Autofocus camera

• US 5,499,074 A
• Filed: 05/30/1995
• Issued: 03/12/1996
• Est. Priority Date: 11/09/1990
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Nakano, Yoshiyuki, Mori, Ryuichi, Matsukawa, Nobuo, Ohsawa, Keiji, Nishioka, Sunao
• Primary Examiner(s): ADAMS JR, RUSSELL E
• Application Number:
  US08/453,462
• Time in Patent Office: 287 Days
• Field of Search: 354/402-409
• US Class Current: 396/121
• CPC Class Codes: G02B 7/346 using horizontal and vertical areas in the pupil plane, i.e. wide area autofocusing

Abstract

An autofocus camera conducts a focus detection operation with one of differently directed sets of photoelectric conversion elements which is given priority according to the detected attitude of the camera. If focusing cannot be effected using the elements given priority, a focus detection operation is automatically conducted with the other elements. Also provided is a camera having a first mode of operation in which focusing detecting operations are conducted which collectively utilize outputs of all of the elements of differently directed sets of photoelectric conversion elements when a first camera attitude is detected, and a second mode of operation in which focusing detecting operations are conducted which collectively disregard the output of at least one conversion element when a second camera attitude is detected.

Claims

1. An autofocus camera comprising:

a first photoelectric conversion unit to receive subject light from a detecting region extended in one direction of a photographic image plane and to perform photoelectric conversion;

a second photoelectric conversion unit to receive subject light from a detecting region extended in a direction different from said one direction of said photographic image plane and to perform photoelectric conversion;

an attitude detector to detect attitude of the camera;

a focus detector which selects one of said first and second photoelectric conversion units corresponding to a predetermined priority direction in the detected attitude of the camera and which conducts a focus detection operation using the selected photoelectric conversion unit, said focus detector discriminating based on a result of said focus detection operation whether focus can be detected using the selected photoelectric conversion unit, and, if it is discriminated that focus cannot be detected using the selected photoelectric conversion unit, conducting a focus detection operation using the other of said first and second photoelectric conversion units, said focus detector further providing a focus detection result to be used for focus control; and

a lens driving unit to drive and focus a photographic lens in accordance with the focus detection result from said focus detector.

2. An autofocus camera according to claim 1, wherein said first photoelectric conversion unit is horizontally oriented and said second photoelectric conversion unit is vertically oriented when the camera is in a horizontal attitude.

3. An autofocus camera according to claim 2, wherein said first photoelectric conversion unit is divided into a plurality of detection regions, said predetermined priority direction is horizontal, and said focus detector has an operating mode in which, when the camera attitude is such that said first photoelectric conversion unit is vertically oriented, said focus detector conducts a focus detection operation with the uppermost of said plurality of detection regions and controls said lens driving unit giving priority to said uppermost region over said second photoelectric conversion unit.

4. An autofocus camera according to claim 3, wherein, in said operating mode, said focus detector calculates a difference between a focus detection output obtained using said second photoelectric conversion unit and a focus detection output obtained using said uppermost detection region, and controls said lens driving unit in accordance with the focus detection output corresponding to said uppermost detection region when said difference is less than a predetermined value and in accordance with the focus detection output of said second photoelectric conversion unit when said difference is greater than said predetermined value.

5. An autofocus camera according to claim 1, wherein said focus detector outputs a focus impossibility indication when focus cannot be detected using said first photoelectric conversion unit and cannot be detected using said second photoelectric conversion unit.

8. An autofocus camera according to claim 1, wherein at least one of said first and second photoelectric conversion units includes a plurality of light-receiving elements, and wherein said focus detector has a first mode of operation in which outputs of all of said light-receiving elements can be utilized for obtaining said focus detection result when said attitude detector detects a first camera attitude, and a second mode of operation in which outputs of only part of said light-receiving elements can be utilized for obtaining said focus detection result when said attitude detector detects a second camera attitude.

6. An autofocus camera comprising:

a first photoelectric conversion unit including a plurality of elements to receive subject light from detecting regions which extend along one direction of a photographing image plane and to perform photoelectric conversion;

a second photoelectric conversion unit to receive subject light from at least one detecting region extending along a direction different from said one direction of said photographing image plane and to perform photoelectric conversion;

an attitude detector to detect attitude of the camera;

a focus detector having a first mode of operation in which outputs of all of said light-receiving elements of said first photoelectric conversion units can be utilized for obtaining a focus detection result to be used for focus control, and a second mode of operation in which outputs of only part of said light-receiving elements of said first photoelectric conversion unit can be utilized for obtaining the focus detection result;

a selector to select between said first and second modes of operation in accordance with the detected attitude of the camera; and

a lens driving unit to drive and focus a photographic lens according to the focus detection result obtained by said focus detector.

7. An autofocus camera according to claim 6, wherein said first photoelectric conversion unit is horizontally oriented and said second photoelectric conversion unit is vertically oriented when the camera is in a horizontal attitude.

9. An autofocus camera according to claim 6, wherein said second photoelectric conversion unit includes a plurality of light-receiving elements, and outputs of at least part of the light-receiving elements of said second photoelectric conversion unit can be utilized for obtaining the photodetection result in each of said first and second modes of operation.

10. A method of detecting focus in an autofocus camera, comprising the steps of:

detecting attitude of the camera;

selecting one of a first photoelectric conversion unit and a second photoelectric conversion unit in accordance with a detected attitude of the camera, said first photoelectric conversion unit receiving subject light from a detecting region extended in one direction of a photographic image plane and performing photoelectric conversion, and said second photoelectric conversion unit receiving subject light from a detecting region extended in a direction different from said one direction of said photographic image plane and performing photoelectric conversion;

conducting a first focus detection operation using the selected photoelectric conversion unit;

discriminating based on a result of the focus detection operation whether focus can be detected using the selected photoelectric conversion unit, and, if it is discriminated that focus cannot be detected using the selected photoelectric conversion unit, conducting a second focus detection operation using the other of said first and second photoelectric conversion units; and

driving and focusing a photographic lens in accordance with a focus detection result from the first focus detection operation or the second focus detection operation depending upon whether or not the second focus detection operation is conducted.

11. A method of detecting focus in an autofocus camera, comprising the steps of:

detecting attitude of the camera;

if a first camera attitude is detected, conducting a focus detection operation using outputs of all light-receiving elements of a plurality of light-receiving elements receiving subject light from detecting regions extended in one direction of a photographic image plane to obtain a focus detection result to be used for focus control;

if a second camera attitude is detected, conducting a focus detection operation using only part of said light-receiving elements to obtain the focus detection result; and

driving and focusing a photographic lens in accordance with the focus detection result.