Standard photographic lens
AssigneeOlympus Optical Co., Ltd.
InventorToshihiro Imai
Life of this patent
Estimating the term…
Abstract
A standard photographic lens system comprising a first positive meniscus lens component, a second meniscus cemented doublet lens component, a third meniscus cemented doublet lens component and a fourth positive lens component. In said lens system, large radii of curvature are selected on the cemented surfaces of the second and third lens component respectively for facilitating to manufacture the respective elements of these two lens components, glass materials having low refractive indices are used for the respective lens elements for making it possible to manufacture said lens system at low cost, and various aberrations are favorably corrected.
Claims4
A standard photographic lens system comprising a first positive meniscus lens component, a second cemented doublet component consisting of a positive meniscus lens element and a negative meniscus lens element, a third cemented doublet component consisting of a negative lens element and a positive lens element and a forth positive lens component, and said lens system satisfying the conditions enumerated below:
- 0.41f<r.sub.3 <0.44f (1)
- 0.5f<r.sub.4 <1.2 (2)
- 0.25f<r.sub.5 <0.29f (3)
- 0.25f<-r.sub.6 <0.28f (4)
- f<-r.sub.7 <.sup..infin. ( 5)
- 0.33f<-r.sub.8 <0.4f (6)
- 0.22f<d.sub.5 <0.28f (7)
- 1.71<n.sub.1 <1.73
- 1.71<n.sub.2 <1.73
- 1.71<n.sub.5 <1.75
- 1.67<n.sub.6 <1.70 (8)
- 16<.nu..sub.2 -.nu..sub.3 <25 (9)
- 14<.nu..sub.5 -.nu..sub.4 <21 (10)
- 0.14f<d.sub.3 +d.sub.4 <0.19f (11)
- 0.10f<d.sub.6 +d.sub.7 <0.14f (12)
- wherein the reference symbols r.sub.3, r.sub.4 and r.sub.5 represent radii of curvature on the surfaces of the respective elements of the second lens component, the reference symbols r.sub.6, r.sub.7 and r.sub.8 designate radii of curvature on the surfaces of the respective elements of the third lens component, the reference symbol d.sub.5 denotes the airspace between the second and third lens components, the reference symbol n.sub.1 represents refractive index of the first lens component, the reference symbol n.sub.2 designates refractive index of the object side element of the second lens component, the reference symbol n.sub.5 denotes refractive index of the image side element of the third lens component, the reference symbol n.sub.6 represents refractive index of the fourth lens component, the reference symbols .nu..sub.2 and .nu..sub.3 designate Abbe's numbers of both the elements of the second lens component, the reference symbols .nu.4 and .nu.5 represent Abbe's numbers of both the elements of the third lens component, the reference symbols d.sub.3 and d.sub.4 represent thicknesses of both the elements of the second lens component, the reference symbols d.sub.6 and d.sub.7 designate thicknesses of both the elements of the third lens component and the reference symbol f designates focal length of the entire lens system as a whole.
Dependencies are inferred from the claim text.