1.496999
ν2 = 31.6


 R3 = −1506.814
D3 = 0.15


 R4 = 91.730
D4 = 8.06
N3 = 1.696797
ν3 = 55.5


 R5 = 466.203
D5 = Variable


‡ R6 = 139.867
D6 = 1.90
N4 = 1.772499
ν4 = 49.6


 R7 = 18.885
D7 = 7.57


 R8 = −126.323
D8 = 1.60
N5 = 1.834807
ν5 = 42.7


 R9 = 82.344
D9 = 0.15


 R10 = 34.221
D10 = 3.47
N6 = 1.698947
ν6 = 30.1


 R11 = 116.347
D11 = 2.61


 R12 = −49.558
D12 = 1.40
N7 = 1.834807
ν7 = 42.7


 R13 = 92.243
D13 = 3.40
N8 = 1.848860
ν8 = 23.9


 R14 = −97.348
D14 = Variable


 R15 = Stop
D15 = 1.40


 R16 = 104.602
D16 = 1.50
N9 = 1.805131
ν9 = 25.4


 R17 = 40.960
D17 = 4.98
N10 = 1.487490
ν10 = 79.2


 R18 = −55.542
D18 = 0.16


 R19 = 92.515
D19 = 2.73
N11 = 1.487490
ν11 = 79.2


 R20 = −156.976
D20 = 0.15


 R21 = 47.122
D21 = 3.69
N12 = 1.572501
ν12 = 57.7


 R22 = −150.170
D22 = Variable


 R23 = −24.011
D23 = 1.50
N13 = 1.551597
ν13 = 58.5


 R24 = 94.241
D24 = 1.43


 R25 = −159.388
D25 = 1.50
N14 = 1.622992
ν14 = 58.2


 R26 = 25.292
D26 = 3.60
N15 = 1.805181
ν15 = 28.4


 R27 = 84.890
D27 = Variable


 R28 = 78.893
D28 = 1.50
N16 = 1.846660
ν16 = 23.9


 R29 = 29.483
D29 = 5.69
N17 = 1.487490
ν17 = 79.2


 R30 = −62.333
D30 = 0.15


 R31 = −693.362
D31 = 2.35
N18 = 1.517417
ν18 = 52.4


 R32 = −98.643
D32 = 0.15


 R33 = 43.894
D33 = 8.38
N19 = 1.496999
ν19 = 81.9


 R34 = −27.135
D34 = 1.60
N20 = 1.806098
ν20 = 41.0


 R35 = −52.462
D35 = Variable


 R36 = −373.303
D36 = 1.50
N21 = 1.834807
ν21 = 42.7


 R37 = 28.754
D37 = 1.29


 R38 = 41.301
D38 = 7.86
N22 = 1.620041
ν22 = 26.3


 R39 = −27.599
D39 = 0.15


 R40 = −37.547
D40 = 1.80
N23 = 1.712995
ν23 = 52.9


‡ R41 = 67.177
D41 = Variable


‡ R42 = −748.920
D42 = 4.00
N24 = 1.487499
ν24 = 79.2


 R43 = −93.833













Variable
Focal length












spacing
24.70
100.00
232.95







D5 
1.80
62.65
98.97



D14
40.15
11.63
1.30



D22
1.83
12.07
15.82



D27
16.48
6.24
2.49



D35
2.00
4.01
7.92



D41
3.59
31.71
34.99











Aspheric coefficient










Surface 6:
A = 0.00000e+00 B = 1.71252e+06




C = −7.05369e−10 D = −8.10676e−13




E = 0.00000e+00 F 32  0.00000e+00



Surface 41:
A = 0.00000e+00 B = 4.02700e−06




C = 1.76133e−08 D = −6.14451e−11




E = 0.00000e+00 F = 0.00000e+00



Surface 42:
A = 0.00000e+00 B = 1.66062e−06




C = 8.22956e−09 D = −7.23875e−12




E = 0.00000e+00 F = 0.00000e+00
























TABLE 1








Numerical
Numerical
Numerical
Numerical
Numerical



Conditional expression
example 1
example 2
example 3
example 4
example 5






















1a
1.1 < |(1 − β5t2) × βrt2|
2.66
2.89
2.97
1.53
1.78


2a
|f5/{square root over ((fw × ft))}|
0.91
0.90
1.00
2.12
1.90


3a
f6/{square root over ((fw × ft))}
1.65
1.64
1.84
3.01
2.96


4a
|f1/fw|
1.50
1.42
1.52
1.32
1.66


5a
f2/ft
0.48
0.57
0.69
0.86
1.00


6a
|f3/fw|
1.76
2.19
2.71
2.78
2.99


7a
f4/ft
0.57
0.63
0.79
1.05
1.15


8a
|f5/ft|
0.55
0.56
0.65
1.43
1.28


9a
f6/fw
2.73
2.63
2.83
4.47
4.38






















TABLE 2







Conditional
Numerical
Numerical
Numerical
Numerical



expression
example 6
example 7
example 8
example 9





















1b
|(1 − βBRat2) ×
8.37
7.60
6.15
6.02



βBRbt2|


2b
|fBRa/{square root over ((fw × ft))}|
0.35
0.42
0.54
0.62


3b
fBRb/{square root over ((fw × ft))}
2.32
2.32
6.50
2.90


4b
υp < 45
36.26
36.26
36.26
36.26


5b
f1/{square root over ((fw × ft))}
1.31
1.22
1.71
2.25


6b
|f2|/{square root over ((fw × ft))}
0.20
0.21
0.23
0.26


7b
fBR1/{square root over ((fw × ft))}
0.35
0.39
0.39
0.41


8b
|fBR2|/{square root over ((fw × ft))}
0.56
0.60
0.55
0.62


9b
fBR3/{square root over ((fw × ft))}
0.37
0.39
0.40
0.41

## Claims

1. A zoom lens system comprising, in order from an object
side to an image side:
a front lens group, which includes a plurality of lens units that move during zooming;
a lens unit with negative refractive power, which moves during zooming and moves towards the image side during focusing from an infinity object to a close-distance object; and
a lens unit with positive refractive power which does not move for zooming.

2. The zoom lens system according to claim 1, wherein
the zoom lens system forms an image on a photoelectric conversion element.

3. A camera comprising:
the zoom lens system according to claim 1; and
a photoelectric conversion element receiving an image formed by the zoom lens system.