Macro lens system
AssigneeOlympus Optical Co., Ltd.
InventorYuko Kobayashi
Life of this patent
Estimating the term…
Abstract
A macro lens system assuring aberrations favorably corrected within a wide magnification range from 1.7.times. to 8.times. comprising a first positive meniscus lens component, a second negative cemented lens component, a third negative cemented meniscus lens component and a fourth positive meniscus lens component.
Claims5
A macro lens system comprising a first positive meniscus lens component having a convex surface on the object side, a second naegative cemented meniscus lens component consisting of a positive element and a negative element and having a convex surface on the object side, a third negative cemented meniscus lens component consisting of a positive element and a negative element and having a convex surface on the image side, and a fourth positive meniscus lens component having a convex surface on the image side, said macro lens system satisfying the following conditions:
- 1.7<n.sub.1, n.sub.6 ( 1)
- 50<.nu..sub.1, .nu..sub.6, 60<.nu..sub.2, .nu..sub.5 ( 2)
- 0.118f<d.sub.3 +d.sub.4 <0.128f (3)
- 0.184f<d.sub.5 <0.211f ( (4)
- 1.0<.vertline.r.sub.5 /r.sub.6 .vertline.<1.10 (5)
- 1.2<.vertline.r.sub.10 /r.sub.1 .vertline.<1.36 (6)
- 1.0<.vertline.r.sub.8 /r.sub.3 .vertline.<1.1 (7) 0.95<(d.sub.3 +d.sub.4)/(d.sub.6 +d.sub.7)<1.04 (8)
- wherein the reference symbol f represents focal length of said macro lens system as a whole, the reference symbols n.sub.1 and n.sub.6 designate refractive indices of said first lens component and said fourth lens component respectively, the reference symbols .nu..sub.1, .nu..sub.2, .nu..sub.5 and .nu..sub.6 denote Abbe's numbers of said first lens component, the object side element of said second lens component, the image side element of said third lens component and said fourth lens component respectively, the reference symbols d.sub.3, d.sub.4, d.sub.6 and d.sub.7 represent thicknesses of both the elements of said second lens component and both the elements of said third lens component respectively, the reference symbol d.sub.5 designates airspace reserved between said second and third lens components, and the reference symbols r.sub.1, r.sub.3, r.sub.5, r.sub.6, r.sub.8 and r.sub.10 denote radii of curvature on the object side surface of said first lens component, the object side surface and image side surface of said second lens component, the object side surface and image side surface of said third lens component and the image side surface of said fourth lens component respectively.
Dependencies are inferred from the claim text.