Compact varifocal lens system capable of macrophotography
AssigneeMinolta Camera Kabushiki Kaisha
InventorMitsuo Yasukuni
Life of this patent
Estimating the term…
Abstract
A compact varifocal lens system, such as a zoom lens assembly, is provided having a front focusing lens component of negative refractive power, a variator lens component of positive refractive power, a compensator lens component of negative refractive power and a master lens component. The lens assembly has a compact configuration and further, provides a highly desirable macrophotography capability. The macrophotography mode of operation can be effected by fixing one of the variator and compensator lens components, or by separating one of the variator and compensator lens components into positive and negative subcomponents with a predetermined relative positioning of the subcomponents to provide a close-up focusing.
Claims19
A compact varifocal lens system capable of both a zooming and macrophotography mode of operation having a predetermined focal plane comprising:
- a first front lens component of overall negative refractive power;
- a second lens component of overall positive refractive power movable along an optical axis on the image side of said first front lens component;
- a third lens component of overall negative refractive power movable along the optical axis on the image side of said second lens component;
- and
- mounting means for said second and third lens components to provide a first mode of movement to vary the total focal length of the lens system without significant image-plane deviation and a second mode of movement to provide image-plane deviation for the purpose of focusing in the macrophotography range, one of said second and third lens components consists of positive and negative subcomponents, the negative subcomponent being located on the image side of the positive subcomponent, said subcomponents capable of being combined as a unit in said first mode and are separable from each other in said second mode.
A relatively compact varifocal lens system capable of macrophotography comprising:
- a first front lens component of overall negative refractive power;
- a second lens component of overall positive refractive power movable along an optical axis on the image side of said first front lens component;
- a third lens component of overall negative refractive power movable along the optical axis on the image side of said second lens component;
- first means for giving a first mode of movement to at least some of said second and third lens components to vary the total focal length of the lens system in a normal photography range;
- and
- second means for giving a second mode of movement to at least some of said second and third lens components to provide a macrophotography range of focusing including moving means for moving said third lens component toward the image side of the lens system and fixing said second lens component as said third lens component is moved for focusing in the macrophotography range.
A relatively compact varifocal lens system capable of macrophotography comprising:
- a first front lens component of overall negative refractive power;
- a second lens component of overall positive refractive power movable along an optical axis on the image side of said first front lens component;
- a third lens component of overall negative refractive power movable along the optical axis on the image side of said second lens component;
- first means for giving a first mode of movement to at least some of said second and third lens components to vary the total focal length of the lens system in a normal photography range;
- and
- second means for giving a second mode of movement to at least some of said second and third lens components to provide a macrophotography range of focusing including means for moving said second lens component toward the object side and fixing said third lens component as said second lens component is moved for focusing in the macrophotography range.
A compact varifocal lens system capable of macrophotography comprising the following design parameters:
- ______________________________________ f = 53.022 .about. 26.511 F/4.5 field angle 2.omega. = 22.8.degree. .about. 44.degree. Axial Refractive Index/ Radius of Curvature Distance Abbe's Number ______________________________________ ##STR41## 79.888 40.538 d.sub.1 1.0 N.sub.1 /V.sub.1 1.48749/70.1 d.sub.2 6.0 ##STR42## -33.408 -35.505 d.sub.3 1.0 N.sub.2 /V.sub.2 1.48749/70.1 d.sub.4 0.5 ##STR43## 44.434 183.286 d.sub.5 2.577 N.sub.3 /V.sub.3 1.58267/46.43 d.sub.6 0.493.about.20.493* ##STR44## 127.766 -27.179 -51.099 d.sub.7 d.sub.8 4.6 1.0 N.sub. 4 /V.sub.4 N.sub.5 /V.sub.5 1.62041/60.29 1.80518/25.41 d.sub.9 0.101 ##STR45## 49.983 -76.962 d.sub.10 2.859 N.sub.6 /V.sub.6 1.6779/55.38 d.sub.11 22.987.about.2.987*,** ##STR46## -39.175 46.117 d.sub.12 1.0 N.sub.7 /V.sub.7 1.48749/70.1 d.sub.13 3.834.about.3.834*,** ##STR47## .infin. .infin. d.sub.14 7.85 N.sub.p /V.sub.p 1.5168/64.04 d.sub.15 0.5 ##STR48## 27.203 -64.008 d.sub.16 1.7 N.sub.8 /V.sub.8 1.72124/38.04 d.sub.17 4.7 ##STR49## -17.657 32.968 d.sub.18 1.0 N.sub.9 /V.sub.9 1.74/28.28 d.sub.19 1.8 ##STR50## 445.167 -15.553 d.sub.20 2.342 N.sub.10 /V.sub.10 1.6935/53.39 ______________________________________
Dependencies are inferred from the claim text.