Compact zoom lens system
AssigneeSamsung Aerospace Industries, Ltd.
InventorYoung-Woo Park
Life of this patent
Estimating the term…
Abstract
Disclosed is a compact zoom lens system. The lens systems includes a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power. The first lens group and the third lens group are fixed against an image plane. The second lens group is linearly movable for variable magnification. The fourth lens group is able to compensate for moving of an image plane and is linearly movable toward an object for focusing. The lens system is governed by the following relationship: 0<.vertline.f.sub.II-2 /f.sub.II-3 .vertline.<1.2, where f.sub.II-2 is a focal length of a second lens of the second lens group, and f.sub.II-3 is a focal length of a third lens of the second lens group.
Claims11
A compact zoom lens system having an image plane side and an object side, comprising:
- a first lens group disposed at the object side of the system and having a positive refractive power;
- a second lens group disposed adjacent the first lens group and having a negative refractive power, the second lens group having first, second, and third lenses;
- a third lens group disposed adjacent the second lens group and having a positive refractive power;
- and
- a fourth lens group disposed at the image plane side of the system and adjacent the third lens group, the fourth lens group having a positive refractive power;
- wherein the first lens group and the third lens group are fixed with respect to an image plane, the second lens group is linearly movable for variable magnification, and the fourth lens group is linearly movable for focusing and compensating for movement of the image plane;
- and
- wherein the compact zoom lens system satisfies the following condition:
- 1.0<.vertline.f.sub.II-2 /f.sub.II-3 .vertline.<1.2
- where f.sub.II-2 is a focal length of the second lens of the second lens group, and f.sub.II-3 is a focal length of the third lens of the second lens group.
Dependencies are inferred from the claim text.