CAMERA HAVING AN AUTOFOCUS SYSTEM

• US 20070140676A1
• Filed: 12/12/2006
• Published: 06/21/2007
• Est. Priority Date: 12/16/2005
• Status: Active Grant

• Current Assignee: PENTAX RICOH IMAGING COMPANY, LTD.
• Original Assignee: Pentax Corporation (Hoya Corporation)
• Inventors: NAKAHARA, Naoto
• Granted Patent: US 7,620,310 B2
• Time in Patent Office: Days
• US Class Current: 396/103
• CPC Class Codes: G02B 7/38 measured at different points on the optical axis , e.g. focussing on two or more planes and comparing image data
• CPC Class Codes: G03B 13/36 Autofocus systems
• CPC Class Codes: H04N 23/673 based on contrast or high frequency components of image signals, e.g. hill climbing method
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements

Abstract

An AF camera includes a focusing lens group; an autofocus system which performs a searching process for detecting an in-focus position by moving the focusing lens group within a predetermined searching range to move the focusing lens group to the in-focus position; and a first switch and a second switch. After completion of the searching process, the autofocus system repeats the searching process over a first searching range closer to a far side than a near-side movable end upon the first switch being turned ON, with a current position of the focusing lens group serving as the near-side movable end; and the autofocus system repeats the searching process over a second searching range closer to a near side than a far-side movable end upon the second switch being turned ON, with a current position of the focusing lens group serving as the far-side movable end.

Claims

1. An AF camera comprising:

a focusing lens group;

an autofocus system which performs a searching process for detecting an in-focus position by moving said focusing lens group along an optical axis within a predetermined searching range to move said focusing lens group to said in-focus position; and

a first switch and a second switch,

wherein, after completion of said searching process, said autofocus system repeats said searching process over a first searching range closer to a far side than a near-side movable end upon said first switch being turned ON, with a current position of said focusing lens group serving as said near-side movable end; and

said autofocus system repeats said searching process over a second searching range closer to a near side than a far-side movable end upon said second switch being turned ON, with a current position of said focusing lens group serving as said far-side movable end.

2. The AF camera according to claim 1, wherein said AF camera includes a release button which activates said searching process upon being depressed by half a step, and

wherein, after completion of said searching process by said half-step depression of said release button, said autofocus system repeats said searching process over said first searching range upon said first switch being turned ON with said release button held depressed in said half-step;

and said autofocus system repeats said searching process over said second searching range upon said second switch being turned ON with said release button held depressed in said half-step.

3. The AF camera according to claim 1, wherein said AF camera comprises a macro mode,

wherein said autofocus system performs said searching process with a closest focus position in said macro mode serving as said near-side movable end, regardless of whether said macro mode is selected.

4. The AF camera according to claim 1, wherein said AF camera comprises a multi-way control button,

wherein said first switch and said second switch are turned ON/OFF in association with an operation of said multi-way control button, and

wherein said first switch and said second switch are turned ON upon said multi-way control button being depressed in a first direction and a second direction, respectively.

5. The AF camera according to claim 1, further comprising an imaging device which captures an object image via a photographing lens having said focusing lens group and converts said captured object image into an electrical image signal,

wherein, while moving said focusing lens group stepwise, said autofocus system captures an object image each time said focusing lens group is moved by one step, and detects a peak contrast among a plurality of contrasts of said electrical image signals of said captured object images to determine said in-focus position.

6. The AF camera according to claim 5, wherein said AF camera includes a release button which activates said searching process upon being depressed by half a step, and wherein stepwise movement of said focusing lens group in said searching process which is initially performed upon said release button being depressed by the half-step is smaller in step width than that in said searching process which is subsequently performed.

7. The AF camera according to claim 6, wherein said autofocus system moves said focusing lens group to said in-focus position which is obtained by said initially-performed searching process if said in-focus position is not obtained by said subsequently-performed searching process.

8. The AF camera according to claim 1, wherein said autofocus system comprises a stepping motor for moving said focusing lens group stepwise along said optical axis.

9. The AF camera according to claim 5, wherein said imaging device includes a light receiving surface on which a plurality of focus detection areas are arranged.

10. An autofocus system comprising:

a search function for detecting an in-focus position of a focusing lens group while said autofocus system moves said focusing lens group; and

a first switch and a second switch,

wherein said autofocus system performs said searching process with a current position of said focusing lens group serving as a near-side movable end thereof over a first searching range closer to a far side than said near-side movable end upon said first switch being turned ON, and said autofocus system performs said searching process with a current position of said focusing lens group serving as a far-side movable end thereof over a second searching range closer to a near side than said far side movable end upon said second switch being turned ON.

11. An autofocus system comprising:

a search function for detecting an in-focus position of a focusing lens group while said autofocus system moves said focusing lens group; and

an operational member for operating a first switch and a second switch,

wherein said autofocus system performs said searching process with a current position of said focusing lens group serving as a near-side movable end thereof over a first searching range closer to a far side than said near-side movable end upon said first switch being operated by said operational member, and said autofocus system performs said searching process with a current position of said focusing lens group serving as a far-side movable end thereof over a second searching range closer to a near side than said far side movable end upon said second switch being operated by said operational member.

12. An autofocus system comprising:

a search function for detecting an in-focus position of a focusing lens group while said autofocus system moves said focusing lens group; and

an operational member for operating a first switch and a second switch,

wherein said autofocus system performs said searching process with a current position of said focusing lens group serving as a near-side movable end thereof over a first searching range closer to a far side than said near-side movable end and moves said focusing lens group to an in-focus position within said first searching range upon said first switch being operated by said operational member, and said autofocus system performs said searching process with a current position of said focusing lens group serving as a far-side movable end thereof over a second searching range closer to a near side than said far side movable end and moves said focusing lens group to an in-focus position within said second searching range upon said second switch being operated by said operational member.