Patent ID: 11934036
Assignee: RICOH COMPANY, LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 5:
6. The imaging lens system according to claim 1,
wherein the first sub-group includes a positive lens with a convex surface facing the object side and a negative lens, which are disposed in that order from the object side to the image side,
wherein conditional expressions (8) and (9) below are satisfied:

30<vd11<50(8);, and

θgF11>−0.002×vd11+0.656  (9), where
vd11 denotes Abbe number of material of the positive lens closest to the object side within the first sub-group, and
θgF11 denotes a partial dispersion ratio with respect to g line of the positive lens closest to the object side within the first sub-group.