Patent ID: 11860345
Assignee: BAE SYSTEMS INFORMATION AND ELECTRONIC SYSTEMS INTEGRATION INC.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 5:
6. The discrete zoom lens according to claim 1, wherein the first configuration for the first changeable optical group comprises:

0.85<FL1/FCG1<1.15

0.90<FL1/FG2<1.20

3.55<OAL/FL1<3.95

0.90<FCG1/F11<1.10

−1.45<FCG1/F12<−1.20

1.20<FCG1/F13<1.45

0.65<FG2/F21<0.85

1.40<FG2/F22<1.70

−2.35<FG2/F23<−2.15

1.10<FG2/F24<1.30

−3.15<FG2/F25<−2.95

2.30<FG2/F26<2.55

0.10<FG2/F27<0.30

1.35<FG2/F28<1.70

1.35<FL1//CSD<1.55

2.50<V11/V12<2.70

0.90<V11/V13<1.20

0.90<V21/V22<1.20

2.50<V21/V23<2.70

2.50<V21/V24<2.70

2.50<V21/V25<2.70

0.90<V21/V26<1.20

0.90<V21/V27<1.20

0.90<V21/V28<1.20,, wherein:
FL1 is a focal length of a lens according to the first configuration,
FCG1 is a focal length of the first changeable optical group,
FCG2 is a focal length of the second group,
OAL is an overall length of a lens,
CSD is a cold shield distance from the aperture stop to the focal plane array,
F11, F12, F13 are focal length of first, second and third optical elements of the first changeable optical group,
F21, F22, F23, F24, F25, F26, F27, F28 are focal lengths of first, second, third, fourth, fifth, sixth, seventh and eighth optical elements of the second group,
V11, V12, V13 are the Abbe numbers of the first, second and third optical elements of the first changeable optical group, and
V21, V22, V23, V24, V25, V26, V27, V28 are the Abbe numbers of the first, second, third, fourth, fifth, sixth, seventh and eighth optical elements of the second group.