Super wide-angle lens systems

Claim 2

A super wide-angle lens system small in size and having a small F number, which is constructed with eight components and eight lenses, and comprises a first component of a positive meniscus lens that has at its object side a convex surface, second and third components of negative meniscus lenses that have at their object sides convex surfaces, a fourth component of a biconvex lens, a fifth component of a positive meniscus lens that has at its image side a convex surface, a sixth component of a biconcave lens, and seventh and eighth components of positive lenses, and which lens system is defined by the following five conditions: 1. 0.35f < f23 < 0.7f, and f23 < 0, 2. 0.2f < d4+d6 < 0.5f, 3. 0.5f < f45 < f, 4. 0.35f < d7+d9 < 0.7f, and 5. 0.1f < dVI < 0.4f where f is the composite focal length of the lens system, f23 is the composite focal length of said second and said third components, f45 is the composite focal length of said fourth and said fifth components, d4 is the air space between said second and said third components, d6 is the air space between said third and said fourth components, d7 is the axial thickness of said fourth component, d9 is the axial thickness of said fifth component, and dVI is the axial thickness of said sixth component, and wherein f is 1.0 mm, and the radii of curvatures r, the air spaces or axial thicknesses d, the refractive indexes n and the Abbe''s numbers Nu of the successive first through eighth components, designated L1 to L8, are defined by the following values:

Claim 3

A super wide-angle lens system small in size and having a small F number, which is constructed with eight components and eight lenses, and comprises a first component of a positive meniscus lens that has at its object side a convex surface, second and third components of negative meniscus lenses that have at their object sides convex surfaces, a fourth component of a biconvex lens, a fifth component of a positive meniscus lens that has at its image side a convex surface, a sixth component of a biconcave compound lens, and seventh and eighth components of positive lenses, and which lens system is defined by the following five conditions: 1. 0.35f < f23 < 0.7f, and f23 < 0, 2. 0.2f < d4+d6 < 0.5f, 3. 0.5f < f45 < f, 4. 0.35f < d7+d9 < 0.7f, and 5. 0.1f < dVI < 0.4f where f is the composite focal length of the lens system, f23 is the composite focal length of said second and said third components, f45 is the composite focal length of said fourth and said fifth components, d4 is the air space between said second and said third components, d6 is the air space between said third and said fourth components, d7 is the axial thickness of said fourth component, d9 is the axial thickness of said fifth component, and dVI is the axial thickness of said sixth component, and wherein f is 1.0 mm, and the radii of curvatures r, the air spaces or axial thicknesses d, the refractive indexes n and the Abbe''s numbers Nu of the successive first through eighth components, designated L1 to L8, are defined by the following values:

Claim 4

A super wide-angle lens system small in size and having a small F number, which is constructed with eight components and eight lenses, and comprises a first component of a positive meniscus lens that has at its object side a convex surface, second and third components of negative meniscus lenses that have at their object sides convex surfaces, a fourth component of a biconvex lens, a fifth component of a positive meniscus lens that has at its image side a convex surface, a sixth component of a biconcave compound lens, and seventh and eighth components of positive lenses, and which lens system is defined by the following five conditions: 1. 0.35f < f23 < 0.7f, and f23 < 0, 2. 0.2f < d4+d6 < 0.5f, 3. 0.5f < f45 < f, 4. 0.35f < d7+d9 < 0.7f, and 5. 0.1f < dVI < 0.4f where f is the composite focal length of the lens system, f23 is the composite focal length of said second and said third components, f45 is the composite focal length of said fourth and said fifth components, d4 is the air space between said second and said third components, d6 is the air space between said third and said fourth components, d7 is the axial thickness of said fourth component, d9 is the axial thickness of said fifth component, and dVI is the axial thickness of said sixth component, and wherein f is 1.0 mm, and the radii of curvatures r, the air spaces or axial thicknesses d, the refractive indexes n and the Abbe''s numbers Nu of the successive first through eighth components, designated L1 to L8, are defined by the following values: