Lens system having large relative aperture and long focus
AssigneeNippon Kogaku K.K.
InventorSei Matui
Life of this patent
Estimating the term…
Abstract
A lens system comprising, as viewed from the object side, a first positive lens member having its convex surface facing the object side, a second positive lens member having its convex surface facing the object side, a third lens member, and a fourth positive lens member. The distance between the surface of the first lens member which faces the object side and the surface of the third lens member which faces the image side is from 0.4 times to 0.53 times the distance between the surface of the first lens member which faces the object side and the surface of the fourth lens member which faces the image side. The third lens member may comprise a positive lens and a negative lens which are joined together and which satisfy additional conditions.
Claims4
A lens system having a large relative aperture and long focus and having an object side and an image side, the system comprising, in series, as viewed from the object side, a positive first lens member having its convex surface facing the object side, a positive second lens member having its convex surface facing the object side, a negative third lens member, and a positive fourth lens member, the third lens member comprising a positive lens and a negative lens, the components of the lens system satisfying the following conditions:
- (I) 0.4 .SIGMA. d .ltoreq. [d1 + d2 + d3 + d4 + d5 + d6] .ltoreq. 0.53 .SIGMA. d, and
- (II) 0.4f .ltoreq. .vertline.r6.vertline. .ltoreq. 0.7f, n3 >
- n4, 32 >
- .lambda.4 >
- .lambda.3,
- where d ADSCRIPTS are the center thicknesses of the respective lenses and the air spaces between adjacent lenses, .SIGMA. d is the total optical length of the lens system, f is the composite focal length of the lens system, r ADSCRIPTS are the radii of curvature of the surfaces of respective lenses, n ADSCRIPTS are the indices of refraction for the glass used to make the respective lenses, and .nu. ADSCRIPTS are Abbe numbers for the respective lenses.
A lens system having a large relative aperture and long focus and having an object side and an image side, the system comprising, in series, as viewed from the object side, a positive first lens member having its convex surface facing the object side, a positive second lens member having its convex surface facing the object side, a negative third lens member, and a positive fourth lens member, the third lens member comprising a positive lens and a negative lens, the components of the lens system satisfying the following conditions:
- (I) 0.4 .SIGMA. d .ltoreq. [d1 + d2 + d3 + d4 + d5 + d6] .ltoreq. 0.53 .SIGMA. d, and
- (II) 0.4f .ltoreq. .vertline.r6.vertline. .ltoreq. 0.7f, n3 >
- n4, 32 >
- .nu.4 >
- .nu.3,
- where d ADSCRIPTS are the center thicknesses of the respective lenses and the air spaces between adjacent lenses, .SIGMA. d is the total optical length of the lens system, f is the composite focal length of the lens system, r ADSCRIPTS are the radii of curvature of the surfaces of respective lenses, n ADSCRIPTS are the indices of refraction from the glass used to make the respective lenses, and .nu. ADSCRIPTS are Abbe numbers for the respective lenses;
- the lens system having a total composite focal length of 100mm, a relative aperture of 1:2.8, and an angle of view of 18.1.degree. and the following specifications:
- ______________________________________ r1 = 40.444 d1 = 5.407 n1 = 1.6031 .nu.1 = 65.41 r2 = 289.580 d2 = 0.444 r3 = 30.222 d3 = 9.630 n2 = 1.6031 .nu.2 = 65.41 r4 = 67.912 d4 = 2.074 r5 = 173.333 d5 = 3.481 n3 = 1.69895 .nu.3 = 30.0 r6 = -40.741 d6 = 1.111 n4 = 1.68893 .nu.4 = 31.1 r7 = 19.884 d7 = 30.000 r8 = 62.222 d8 = 1.630 n5 = 1.7495 .nu.5 = 35.0 r9 = 195.494 ##STR4## ______________________________________
A lens system having a large relative aperture and long focus and having an object side and an image side, the system comprising, in series, as viewed from the object side, a positive first lens member having its convex surface facing the object side, a positive second lens member having its convex surface facing the object side, a negative third lens member, and a positive fourth lens member, the third lens member comprising a positive lens and a negative lens, the components of the lens system satisfying the following conditions:
- (I) 0.4 .SIGMA. d .ltoreq. [d1 + d2 + d3 + d4 + d5 + d6] .ltoreq. 0.53 .SIGMA. d, and
- (II) 0.4f .ltoreq. .vertline.r6.vertline. .ltoreq. 0.7f, n3 >
- n4, 32 >
- .nu.4 >
- .nu.3,
- where d ADSCRIPTS are the center thicknesses of the respective lenses and the air spaces between adjacent lenses, .SIGMA. d is the total optical length of the lens system, f is the composite focal length of the lens system, r ADSCRIPTS are the radii of curvature of the surfaces of respective lenses, n ADSCRIPTS are the indices of refraction for the glass used to make the respective lenses, and .nu. ADSCRIPTS are Abbe numbers for the respective lenses;
- the lens system having a total composite focal length of 100mm, a relative aperture of 1:2.8, and an angle of view of 18.1.degree. and the following specifications:
- ______________________________________ r1 = 41.630 d1 = 5.407 n1 = 1.62041 .nu.1 = 60.3 r2 = 300.296 d2 = 0.444 r3 = 28.778 d3 = 9.630 n2 = 1.62041 .nu.2 = 60.3 r4 = 61.593 d4 = 2.074 r5 = 157.876 d5 = 3.481 n3 = 1.78470 .nu.3 = 26.1 r6 = -58.637 d6 = 1.111 n4 = 1.74000 .nu.4 = 28.2 r7 = 19.616 d7 = 25.704 r8 = 62.222 d8 = 1.630 n5 = 1.72825 .nu.5 = 28.3 r9 = 186.713 ##STR5## ______________________________________
A lens system having a large relative aperature and long focus and having an object side and an image side, the system comprising, in series, as viewed from the object side, a positive first lens member having its convex surface facing the object side, a positive second lens member having its convex surface facing the object side, a negative third lens member, and a positive fourth lens member, the third lens member comprising a positive lens and a negative lens, the components of the lens system satisfying the following conditions:
- (I) 0.4 .SIGMA. d .ltoreq. [d1 + d2 + d3 + d4 + d5 + d6] .ltoreq. 0.53 .SIGMA. d, and
- (II) 0.4 f .ltoreq. .vertline.r6.vertline. .ltoreq. 0.7f, n3 >
- n4, 32 >
- .nu.4 >
- .nu.3,
- where d ADSCRIPTS are the center thicknesses of the respective lenses and the air spaces between adjacent lenses, .SIGMA. d is the total optical length of the lens system, f is the composite focal length of the lens system, r ADSCRIPTS are the radii of curvature of the surfaces of respective lenses, n ADSCRIPTS are the indices of refraction for the glass used to make the respective lenses, and .nu. ADSCRIPTS are Abbe numbers for the respective lenses;
- the lens system having a total composite focal length of 100mm, a relative aperture of 1:2.8, and an angle of view of 18.1.degree. and the following specifications:
- ______________________________________ r1 = 41.407 d1 = 5.407 n1 = 1.60881 .nu.1 = 58.9 r2 = 288.507 d2 = 0.444 r3 = 28.000 d3 = 9.630 n2 = 1.60881 .nu.2 = 58.9 r4 = 59.138 d4 = 2.074 r5 = 191.111 d5 = 3.481 n3 1.91761 .nu.3 = 21.4 r6 = -68.889 d6 = 1.111 n4 = 1.80518 .nu.4 = 25.5 r7 = 20.221 d7 = 18.000 r8 = 76.296 d8 = 1.630 n5 = 1.72825 .nu.5 = 28.3 r9 = 1750.370 ##STR6## ______________________________________
Dependencies are inferred from the claim text.