Retrofocus type lens system having ultra-wide angle of view
AssigneeOlympus Optical Co., Ltd.
InventorJihei Nakagawa
Life of this patent
Estimating the term…
Abstract
A retrofocus type lens system having ultra-wide angle of view comprising a first positive meniscus lens component, a second negative meniscus lens component, a third negative meniscus lens component, a fourth positive lens component, a fifth negative meniscus lens component, a sixth lens component having positive refractive power, a seventh lens component having negative refractive power, an eighth positive meniscus lens component and a ninth positive lens component. Said lens system is so designed as to have a long back focal length and correct distortion, lateral chromatic aberration and so on.
Claims3
A retrofocus type lens system having ultra-wide angle of view comprising a first positive meniscus lens component, a second negative meniscus lens component, a third negative meniscus lens component, a fourth positive lens component, a fifth negative meniscus lens component, a sixth lens component having positive refractive power, a seventh lens component having negative refractive power, an eighth positive meniscus lens component and a ninth positive lens component, said lens system satisfying the following conditions:
- 1. 1.8f <
- f.sub.B <
- 2.3f
- 2. 4.5f <
- f.sub.1 <
- 6.5f
- 3. 4.5f <
- f.sub.4 <
- 6f
- 4. 0.05f <
- d.sub.10 <
- 0.1f
- 5. 0.6f <
- D.sub.6 <
- 0.75f
- wherein, the reference symbol f represents the total focal length of the entire lens system as a whole, f.sub.B is the back focal length of the entire lens system as a whole, the reference symbol f.sub.1 designates the focal length of the first lens component, the reference symbol f.sub.4 denotes the focal length of the fourth lens component, the reference symbol d.sub.10 represents the airspace between the fifth and sixth lens components, and the reference symbol D.sub.6 designates the thickness of the sixth lens component.
Dependencies are inferred from the claim text.