Compact zoom lens and a camera using the zoom lens
AssigneeRicoh Company, Ltd.
InventorKazuyasu Ohashi
Life of this patent
Estimating the term…
Abstract
A camera includes a zoom lens having a first lens group having a positive focal length, a second lens group having a negative focal length, an opening iris, a third lens group having a positive focal length, and a fourth lens group having a positive focal length. The first lens group, the second lens group, the opening iris, the third lens group and the fourth lens group are arranged in order from the object side, When zooming from a short focal point end toward a long focal point end, the second lens group moves from the object side toward the image side, and the third lens group first moves from the image side toward the object side, and then, after arriving at a position closest to the object side in an area at a long focal point side beyond an intermediate focal point, moves toward the image side.
Claims18
A zoom lens, comprising:
- a first lens group having a positive focal length;
- a second lens group having a negative focal length;
- an opening iris;
- a third lens group having a positive focal length;
- and
- a fourth lens group having a positive focal length,
- wherein the first lens group, the second lens group, the opening iris, the third lens group and the fourth lens group are arranged in order from an object side, and
- wherein the zoom lens is configured such that, when zooming from a short focal point end toward a long focal point end, the second lens group moves from an object side toward an image side, and the third lens group first moves from the image side toward the object side and then, after arriving at a position closest to the object side in an area at a long focal point side beyond an intermediate focal point, moves toward the image side so as to be disposed in a first positional relationship.
A camera, comprising a camera body and a zoom lens connected to the camera body, the zoom lens including:
- a first lens group having a positive focal length;
- a second lens group having a negative focal length;
- an opening iris;
- a third lens group having a positive focal length;
- and
- a fourth lens group having a positive focal length,
- wherein the first lens group, the second lens group, the opening iris, the third lens group and the fourth lens group are arranged in order from an object side, and
- wherein the zoom lens is configured such that, when zooming from a short focal point end toward a long focal point end, the second lens group moves from an object side toward an image side, and the third lens group first moves from the image side toward the object side and then, after arriving at a position closest to the object side in an area at a long focal point side beyond an intermediate focal point, moves toward the image side.
Dependencies are inferred from the claim text.