Photographic camera lens system having a short total length
AssigneeOlympus Optical Co., Ltd.
InventorKazushi Hyakumura
Life of this patent
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Abstract
A behind-stop type photographic camera lens system designed for an aperture ratio of F/2.8, a field angle of 60.degree., a short total length less than 0.37 f and favorably corrected aberrations, and comprising a first positive meniscus lens component, a second positive meniscus lens component, a third negative lens component, a fourth cemented lens component consisting of a biconvex lens element and a negative lens element.
Claims4
A photographic camera lens system having a short total length comprising a first positive meniscus lens component, a second positive meniscus lens component, a third negative lens component and a fourth cemented lens component consisting of a biconvex lens element and a negative lens element, and said lens system satisfying the following conditions:
- 1.86.ltoreq..phi..sub.1 +.phi..sub.2 .ltoreq.2.01 (1)
- 0.60.ltoreq..phi..sub.1 .ltoreq.0.86 (2)
- 1.77.ltoreq.n.sub.2 .ltoreq.1.81 (3)
- -0.40f.ltoreq.r.sub.8 23 -0.35f (4)
- 1.4.ltoreq..phi..sub.(67) /.phi..sub.(45) .ltoreq.1.9 (5)
- wherein the reference symbols r.sub.1 through r.sub.9 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d.sub.1 through d.sub.8 designate thicknesses of the respective lens elements and airspaces therebetween, the reference symbols n.sub.1 through n.sub.9 denote refractive indices of the lens elements and airspaces therebetween, the reference symbols .phi..sub.1 and .phi..sub.2 represent refractive powers of the first and second lens components, reference symbols .phi..sub.(45) and .phi..sub.(67) represent values which are defined by the following formulae:
- ##EQU3##
Dependencies are inferred from the claim text.