Wide-angle zoom lens system
First Claim
Patent Images
1. A wide-angle zoom lens system, comprising from the object side to the image side:
- a first positive lens unit being stationary on an optical axis during a zooming operation;
a second negative lens unit shifting along the optical axis during the zooming operation;
a third positive lens unit being stationary on the optical axis during the zooming operation; and
a fourth positive lens unit shifting along the optical axis during the zooming operation;
wherein the zoom lens system fulfills the following conditions;
space="preserve" listing-type="equation">0.155<
Φ
1Z·
Y'"'"'.sup.3 /fs.sup.2 <
0.355
space="preserve" listing-type="equation">0.040<
(Φ
1/|Φ
2|)·
(Y'"'"'/fs).sup.3 <
0.065wherein;
Φ
1 represents a refractive power of the first lens unit;
Φ
2 represents a refractive power of the second lens unit;
Y'"'"' represents a maximum image height;
fs represents the shortest focal length of said zoom lens system; and
Z represents a zoom ratio.
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Abstract
A wide-angle zoom lens system comprises, from the object side to the image side, a first positive lens unit being stationary on an optical axis during a zooming operation, a second negative lens unit shifting along the optical axis during the zooming operation, a third positive lens unit being stationary on the optical axis during the zooming operation, and a fourth positive lens unit shifting along the optical axis during the zooming operation, wherein the refractive power of the first and second lens units fulfills the predetermined conditions.
17 Citations
12 Claims
-
1. A wide-angle zoom lens system, comprising from the object side to the image side:
-
a first positive lens unit being stationary on an optical axis during a zooming operation; a second negative lens unit shifting along the optical axis during the zooming operation; a third positive lens unit being stationary on the optical axis during the zooming operation; and a fourth positive lens unit shifting along the optical axis during the zooming operation; wherein the zoom lens system fulfills the following conditions;
space="preserve" listing-type="equation">0.155<
Φ
1Z·
Y'"'"'.sup.3 /fs.sup.2 <
0.355
space="preserve" listing-type="equation">0.040<
(Φ
1/|Φ
2|)·
(Y'"'"'/fs).sup.3 <
0.065wherein; Φ
1 represents a refractive power of the first lens unit;Φ
2 represents a refractive power of the second lens unit;Y'"'"' represents a maximum image height; fs represents the shortest focal length of said zoom lens system; and Z represents a zoom ratio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A wide-angle zoom lens system, comprising from the object side to the image side:
-
a first positive lens unit being stationary on an optical axis during a zooming operation; a second negative lens unit shifting along the optical axis during the zooming operation; a third positive lens being stationary on the optical axis during the zooming operation; and a fourth positive lens unit shifting along the optical axis during the zooming operation; wherein the zoom lens system fulfills the following conditions;
-
-
11. 155<
- Φ
1·
Z·
Y'"'"'3 /fs2 <
0.355
space="preserve" listing-type="equation">0.040<
(Φ
1/|Φ
2|)·
(Y'"'"'/fs).sup.3 <
0.065
space="preserve" listing-type="equation">-0.23<
R3F/R3R<
-0.45 (R3F>
0)wherein; Φ
1 represents a refractive power of the first lens unit;Φ
2 represents a refractive power of the second lens unit;Y'"'"' represents a maximum image height; fs represents the shortest focal length of said zoom lens system; Z represents a zoom ratio; R3F represents a radius of curvature of a surface located at the object side end of the third lens unit; and R3R represents a radius of curvature of a surface located at the image side end of the third lens unit.
- Φ
-
12. A wide-angle zoom lens system, comprising, from the object side to the image side:
-
a first positive lens unit being stationary on an optical axis during a zooming operation; a second negative lens unit shifting along the optical axis during the zooming operation; a third positive lens being stationary on the optical axis during the zooming operation; and a fourth positive lens unit shifting along the optical axis during the zooming operation, including a negative lens element and a positive lens element having at least one aspherical surface; wherein the zoom lens system fulfills the following conditions;
space="preserve" listing-type="equation">0.155<
Φ
1·
Z·
Y'"'"'.sup.3 /fs.sup.2 <
0.355
space="preserve" listing-type="equation">0.040<
(Φ
1/|Φ
2|)·
(Y'"'"'/fs).sup.3 <
0.065wherein; Φ
1 represents a refractive power of the first lens unit;Φ
2 represents a refractive power of the second lens unit;Y'"'"' represents a maximum image height; fs represents the shortest focal length of said zoom lens system; and Z represents a zoom ratio.
-
Specification