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

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

0.90<FL2/FCG2<1.10

1.45<FL2/FG2<1.65

2.50<OAL/FL1<2.70

1.55<FCG2/F201<1.65

−1.15<FCG2/F202<−0.85

1.40<FCG2/F203<1.65

1.90<FL1//CSD<2.15

2.50<V201/V202<2.70

0.90<V21/V203<1.20, −wherein

FL1 is a focal length of a lens according to the first configuration,
FL2 is a focal length of a lens according to the second configuration,
FCG2 is a focal length of the second changeable optical group according to the second configuration,
FG2 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,
F201, F201, F203 are focal lengths of first, second and third optical elements of the second 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,
V201, V202, V203 are the Abbe numbers of the first, second and third optical elements of the second 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.