Cata-dioptric type telephoto lens system

Claim 2

A cata-dioptric type telephoto lens system comprising a first, second, third, fourth and fifth lens system in the order according to the advancing direction of rays, said first lens being a positive meniscus lens arranged convex toward the object side, said second lens being a negative meniscus lens arranged convex toward the image side and having a reflecting surface formed on the convex surface thereof by leaving a transparent central portion, said third lens being a biconvex lens cemented to the surface on the image side of said first lens, said fourth lens being a biconcave lens cemented to the surface on the object side of said first lens and having a reflecting surface formed on the surface on the object side thereof, said fifth lens being a negative meniscus lens cemented to the surface on the object side of said second lens, said cata-dioptric type telephoto lens system satisfying the following conditions: 0.45f<r.sub.1 <0.75f (1) 0.29f<f.sub.12 <0.33f (2) 0.03f<d.sub.8 +d.sub.3 <0.05f (3) n.sub.3 >1.73 (4) n.sub.4 <1.58 (5) wherein reference symbol f represents the focal length of the lens system as a whole, reference symbol f 12 represents the total focal length of the first and second lenses, reference symbol r 1 represents the radius of curvature of the surface on the object side of the first lens, reference symbols d 3 and d 8 respectively represent thicknesses of the second and fifth lenses, and reference symbols n 3 and n 4 respectively represent refractive indices of the third and fourth lenses.

Claim 3

A cata-dioptric type telephoto lens system according to claim 1 further satisfying the following conditions: 0.13f<d.sub.2 <0.15f (6) n.sub.2 <1.6 (7) n.sub.5 <1.67 (8) ν.sub.5 <50 (9) 0.3f<f.sub.3 <0.4f (10) 0.18f<|f.sub.A |<0.25f (11) 0.18f<f.sub.25 <0.24f (12) wherein reference symbol d 2 represents the distance between the first and second lenses, reference symbols n 2 and n 5 respectively represent refractive indices of the second and fifth lenses, reference symbol ν 5 represents Abbe's number of the fifth lens, reference symbol f 3 represents the focal length of the third lens, reference symbol f A represents the total focal length of the system into which the rays enter through the surface on the image side of the third lens, pass through the third and first lenses, enter the fourth lens, are reflected by the surface on the object side of the fourth lens, pass through the fourth, first and third lenses again and go out of the system through the surface on the image side of the third lens, and reference symbol f 25 represents the total focal length of the fifth and second lenses.

Claim 4

A cata-dioptric type telephoto lens system according to claim 2, in which said cata-dioptric type telephoto lens system has the following numerical data: ______________________________________ ΣP = 0.360 r.sub.1 = 49.733 d.sub.1 = 2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.2 = 123.532 d.sub.2 = 13.694 r.sub.3 = -35.230 d.sub.3 = 1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.4 = -52.023 d.sub.3 = -1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.3 = -35.230 d.sub.4 = -12.658 r.sub.5 = -32.731 d.sub.5 = -1.036 n.sub.3 = 1.76200 ν.sub.3 = 40.20 r.sub.2 = 123.532 d.sub.1 = -2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.1 = 49.733 d.sub.6 = -0.622 n.sub.4 = 1.54771 ν.sub.4 = 62.83 r.sub.6 = -28.196 d.sub.6 = 0.622 n.sub.4 = 1.54771 ν.sub.4 = 62.83 r.sub.1 = 49.733 d.sub.1 = 2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.2 = 123.532 d.sub.5 = 1.036 n.sub.3 = 1.76200 ν.sub.3 = 40.20 r.sub.5 = -32.731 d.sub.7 = 9.964 r.sub.7 = -9.849 d.sub.8 = 2.694 n.sub.5 = 1.56444 ν.sub.5 = 43.78 r.sub.3 = -35.230 d.sub.3 = 1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.4 = -52.023 f = 100.0 2ω = 5.15° F.sub.NO = 7.0 T = 0.29 f.sub.1 = 139.9, f.sub.12 = 30.0, f.sub.3 = 34.1, f.sub.A = -20.1, f.sub.4 = -32.8 f.sub.25 = -22.4, S = 0.8715, f.sub.M = 70.05 ______________________________________ wherein reference symbols r 1 , r 2 , . . . respectively represent radii of curvature of respective lens surfaces given in the order according to the advancing direction of rays, reference symbols d 1 , d 2 , . . . respectively represent distances between respective lens surfaces given in the order according to the advancing direction of rays, reference symbols n 1 , n 2 , . . . respectively represent refractive indices of respective lenses, reference symbols ν 1 , ν 2 , . . . respectively represent Abbe's numbers of respective lenses, reference symbol ΣP represents Petzval's sum, reference symbol T represents the telephoto ratio, reference symbol S represents the maximum advancing stroke of the front lens, and reference symbol f M represents the focal length of the lens system as a whole when the front lens is fully advanced.

Claim 5

A cata-dioptric type telephoto lens system according to claim 2, in which said cata-dioptric type telephoto lens system has the following numerical data: ______________________________________ ΣP = 0.400 r.sub.1 = 68.382 d.sub.1 = 2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.2 = 292.413 d.sub.2 = 14.165 r.sub.3 = -33.647 d.sub.3 = 1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.4 = -52.051 d.sub.3 = -1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.3 = -33.647 d.sub.4 = -13.128 r.sub.5 = -33.372 d.sub.5 = -1.036 n.sub.3 = 1.83400 ν.sub.3 = 37.19 r.sub.2 = 292.413 d.sub.1 = -2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.1 = 68.382 d.sub.6 = -0.622 n.sub.4 = 1.46450 ν.sub.4 = 65.94 r.sub.6 = -28.161 d.sub.6 = 0.622 n.sub.4 = 1.46450 ν.sub.4 = 65.94 r.sub.1 = 68.382 d.sub.1 = 2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.2 = 292.413 d.sub.5 = 1.036 n.sub.3 = 1.83400 ν.sub.3 = 37.19 r.sub.5 = -33.372 d.sub.7 = 10.434 r.sub.7 = -9.854 d.sub.8 = 2.694 n.sub.5 = 1.64769 ν.sub.5 = 33.80 r.sub.3 = -33.647 d.sub.3 = 1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.4 = -52.051 f = 100.0, 2ω = 5.15°, F.sub.NO = 7.0, T = 0.297 f.sub.1 = 151.0, f.sub.12 = 31.5, f.sub.3 = 36.0, f.sub.A = -24.9, f.sub.4 = -42.9 f.sub.25 = -19.9, S = 0.9258, f.sub.M = 69.90 ______________________________________ wherein reference symbols r 1 , r 2 , . . . respectively represent radii of curvature of respective lens surfaces given in the order according to the advancing direction of rays, reference symbols d 1 , d 2 , . . . respectively represent distances between respective lens surfaces given in the order according to the advancing direction of rays, reference symbols n 1 , n 2 , . . . respectively represent refractive indices of respective lenses, reference symbols ν 1 , ν 2 , . . . respectively represent Abbe's numbers of respective lenses, reference symbol ΣP represents Petzval's sum, reference symbol T represents the telephoto ratio, reference symbol S represents the maximum advancing stroke of the front lens, and reference symbol f M represents the focal length of the lens system as a whole when the front lens is fully advanced.

Claim 6

A cata-dioptric type telephoto lens system according to claim 2, in which said cata-dioptric type telephoto lens system has the following numerical data: ______________________________________ ΣP = 0.190 r.sub.1 = 49.830 d.sub.1 = 2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.2 = 135.120 d.sub.2 = 13.555 r.sub.3 = -35.495 d.sub.3 = 1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.4 = -52.286 d.sub.3 = -1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.3 = -35.495 d.sub.4 = -12.520 r.sub.5 = -39.896 d.sub.5 = -1.036 n.sub.3 = 1.80610 ν.sub.3 = 40.95 r.sub.2 = 135.120 d.sub.1 = -2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.1 = 49.830 d.sub.6 = -0.622 n.sub.4 = 1.49831 ν.sub.4 = 65.03 r.sub.6 = -28.370 d.sub.6 = -0.622 n.sub.4 = 1.49831 ν.sub.4 = 65.03 r.sub.1 = 49.830 d.sub.1 = 2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.2 = 135.120 d.sub.5 = 1.036 n.sub.3 = 1.80610 ν.sub.3 = 40.95 r.sub.5 = -39.896 d.sub.7 = 9.825 r.sub.7 = -9.490 d.sub.8 = 2.694 n.sub.5 = 1.53172 ν.sub.5 = 48.90 r.sub.3 = -35.495 d.sub.3 = 1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.4 = -52.286 f = 100.0, 2ω = 5.15°, F.sub.NO = 7.0, T = 0.289 f.sub.1 = 132.8, f.sub.12 = 29.9, f.sub.3 = 38.3, f.sub.A = -19.7, f.sub.4 = - 36.2 f.sub.25 = -22.5, S = 0.8539, f.sub.M = 70.24 ______________________________________ wherein reference symbols r 1 , r 2 , . . . respectively represent radii of curvature of respective lens surfaces given in the order according to the advancing direction of rays, reference symbols d 1 , d 2 , . . . respectively represent distances between respective lens surfaces given in the order according to the advancing direction of rays, reference symbols n 1 , n 2 , . . . respectively represent refractive indices of respective lenses, reference symbols ν 1 , ν 2 , . . . respectively represent Abbe's numbers of respective lenses, reference symbol ΣP represents Petzval's sum, reference symbol T represents the telephoto ratio, reference symbol S represents the maximum advancing stroke of the front lens, and reference symbol f M represents the focal length of the lens system as a whole when the front lens is fully advanced.

Claim 7

A cata-dioptric type telephoto lens system according to claim 2, in which said cata-dioptric type telephoto lens system has the following numerical data: ______________________________________ ΣP = 0.400 r.sub.1 = 60.090 d.sub.1 = 2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.2 = 221.654 d.sub.2 = 13.816 r.sub.3 = -34.214 d.sub.3 = 1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.4 = -52.256 d.sub.3 = -1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.3 = -34.214 d.sub.4 = -12.780 r.sub.5 = -33.981 d.sub.5 = -1.036 n.sub.3 = 1.80440 ν.sub.3 = 39.62 r.sub.2 = 221.654 d.sub.1 = -2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.1 = 60.090 d.sub.6 = -0.622 n.sub.4 = 1.46450 ν.sub.4 = 65.94 r.sub.6 = -27.957 d.sub.6 = 0.622 n.sub.4 = 1.46450 ν.sub.4 = 65.94 r.sub.1 = 60.090 d.sub.1 = 2.062 n.sub.1 = 1.58913 ν.sub.1 = 61.11 r.sub.2 = 221.654 d.sub.5 = 1.036 n.sub.3 = 1.80440 ν.sub.3 = 39.62 r.sub.5 = -33.981 d.sub.7 = 10.086 r.sub.7 = -9.294 d.sub.8 = 2.694 n.sub.5 = 1.58144 ν.sub.5 = 40.75 r.sub.3 = -34.214 d.sub.3 = 1.861 n.sub.2 = 1.56732 ν.sub.2 = 42.83 r.sub.4 = -52.256 f = 100.0, 2ω = 5.15°, F.sub.NO = 7.0, T = 0.293 f.sub.1 = 139.3, f.sub.12 = 31.0, f.sub.3 = 36.7, f.sub.A = -23.3, f.sub.4 = -41.0 f.sub.25 = -20.3, S = 0.8978, f.sub.M = 69.87 ______________________________________ wherein reference symbols r 1 , r 2 , . . . respectively represent radii of curvature of respective lens surfaces given in the order according to the advancing direction of rays, reference symbols d 1 , d 2 , . . . respectively represent distances between respective lens surfaces given in the order according to the advancing direction of rays, reference symbols n 1 , n 2 , . . . respectively represent refractive indices of respective lenses, reference symbols ν 1 , ν 2 , . . . respectively represent Abbe's numbers of respective lenses, reference symbol ΣP represents Petzval's sum, reference symbol T represents the telephoto ratio, reference symbol S represents the maximum advancing stroke of the front lens, and reference symbol f M represents the focal length of the lens system as a whole when the front lens is fully advanced.