1. A zoom lens system for forming an optical image of an object on a light receiving surface with a diagonal length of 2Ymax of an image sensing device for converting the optical image into an electrical signal,
the zoom lens system being composed of, from an object side, a first group having a positive optical power, a second group having a negative optical power, a third group having a negative optical power, an aperture stop, and a plurality of groups having a positive optical power as a whole,
the zoom lens system achieving zooming by varying distances between the groups,
wherein the zoom lens system achieves focusing by moving the third group, and
wherein the zoom lens system fulfills conditional formulae (1) and (2) below:
1.5<frwYmax<2.1\u2003\u2003(1)
0.25<f2f3<0.6\u2003\u2003(2)
where, when the plurality of groups located to an image side of the aperture stop are referred to as rear groups,
frw represents a composite focal length of the rear groups at a wide-angle end;
Ymax represents a maximum image height;
f2 represents a focal length of the second group; and
f3 represents a focal length of the third group.
2. (canceled)
3. (canceled)
4. The zoom lens system according to claim 1,
wherein the rear groups are composed of, from the object side, a fourth group having a positive optical power and a fifth group having a positive optical power.
5. The zoom lens system according to claim 4,
wherein the zoom lens system fulfills conditional formula (3) below;
0.6<f4f5<0.8\u2003\u2003(3)
where
f4 represents a focal length of the fourth group; and
f5 represents a focal length of the fifth group.
6. The zoom lens system according to claim 4,
wherein the zoom lens system achieves camera shake correction by moving part of the fourth group perpendicularly to an optical axis.
7. The zoom lens system according to claim 1,
wherein the rear groups are composed of, from the object side, a fourth group having a positive optical power, a fifth group having a negative optical power, and a sixth group having a positive optical power.
8. The zoom lens system according to claim 7,
wherein the zoom lens system fulfills conditional formula (4) below:
0.2<f4f6<0.7\u2003\u2003(4)
where
f4 represents a focal length of the fourth group; and
f6 represents a focal length of the sixth group.
9. The zoom lens system according to claim 7,
wherein the fourth and sixth groups move as an integral unit during zooming.
10. The zoom lens system according to claim 7,
wherein the zoom lens system achieves camera shake correction by moving the fifth group perpendicularly to an optical axis.
11. The zoom lens system according to claim 1,
wherein the zoom lens system fulfills conditional formula (5) below:
6<f1fw<9\u2003\u2003(5)
where
f1 represents a focal length of the first group; and
fw represents a focal length of the entire system at a wide-angle end.
12. The zoom lens system according to claim 1,
wherein the zoom lens system fulfills conditional formulae (6) to (8) below:
1.1<\u03b223t\u03b223w<1.5\u2003\u2003(6)
1.9<\u03b2rt\u03b2rw<2.3\u2003\u2003(7)
1.3<(\u03b223t\u03b223w)(\u03b2rt\u03b2rw)<1.7\u2003\u2003(8)
where
\u03b223t represents a composite lateral magnification of the second and third groups at a telephoto end;
\u03b223w represents a composite lateral magnification of the second and third groups at a wide-angle end;
\u03b2rt represents a composite lateral magnification of the rear groups at the telephoto end; and
\u03b2rw represents a composite lateral magnification of the rear groups at the wide-angle end.
13. The zoom lens system according to claim 1,
wherein the zoom lens system has an f number of three or less.
14. The zoom lens system according to claim 1,
wherein the zoom lens system is an interchangeable lens for a digital camera.
15. An imaging optical device comprising the zoom lens system according to claim 1 and an image sensing device for converting an optical image formed on a light receiving surface into an electrical signal,
wherein the zoom lens system is arranged such that an optical image of a subject is formed on the light receiving surface of the image sensing device.
16. A digital device comprising the imaging optical device according to claim 15 so as to additionally have at least one of a function of taking a still picture of the subject or a function of taking a moving picture of the subject.
17. The zoom lens system according to claim 5,
wherein the zoom lens system achieves camera shake correction by moving part of the fourth group perpendicularly to an optical axis.
18. The zoom lens system according to claim 8,
wherein the fourth and sixth groups move as an integral unit during zooming.
19. The zoom lens system according to claim 8,
wherein the zoom lens system achieves camera shake correction by moving the fifth group perpendicularly to an optical axis.
20. The zoom lens system according to claim 4,
wherein the zoom lens system fulfills conditional formula (5) below:
6<f1fw<9\u2003\u2003(5)
where
f1 represents a focal length of the first group; and
fw represents a focal length of the entire system at a wide-angle end.
21. The zoom lens system according to claim 4,
wherein the zoom lens system fulfills conditional formulae (6) to (8) below:
1.1<\u03b223t\u03b223w<1.5\u2003\u2003(6)
1.9<\u03b2rt\u03b2rw<2.3\u2003\u2003(7)
1.3<(\u03b223t\u03b223w)(\u03b2rt\u03b2rw)<1.7\u2003\u2003(8)
where
\u03b223t represents a composite lateral magnification of the second and third groups at a telephoto end;
\u03b223w represents a composite lateral magnification of the second and third groups at a wide-angle end;
\u03b2rt represents a composite lateral magnification of the rear groups at the telephoto end; and
\u03b2rw represents a composite lateral magnification of the rear groups at the wide-angle end.
22. The zoom lens system according to claim 4,
wherein the zoom lens system has an f number of three or less.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A tire chain assembly, comprising:
a chain body including a plurality of net-shaped plates connected with each other;
the chain body having a first side having a first end provided with a first snapping member and a second end provided with a second snapping member detachably engaged with the first snapping member and a second side having a first end provided with a snapping hole and a second end provided with a rotation locking mechanism detachably locked on the snapping hole; wherein
the rotation locking mechanism includes:
a connecting plate pivotally mounted on the respective net-shaped plate;
a snapping member rotatably mounted on the connecting plate;
a locking hook pivotally mounted on the snapping member and detachably locked on the snapping hole.
2. The tire chain assembly in accordance with claim 1, wherein the connecting plate of the rotation locking mechanism has a mediate portion provided with a locking post, and the snapping member of the rotation locking mechanism has a mediate portion formed with a stepped locking groove that is movable to lock the locking post of the connecting plate.
3. The tire chain assembly in accordance with claim 1, wherein the connecting plate of the rotation locking mechanism has an edge provided with an elongated stop wall, and the snapping member of the rotation locking mechanism has an edge provided with a stop portion that is movable to rest on the stop wall of the connecting plate.
4. The tire chain assembly in accordance with claim 1, wherein the connecting plate of the rotation locking mechanism has a first end pivotally mounted on the respective net-shaped plate, and the snapping member of the rotation locking mechanism has a first end pivotally mounted on a second end of the connecting plate.
5. The tire chain assembly in accordance with claim 4, wherein the first end of the snapping member is formed with a through hole and a through bore spaced from the through hole and located adjacent to a mediate portion of the snapping member.
6. The tire chain assembly in accordance with claim 5, wherein the through hole of the snapping member is located at a center of rotation of the first end of the snapping member and the second end of the connecting plate.
7. The tire chain assembly in accordance with claim 5, wherein the rotation locking mechanism further includes a driving member mounted on the snapping member for driving the snapping member to rotate relative to the connecting plate to change a distance between the connecting plate and the snapping member and a distance between the connecting plate and the locking hook.
8. The tire chain assembly in accordance with claim 7, wherein the driving member of the rotation locking mechanism has two driving posts each respectively inserted into the through hole and the through bore of the snapping member for driving the snapping member to rotate relative to the connecting plate.
9. The tire chain assembly in accordance with claim 7, wherein the snapping member is driven by the driving member to rotate toward the connecting plate to drive the locking hook to move toward the connecting plate to reduce the distance between the connecting plate and the locking hook.
10. The tire chain assembly in accordance with claim 2, wherein when the snapping member is in line with and fully hidden in the connecting plate, the locking post of the connecting plate is inserted into and locked in the locking groove of the snapping member so as to lock the locking hook of the rotation locking mechanism on the snapping hole.
11. The tire chain assembly in accordance with claim 1, wherein the locking hook of the rotation locking mechanism has a first end pivotally mounted on a second end of the snapping member and a second end detachably locked in the snapping hole.
12. The tire chain assembly in accordance with claim 1, wherein the second side of the chain body has a separated mediate portion having a first section provided with the snapping hole and a second section provided with the rotation locking mechanism.
13. The tire chain assembly in accordance with claim 1, wherein the net-shaped plates are connected with each other by a plurality of connecting members.
14. The tire chain assembly in accordance with claim 13, wherein each of the net-shaped plates includes a net body having a plurality of extension arms, and a plurality of connecting arms each having a first end pivotally connected with a respective one of the extension arms of the net body and a second end pivotally connected with a respective one of the connecting members.
15. The tire chain assembly in accordance with claim 14, wherein the snapping hole is formed in the respective connecting arm.