Compact large-aperture photographic lens system with long back focal length

Claim 2

A compact large-aperture photographic lens system with long back focal length comprising a first, second, third, fourth fifth and sixth lens components, said first lens components being a positive meniscus lens, said second lens component being a positive meniscus lens, said third lens component being a negative meniscus lens, said fourth lens component being a cemented meniscus doublet, said fifth lens component being positive meniscus lens, said sixth lens component being a positive lens, said compact large-aperture photographic lens system with long back focal length satisfying the following conditions: (L/f) < 1 (L = Σd) (1) 0.6f < -r.sub.8 < 1.1.f (2) 0.1 < n.sub.4 - n.sub.5 < 0.2, 24 < ν.sub.5 - ν.sub.4 < 35 (3) ##EQU3## 1.5 < r5/r4 < 1.87, d.sub.4 < 0.05f (5)

Claim 3

16f < d 3 + d 4 + d 5 < 0.19f, 0.14f < d 7 + d 8 < 0.17f (6) 1.7 < n.sub.1, n.sub.2, n.sub.3, n.sub.4 < 1.86 (7) 1.6 < n.sub.5, n.sub.6, n.sub.7 < 1.82 (8) 40 < ν.sub.5, ν.sub.5, ν.sub.7 < 60 (9) Wherein reference symbol L represents the overall length of the lens system, reference symbol r 4 represents the radius of curvature of the surface on the image side of the second lens component, reference symbol r5 represents the radius of curvature of the surface on the object side of the third lens component, reference symbol r8 represents the radius of curvature of the cemented surface of the fourth lens component, reference symbols d3 and d5 respectively represent thicknesses of the second and third lens components, reference symbols d7 and d8 respectively represent thicknesses of respective lenses constituting the fourth lens component, reference symbol d4 represents the airspace between the second and third lens components, reference symbols n1 through n7 respectively represent refractive indices of respective lenses, reference symbols ν4 and ν5 respectively represent Abbe's numbers of respective lenses constituting the fourth lens component, reference symbols ν6 and ν7 respectively represent Abbe's numbers of the fifth and sixth lens components, reference symbol f represents the focal length of the lens system as a whose, reference symbol f23 represents the total focal length of the second and third lens components and reference symbol f45 represents the focal length of the fourth lens component.

Claim 4

16f < d 3 + d 4 + d 5 < 0.19f, 0.14f < d 7 + d 8 < 0.17f (6) 1.7 < n.sub.1, n.sub.2, n.sub.3, n.sub.4 < 1.86 (7) 1.6 < n.sub.5, n.sub.6, n.sub.7 < 1.82 (8) 40 < ν.sub.5, ν.sub.5, ν.sub.7 < 60 (9) Wherein reference symbol L represents the overall length of the lens system, reference symbol r 4 represents the radius of curvature of the surface on the image side of the second lens component, reference symbol r5 represents the radius of curvature of the surface on the object side of the third lens component, reference symbol r8 represents the radius of curvature of the cemented surface of the fourth lens component, reference symbols d3 and d5 respectively represent thicknesses of the second and third lens components, reference symbols d7 and d8 respectively represent thicknesses of respective lenses constituting the fourth lens component, reference symbol d4 represents the airspace between the second and third lens components, reference symbols n1 through n7 respectively represent refractive indices of respective lenses, reference symbols ν4 and ν5 respectively represent Abbe's numbers of respective lenses constituting the fourth lens component, reference symbols ν6 and ν7 respectively represent Abbe's numbers of the fifth and sixth lens components, reference symbol f represents the focal length of the lens system as a whose, reference symbol f23 represents the total focal length of the second and third lens components and reference symbol f45 represents the focal length of the fourth lens component.

Claim 5

A compact large-aperture photographic lens system with long back focal length according to claim 1, in which said compact large-aperture photographic lens system with long back focal length has the following numerical data: ______________________________________ f = 100, F 1.2, 2ω = 46° , f.sub.B = 75.2 r.sub.1 = 90.851 dl = 10.61 nl = 1.834 ν1 = 37.19 r2 = 546.619 d2 = 0.19 r3 = 55.369 d3 = 11.25 n2 = 1.8044 ν2 = 39.62 r4 = 95.056 d4 = 4 r5 = 158.146 d5 = 2.61 n3 = 1.7847 ν3 = 26.22 r6 = 36.590 d6 = 34.02 r7 = -33.822 d7 = 2.88 n4 = 1.84666 ν4 = 23.9 r8 = -82.077 d8 = 13.17 n5 = 1.734 ν5 = 51.52 r9 = -48.055 d9 = 0.19 r10 = -285.232 d10 = 11.72 n6 = 1.734 ν6 = 51.52 r11 = -64.922 d11 = 0.19 r12 = 157.079 d12 = 6.73 n7 = 1.734 ν7 =51.52 r13 = -910.494 L = Σd = 97.56, f23 = -126.919, f45 = -200.167 ##STR7## r5/r4 = 1.664 ______________________________________ Wherein, reference symbols r1 through r13 respectively represent radii of curvature of respective lens surfaces, reference symbols d1 through d12 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n1 through n7 respectively represent refractive indices of respective lenses and reference symbols ν1 through ν7 respectively represent Abbe's numbers of respective lenses.

Claim 6

A compact large-aperture photographic lens system with long back focal length according claim 1, in which said compact large-aperture photographic lens system with long back focal length has the following numerical data: ______________________________________ f = 100, F 1.2, 2ω = 46° , f.sub.B = 74.5 rl = 90.090 dl = 10.6 nl = 1.834 ν1 = 37.19 r2 = 586.320 d2 = 0.2 r3 = 54.675 d3 = 11.92 n2 = 1.8044 ν2 = 39.62 r4 = 91.779 d4 = 2.79 r5 = 156.838 d5 = 3.08 n3 = 1.7847 ν3 = 26.22 r6 = 35.379 d6 = 33.99 r7 = -33.908 d7 = 2.88 n4 = 1.84666 ν4 = 23.9 r8 = -72.065 d8 = 12.88 n5 = 1.734 ν5 = 51.52 r9 = -48.356 d9 = 0.2 r10 = -244.533 d10 = 11.69 n6 = 1.72916 ν6 = 54.7 r11 = -63.601 d11 = 0.2 r12 = 157.708 d12 = 6.73 n7 = 1.72916 ν7 = 54.7 r13 = 712.917 L = Σd = 97.14, f23 = -125.76, f45 = -202.40 ##STR8## r5/r4 = 1.709 ______________________________________ Wherein, reference symbols r1 through r13 respectively represent radii of curvature of respective lens surfaces, reference symbols d1 through d12 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n1 through n7 respectively represent refractive indices of respective lenses and reference symbols ν1 through ν7 respectively represent Abbe's numbers of respective lenses.

Claim 7

A compact large-aperture photographic lens system with long back focal length according to claim 1, in which said compact large-aperture photographic lens system with long back focal length has the following numerical data: ______________________________________ f = 100, F 1.2, 2ω = 46° , f.sub.B = 74.42 r1 = 92.507 dl = 10.6 nl = 1.834 ν1 = 37.19 r2 = 624.402 d2 = 0.2 r3 = 54.988 d3 = 11.92 n2 = 1.8044 ν2 = 39.62 r4 = 93.467 d4 = 2.79 r5 = 159.627 d5 = 3.54 n3 = 1.7847 ν3 = 26.22 r6 = 35.479 d6 = 34.00 r7 = -33.921 d7 = 2.88 n4 = 1.84666 ν4 = 23.9 r8 = -71.957 d8 = 12.88 n5 = 1.72916 ν5 = 54.7 r9 = -48.367 d9 = 0.2 r10 = -245.942 d10 = 11.69 n6 = 1.72916 ν6 = 54.7 r11 = -63.647 d11 = 0.2 r12 = 159.177 d12 = 6.73 n7 = 1.72916 ν7 = 54.7 r13 = -639.108 L = Σd = 97.6, f23 = -127.156, f45 = -200.50 ##STR9## r5/r4 = 1.708 ______________________________________ Wherein, reference symbols r1 through r13 respectively represent radii of curvature of respective lens surfaces, reference symbols d1 through d12 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n1 through n7 respectively represent refractive indices of respective lenses and reference symbols ν1 through ν7 respectively represent Abbe's numbers of respective lenses.

Claim 8

A compact large-aperture photographic lens system with long back focal length according to claim 1, in which said compact large-aperture photographic lens system with long back focal length has the following numerical data: ______________________________________ F = 100, F 1.2, 2ω = 46°, f.sub.B = 74.4 rl = 87.472 dl = 10.6 nl = 1.834 ν1 = 37.19 r2 = 480.599 d2 = 0.2 r3 = 55.420 d3 = 11.22 n2 = 1.8061 ν2 = 40.92 r4 = 94.348 d4 = 4.01 r5 = 152.809 d5 = 2.59 n3 = 1.7847 ν3 = 26.22 r6 = 35.214 d6 = 34.05 r7 = -33.757 d7 = 2.88 n4 = 1.84666 ν4 = 23.9 r8 = -88.400 d8 = 13.08 n5 = 1.734 ν5 = 51.52 r9 = -48.424 d9 = 0.2 r10 = -257.195 d10 = 11.70 n6 = 1.735 ν6 = 49.82 r11 = -63.662 d11 = 0.2 r12 = 153.235 d12 = 6.72 n7 = 1.735 ν7 = 49.82 r13 = -792.247 L = Σd = 97.42, f23 = -125.074, f45 = -189.085 ##STR10## r5/r4 = 1.62 ______________________________________ Wherein, reference symbols r1 through r 13 respectively represent radii of curvature of respective lens surfaces, reference symbols d1 through d12 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n1 through n7 respectively represent refractive indices of respective lenses and reference symbols ν1 through ν7 respectively represent Abbe's numbers of respective lenses.

Claim 9

A compact large-aperture photographic lens system with long back focal length according to claim 1, in which said compact large-aperture photographic lens system with long back focal length has the following numerical data: ______________________________________ f = 100, F 1.2 f.sub.B = 74.62 r1 = 82.84 dl = 10.19 nl = 1.83481 ν1 = 42.82 r2 = 375.812 d2 = 0.19 r3 = 54.248 d3 = 10.71 n2 = 1.834 ν2 = 37.19 r4 = 81.369 d4 = 2.88 r5 = 122.931 d5 = 3.25 n3 = 1.74 ν3 = 28.29 r6 = 34.208 d6 = 34.04 r7 = -32.638 d7 = 3.17 n4 = 1.84666 ν4 = 23.9 r8 = -101.792 d8 = 11.54 n5 = 1.6968 ν5 = 55.52 r9 = -46.762 d9 = 0.19 r10 = -183.948 d10 = 11.15 n6 = 1.7725 ν6 = 49.60 r11 = -58.952 d11 = 0.19 r12 = 169.800 d12 = 5.77 n7 = 1.79952 ν7 = 42.24 r13 = -699.104 L = Σd = 93.29 f23 = -134.5, f45 = -157.1 ##STR11## Petzval's sum = 0.158 ______________________________________ Wherein, reference symbols r1 through r13 respectively respresent radii of curvature of respective lens surfaces, reference symbols d1 through d12 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n1 through n7 respectively represent refractive indices of respective lenses and reference symbols ν1 through ν7 respectively represent Abbe's numbers of respective lenses.

Claim 10

A compact large-aperture photographic lens system with long back focal length according to claim 1, in which said compact large-aperture photographic lens system with long back focal length has the following numerical data: ______________________________________ f = 100, F 1.2, f.sub.B = 74.62 r1 = 82.171 dl = 10.22 nl = 1.83481 ν1 = 42.82 r2 = 379.002 d2 = 0.19 r3 = 54.883 d3 = 10.78 n2 = 1.834 ν2 = 37.19 r4 = 81.410 d4 = 2.88 r5 = 126.319 d5 = 3.29 n3 = 1.72825 ν3 = 28.46 r6 = 34.304 d6 = 33.95 r7 = -32.819 d7 = 3.11 n4 = 1.84666 ν4 = 23.9 r8 = -105.769 d8 = 11.49 n5 = 1.6779 ν5 = 55.33 r9 = -47.662 d9 = 0.19 r10 = -163.417 d10 = 10.95 n6 = 1.7725 ν6 = 49.6 r11 = -57.517 d11 = 0.19 r12 = 174.050 d12 = 5.82 n7 = 1.79952 ν7 = 42.24 r13 = - 435.498 Σd = 93.07 f23 = -133.2, f45 = -144.0 ______________________________________ Wherein, reference symbols r1 through r13 respectively represent radii of curvature of respective lens surfaces, reference symbols d1 through d12 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n1 through n7 respectively represent refractive indices of respective lenses and reference symbols ν1 through ν7 respectively represent Abbe's numbers of respective lenses.