# US 4,396,255 A · Standard photographic lens system

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- Number: US 4,396,255 A
- Document ID: US4396255A
- Status: Granted
- Kind: A
- Application number: 06/197,278
- Filed: 1980-10-15
- Granted: 1983-08-02
- Earliest claimed: 1979-10-18
- Assignees: Olympus Optical Co., Ltd.
- Inventors: Toshihiro Imai
- Web page: https://patentgrep.com/patent/US4396255A

## CPC

- G02B 13/00: Optical objectives specially designed for the purposes specified below (with variable magnification {in general} G02B15/00)
- G02B 9/60: having five components only
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A standard photographic lens system comprising a first, second, third, fourth and fifth lens components in which the first lens component is a positive meniscus lens, the second lens component is a negative meniscus lens, the third lens component is a positive meniscus lens, the fourth lens component consists of a negative lens and positive lens which are cemented together or separated from each other, and the fifth lens components is a biconvex lens, the distance from the surface of the lens system to the film surface being short, the back focal length thereof being long and field angle thereof being 55.degree. or more.

## Claims

### Claim 1

A standard photographic lens system having wide field angle and comprising a first, second, third, fourth and fifth lens components, said first lens component being a positive meniscus lens arranged convex toward the object side, said second lens component being a negative meniscus lens arranged convex toward the object side, said third lens component being a positive meniscus lens arranged convex toward the object side, said fourth lens component consisting of a negative lens and positive lens, said fifth lens component being a biconvex lens, said standard photographic lens system satisfying the following conditions:
1.55f<L<1.7f (1)
0.88f<f.sub.B <0.93f (2)
-1.4f<f.sub.2 <-0.8f (3)
-3.2f<f.sub.23 <-0.8f (4)
0.45f<r.sub.3 <0.52f (5)
0.26f<r.sub.6 <0.37f (6)
-0.35f<r.sub.7 <-0.3f (7)
1.65<n.sub.6 <1.8 (8)
wherein reference symbol L represents the distance from the first surface of the lens system to the image surface, reference symbol f represents the focal length of the lens system as a whole, reference symbol f.sub.B represents the back focal length, reference symbol f.sub.2 represents the focal length of the second lens component, reference symbol f.sub.23 represents the total focal length of the second and third lens components, reference symbols r.sub.3, r.sub.6 and r.sub.7 respectively represent radii of curvature of the surface on the object side of the second lens component, surface on the image side of the third lens component and surface on the object side of the fourth lens component, and reference symbol n.sub.6 represents the refractive index of the fifth lens component.

### Claim 2 (depends on 1)

A standard photographic lens system having a wide field angle according to claim 1, in which said fourth lens component consists of a negative lens and positive lens separated from each other.

### Claim 3 (depends on 2)

A standard photographic lens system having a wide field angle according to claim 2 further satisfying the following conditions:
0.03<n.sub.4 -n.sub.5 ( 9)
0.03f<d.sub.4 ( 10)
-10f<f.sub.A ( 11)
-3f<f.sub.23 <-2.8f (4')
wherein reference symbols n.sub.4 and n.sub.5 respectively represent refractive indices of respective lenses constituting the fourth lens component, reference symbol d.sub.4 represents the airspace between the second and third lens components, and reference symbol f.sub.A represents the value expressed by the formula shown below wherein reference symbol r.sub.8 represents the surface on the image side of the negative lens constituting the fourth lens component, reference symbol r.sub.8 ' represents the surface on the object side of the positive lens constituting the fourth lens component, and reference symbol d.sub.7 ' represents the airspace between said negative lens and said positive lens: ##EQU2##

### Claim 4 (depends on 3)

A standard photographic lens system having a wide field angle according to claim 3, in which said standard photographic lens system has the following numerical data:
______________________________________ r.sub.1 = 1.072 d.sub.1 = 0.070 n.sub.1 = 1.72 .nu..sub.1 = 50.25 r.sub.2 = 5.078 d.sub.2 = 0.002 r.sub.3 = 0.464 d.sub.3 = 0.033 n.sub.2 = 1.60729 .nu..sub.2 = 49.29 r.sub.4 = 0.287 d.sub.4 = 0.043 r.sub.5 = 0.306 d.sub.5 = 0.089 n.sub.3 = 1.68250 .nu..sub.3 = 44.65 r.sub.6 = 0.344 d.sub.6 = 0.235 r.sub.7 = -0.327 d.sub.7 = 0.024 n.sub.4 = 1.76182 .nu..sub.4 = 26.55 r.sub.8 = -2.525 d'.sub.7 = 0.008 r'.sub.8 = -1.446 d.sub.8 = 0.116 n.sub.5 = 1.726 .nu..sub.5 = 53.56 r.sub.9 = - 0.387 d.sub.9 = 0.002 r.sub.10 = 4.976 d.sub.10 = 0.097 n.sub.6 = 1.757 .nu..sub.6 = 47.87 r.sub.11 = -0.826 f = 1, n.sub.4 - n.sub.5 = 0.036 f.sub.2 = -1.334, f.sub.A = -8.847 f.sub.23 = -2.869, L = 1.64 f.sub.B = 0.918 ______________________________________
wherein reference symbols r.sub.1 through r.sub.11 respectively represent radii of curvature of respective lens surfaces, reference symbols d.sub.1 through d.sub.10 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n.sub.1 through n.sub.6 respectively represent refractive indices of respective lenses, and reference symbols .nu..sub.1 through .nu..sub.6 respectively represent Abbe's numbers of respective lenses.

### Claim 5 (depends on 3)

A standard photographic lens system havin a wide field angle according to claim 3, in which said standard photographic lens system has the following numerical data:
______________________________________ r.sub.1 = 0.875 d.sub.1 = 0.070 n.sub.1 = 1.713 .nu..sub.1 = 53.89 r.sub.2 = 4.081 d.sub.2 = 0.002 r.sub.3 = 0.504 d.sub.3 = 0.040 n.sub.2 = 1.6172 .nu..sub.2 = 54.04 r.sub.4 = 0.286 d.sub.4 = 0.035 r.sub.5 = 0.294 d.sub.5 = 0.061 n.sub.3 = 1.6825 .nu..sub.3 = 44.65 r.sub.6 = 0.358 d.sub.6 = 0.234 r.sub.7 = -0.327 d.sub.7 = 0.023 n.sub.4 = 1.76182 .nu..sub.4 = 26.55 r.sub.8 = -4.290 d'.sub.7 = 0.013 r'.sub.8 = -1.299 d.sub.8 = 0.119 n.sub.5 = 1.713 .nu..sub.5 = 53.89 r.sub.9 = - 0.392 d.sub.9 = 0.002 r.sub.10 = 3.521 d.sub.10 = 0.097 n.sub.6 = 1.757 .nu..sub.6 = 47.87 r.sub.11 = -0.816 f = 1, n.sub.4 - n.sub.5 = 0.049 f.sub.2 = -1.154, f.sub.A = -4.761 f.sub.23 = -2.827 L = 1.61 f.sub.B = 0.918 ______________________________________
wherein reference symbols r.sub.1 through r.sub.11 respectively represent radii of curvature of respective lens surfaces, reference symbols d.sub.1 through d.sub.10 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n.sub.1 through n.sub.6 respectively represent refractive indices of respective lenses, and reference symbols .nu..sub.1 through .nu..sub.6 respectively represent Abbe's numbers of respective lenses.

### Claim 6 (depends on 1)

A standard photographic lens system having a wide field angle according to claim 1, in which said fourth lens component is arranged as a cemented doublet consisting of a negative lens and positive lens.

### Claim 7 (depends on 6)

A standard photographic lens system having a wide field angle according to claim 6 further satisfying the following conditions:
0.07<n.sub.4 -n.sub.5 ( 12)
0.07f<d.sub.4 ( 13)
-1.2f<f.sub.23 <-1.07f (4")
wherein reference symbols n.sub.4 and n.sub.5 respectively represent refractive indices of respective lenses constituting the fourth lens component, and reference symbol d.sub.4 represents the airspace between the second and third lens components.

### Claim 8 (depends on 6)

A standard photographic lens system having a wide field angle according to claim 6, in which said standard photographic lens system has the following numerical data:
______________________________________ r.sub.1 = 0.546 d.sub.1 = 0.090 n.sub.1 = 1.713 .nu..sub.1 = 53.89 r.sub.2 = 1.538 d.sub.2 = 0.002 r.sub.3 = 0.509 d.sub.3 = 0.028 n.sub.2 = 1.60342 .nu..sub.2 = 38.01 r.sub.4 = 0.262 d.sub.4 = 0.088 r.sub.5 = 0.289 d.sub.5 = 0.096 n.sub.3 = 1.6825 .nu..sub.3 = 44.65 r.sub.6 = 0.285 d.sub.6 = 0.203 r.sub.7 = -0.318 d.sub.7 = 0.024 n.sub.4 = 1.834 .nu..sub.4 = 37.19 r.sub.8 = 1.352 d.sub.8 = 0.107 n.sub.5 = 1.6968 .nu..sub.5 = 56.49 r.sub.9 = -0.377 d.sub.9 = 0.002 r.sub.10 = 5.257 d.sub.10 = 0.088 n.sub.6 = 1.6968 .nu..sub.6 = 56.49 r.sub.11 = -0.563 f = 1, f.sub.2 = -0.933 f.sub.23 = -1.104, f.sub.B = 0.902 n.sub.4 - n.sub.5 = 0.1372, L = 1.63 ______________________________________
wherein reference symbols r.sub.1 through r.sub.11 respectively represent radii of curvature of respective lens surfaces, reference symbols d.sub.1 through d.sub.10 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n.sub.1 through n.sub.6 respectively represent refractive indices of respective lenses, and reference symbols .nu..sub.1 through .nu..sub.6 respectively represent Abbe's numbers of respective lenses.

### Claim 9 (depends on 6)

A standard photographic lens system having a wide field angle according to claim 6, in which said standard photographic lens system has the following numerical data:
______________________________________ r.sub.1 = 0.560 d.sub.1 = 0.089 n.sub.1 = 1.72 .nu..sub.1 = 43.7 r.sub.2 = 1.462 d.sub.2 = 0.002 r.sub.3 = 0.495 d.sub.3 = 0.029 n.sub.2 = 1.62004 .nu..sub.2 = 36.25 r.sub.4 = 0.275 d.sub.4 = 0.106 r.sub.5 = 0.298 d.sub.5 = 0.093 n.sub.3 = 1.68250 .nu..sub.3 = 44.65 r.sub.6 = 0.285 d.sub.6 = 0.215 r.sub.7 = -0.309 d.sub.7 = 0.023 n.sub.4 = 1.78472 .nu..sub.4 = 25.71 r.sub.8 = 1.736 d.sub.8 = 0.106 n.sub.5 = 1.70154 .nu..sub.5 = 41.10 r.sub.9 = -0.370 d.sub.9 = 0.002 r.sub.10 = 6.881 d.sub.10 = 0.087 n.sub.6 = 1.73520 .nu..sub.6 = 41.08 r.sub.11 = -0.642 f = 1, f.sub.2 = -1.054 f.sub.23 = -1.169, f.sub.B = 0.89 n.sub.4 - n.sub.5 = 0.0832, L = 1.642 ______________________________________
wherein reference symbols r.sub.1 through r.sub.11 respectively represent radii of curvature of respective lens surfaces, reference symbols d.sub.1 through d.sub.10 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n.sub.1 through n.sub.6 respectively represent refractive indices of respective lenses, and reference symbols .nu..sub.1 through .nu..sub.6 respectively represent Abbe's numbers of respective lenses.