Camera that engages in a focusing operation through a contrast method

• US 7,158,182 B2
• Filed: 09/26/2002
• Issued: 01/02/2007
• Est. Priority Date: 09/28/2001
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Maeda, Toshiaki, Ohta, Tadashi, Watanabe, Toshimi, Hibino, Hideo
• Primary Examiner(s): Ye; Lin
• Application Number:
  US10/254,881
• Publication Number:
  US 20030063212A1
• Time in Patent Office: 1,559 Days
• Field of Search: 348/345, 348/349, 348/350, 348/354, 396/89, 396/106
• US Class Current: 348/345
• CPC Class Codes: H04N 23/673 based on contrast or high frequency components of image signals, e.g. hill climbing method

Abstract

A camera includes: an image-capturing element that captures a subject image through a photographic lens having a focusing lens; an evaluation value calculation unit that calculates focus evaluation values at a plurality of lens positions assumed by the focusing lens based upon an image-capturing signal output by the image-capturing element; a weighting unit that weights the focus evaluation values calculated by the evaluation value calculation unit in correspondence to the lens positions of the focusing lens assumed when the focus evaluation values are calculated respectively; and a focusing operation unit that performs a focusing operation for the photographic lens based upon the weighted focus evaluation values.

Claims

1. A camera, comprising:

an image-capturing element that captures a subject image through a photographic lens;

an evaluation value calculation unit that calculates focus evaluation values each in correspondence to one of a plurality of focus detection areas that include a central focus detection area set at a center of an image-capturing area at the image-capturing element, based upon image-capturing signals individually output from the image-capturing element each in correspondence to one of the plurality of focus detection areas;

an attitude detection unit that detects a camera attitude;

a weighting unit that weights the plurality of focus detection areas in conformance to results of a detection performed by the attitude detection unit; and

a focusing operation unit that performs a focusing operation for the photographic lens based upon the focus evaluation values corresponding to the plurality of focus detection areas that have been weighted.

2. A camera according to claim 1, wherein:

a greater weight is applied to focus evaluation values corresponding to the central focus detection area and a peripheral focus detection area set above the central focus detection area along a vertical direction in a portrait photographing mode based upon the camera attitude detected by the attitude detection unit.

3. A camera according to claim 1, further comprising:

a photographing mode setting unit that sets a portrait photographing mode, wherein;

a greater weight is applied to focus evaluation values corresponding to the central focus detection area and a peripheral focus detection area set above the central focus detection area along a vertical direction based upon the camera attitude detected by the attitude detection unit, when the portrait photographing mode is set.

4. A camera, comprising:

an image-capturing element that captures a subject image through a photographic lens;

an evaluation value calculation unit that calculates focus evaluation values each in correspondence to one of a plurality of focus detection areas that include a central focus detection area set at a center of an image-capturing area at the image-capturing element, based upon high frequency components of image-capturing signals individually output from the image-capturing element each in correspondence to one of the plurality of focus detection areas;

an attitude detection unit that detects a camera attitude;

a weighting unit that weights the plurality of focus detection areas in conformance to results of a detection performed by the attitude detection unit; and

a focusing operation unit that performs a focusing operation for the photographic lens based upon a peak value of the focus evaluation values corresponding to the plurality of focus detection areas that have been weighted.

5. A camera according to claim 4, wherein:

a greater weight is applied to focus evaluation values corresponding to the central focus detection area and a peripheral focus detection area set above the central focus detection area along a vertical direction in a portrait photographing mode based upon the camera attitude detected by the attitude detection unit.

6. A camera according to claim 4, further comprising:

a photographing mode setting unit that sets a portrait photographing mode, wherein;

a greater weight is applied to focus evaluation values corresponding to the central focus detection area and a peripheral focus detection area set above the central focus detection area along a vertical direction based upon the camera attitude detected by the attitude detection unit, when the portrait photographing mode is set.