Downsize, high performance, and wide range magnification zoom lens and camera apparatus
AssigneeRicoh Company, Ltd.
InventorKazuyasu Ohashi
Life of this patent
Estimating the term…
Abstract
A zoom lens includes a first lens band having a positive focal length, a second lens band having a negative focal length, and at least third to fifth lens bands having positive focal lengths. An aperture diaphragm is located in the vicinity of the third lens band. When magnification i.e., zooming is performed from short to long focal point ends, the second lens band smoothly moves toward the third lens band and the fourth lens band simultaneously moves from the fifth lens band side toward a long focal point end so as to share a magnification function together with the second lens band.
Claims17
A camera apparatus comprising, a zoom lens, said zoom lens comprising in order from an object side:
- a first lens band having a positive focal length;
- a second lens band having a negative focal length;
- at least third to fourth lens bands having positive focal lengths;
- and
- a focus lens band arranged on the image side most and having a positive focal length;
- wherein, said second lens band smoothly moves toward the third lens band, and said fourth lens band moves toward a long focal point end in the vicinity of the third lens band when magnification is performed from short to long focal point ends;
- wherein, focusing is performed by only moving said focus lens band;
- wherein said first lens band is immobile when said magnification is performed;
- and
- wherein a distance (D1W) between the first and second lens bands in the short focal point end arrangement, a distance (D1T) between the first and second lens bands in the long focal point end arrangement, a distance (D3W) between the third and fourth lens bands in the short focal point end arrangement and a distance (D3T) between the third and fourth lens bands in the long focal point end arrangement substantially meet the following inequality:
- (D3W−D3T)/(D1T−D1W)>0.3.
A camera apparatus including a zoom lens groups in order from an object side, said camera apparatus comprising:
- a first lens band having a positive focal length;
- a second lens band having a negative focal length;
- at least third to fourth lens bands having positive focal lengths;
- and
- a focus lens band arranged on the image side of the fourth lens band,
- wherein said second lens band smoothly moves toward the third lens band, and said fourth lens band moves toward a long focal point end in the vicinity of the third lens band when magnification is performed from short to long focal point ends, and wherein focusing is performed by only moving said focus lens band;
- wherein said first lens band is immobile when said magnification is performed;
- and
- wherein a distance (D1W) between the first and second lens bands in the short focal point end arrangement, a distance (D1T) between the first and second lens bands in the long focal point end arrangement, a distance (D3W) between the third and fourth lens bands in the short focal point end arrangement and a distance (D3T) between the third and fourth lens bands in the long focal point end arrangement substantially meet the following inequality:
- (D3W−D3T)/(D1T−D1W)>0.3.
Dependencies are inferred from the claim text.