Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
252 words
A compact zoom lens comprising first to fourth lens groups sequentially arranged from an object side, the first, second and fourth lens groups respectively having negative, positive and negative focal lengths; the zoom lens being constructed such that a distance between the first and second lens groups is decreased, a distance between the second and third lens groups is increased, and a distance between the third and fourth lens groups is decreased when a zooming operation is performed from a wide angle end to a telescopic end; and a focal length f 1 of the first lens group, a focal length f 2 of the second lens group, a focal length f 2 ,3,4W of a combined lens system of the second, third and fourth lens groups at the wide angle end, a focal length f 2 ,3,4T of the combined lens system of the second, third and fourth lens groups at the telescopic end, a focal length f 3 ,4T of a combined lens system of the third and fourth lens groups at the telescopic end, a focal length f W of an entire lens system at the wide angle end, and a focal length f T of the entire lens system at the telescopic end satisfying the following conditions, [f.sub.1 +f.sub.2,3,4W {2-(f.sub.1 /f.sub.W)-(f.sub.W /f.sub.1)}]/f.sub.T <0.6 (1) [f.sub.1 +f.sub.2,3,4T {2-(f.sub.1 /f.sub.T)-(f.sub.T /f.sub.1)}]/f.sub.T <0.6 (2) 0.6<|f.sub.3,4T |/f.sub.2 <6.0 (3) 0.8<f.sub.2 /f.sub.2,3,4T <1.4 (4) 0.5<|f.sub.1 |/√[f.sub.W ·f.sub.T ]<1.3(5) where symbol √[ ] means a square root of a value within bracket [ ].
Claim 2
Dependent Claim
252 words
A compact zoom lens comprising first to fourth lens groups sequentially arranged from an object side, the first, second and fourth lens groups respectively having negative, positive and negative focal lengths; the zoom lens being constructed such that a distance between the first and second lens groups is decreased, a distance between the second and third lens groups is increased, and a distance between the third and fourth lens groups is decreased when a zooming operation is performed from a wide angle end to a telescopic end; and a focal length f 1 of the first lens group, a focal length f 2 of the second lens group, a focal length f 2 ,3,4W of a combined lens system of the second, third and fourth lens groups at the wide angle end, a focal length f 2 ,3,4T of the combined lens system of the second, third and fourth lens groups at the telescopic end, a focal length f 3 ,4T of a combined lens system of the third and fourth lens groups at the telescopic end, a focal length f W of an entire lens system at the wide angle end, and a focal length f T of the entire lens system at the telescopic end satisfying the following conditions, [f.sub.1 +f.sub.2,3,4W {2-(f.sub.1 /f.sub.W)-(f.sub.W /f.sub.1)}]/f.sub.T <0.6 (1) [f.sub.1 +f.sub.2,3,4T {2-(f.sub.1 /f.sub.T)-(f.sub.T /f.sub.1)}]/f.sub.T <0.6 (2) 0.6<|f.sub.3,4T |/f.sub.2 <6.0 (3) 0.8<f.sub.2 /f.sub.2,3,4T <1.4 (4) 0.5<|f.sub.1 |/√[f.sub.W ·f.sub.T ]<1.3(5) where symbol √[ ] means a square root of a value within bracket [ ].
Claim 3
Dependent Claim
19 words
A compact zoom lens as claimed in claim 1, wherein a diaphragm is disposed in the third lens group.
Claim 4
Dependent Claim
89 words
A compact zoom lens as claimed in claim 2, wherein a diaphragm is arranged on the object side of the third lens group and the zoom lens has a super wide angle end for providing a focal length shorter than that at the wide angle end, and at least the distance between the first and second lens groups, and a distance between the above diaphragm and the third lens group are increased when the zooming operation is performed from the wide angle end to the super wide angle end.
Claim 5
Dependent Claim
35 words
A compact zoom lens as claimed in claim 1 or 2, wherein a focusing operation toward a short distance is performed by integrally moving the third and fourth lens groups on an image face side.