Imaging apparatus and focus control method based on a number of automatic focus scan stages, and recording medium storing a program for executing such a method

An imaging apparatus, comprising:

• focus control means for sequentially moving a focal lens to each of a plurality of positions and acquiring from an image signal an automatic focus evaluation value, which is acquired in correspondence with sharpness of an edge portion of a photographing object image, and stopping said focal lens at a focal point being set to a maximum point of the automatic focus evaluation value so as to perform an automatic focusing operation;
• and
• range control means for causing said focus control means to perform the automatic focusing operation by limiting a movable range of the focal lens to a range narrower than an entire focus range with an immediately preceding focal point so as to include a smaller number of the positions, when, at a time of taking a picture, the number of the positions to be used by the focus control means to move the focal lens for acquiring the automatic focus evaluation value is larger than a predetermined number and a predetermined condition is satisfied, wherein
• said range control means causes said focus control means to perform the automatic focusing operation by the entire focus range including the number of the positions, when, at the time of taking the picture, at least one of a following criteria is satisfied, the number of the positions to be used by the focus control means to move the focal lens for acquiring the automatic focus evaluation value is smaller than the predetermined number and the predetermined condition is not satisfied.

A focus control method, comprising:

• performing an automatic focusing operation by sequentially detecting a focal point while moving a focal lens to each of a plurality of positions, which constitutes at least a part of an imaging optical system of said imaging apparatus, and stopping the focal lens at the focal point;
• and
• causing said automatic focusing operation to be performed by limiting a movable range of the focal lens to a range narrower than an entire focus range with an immediately preceding focal point set as a reference, so as to include a smaller number of the positions, when, at a time of taking a picture, the number of the positions to be used to move the focal lens for detecting the focal point is larger than a predetermined number and a predetermined condition is satisfied;
• and
• causing said automatic focusing operation to be performed by the entire focus range including the number of the positions, when, at the time of taking the picture, at least one of a following criteria is satisfied, the number of the positions to be used to move the focal lens for detecting the focal point is smaller than the predetermined number and the predetermined condition is not satisfied.

A focus control method, comprising:

• sequentially moving a focal lens to each of a plurality of positions and acquiring from an image signal an automatic focus evaluation value, which is acquired in correspondence to sharpness of an edge portion of a photographing object image while moving a focal lens, which constitutes at least a part of an imaging optical system;
• controlling an automatic focusing operation by stopping said focal lens at a focal point set as a maximum point of the automatic focus evaluation value;
• and
• causing said automatic focusing operation to be performed by limiting a movable range of the focal lens to a range narrower than an entire focus range with an immediately preceding focal point set as a reference, so as to include a smaller number of the positions, when, at a time of taking a picture, the number of the positions to be used to move the focal lens for acquiring the automatic focus evaluation value is larger than a predetermined number and a predetermined condition is satisfied;
• and
• causing said automatic focusing operation to be performed by the entire focus range including the number of the positions, when, at the time of taking the picture, at least one of a following criteria is satisfied, the number of the positions to be used to move the focal lens for acquiring the automatic focus evaluation value is smaller than the predetermined number and the predetermined condition is not satisfied.

A computer readable recording medium storing a program for causing a computer to perform a focus control method comprising:

• performing an automatic focusing operation by sequentially detecting a focal point while moving a focal lens to each of a plurality of positions, which constitutes at least a part of an imaging optical system of said imaging apparatus, and stopping the focal lens at the focal point;
• and
• causing said automatic focusing operation to be performed by limiting a movable range of the focal lens to a range narrower than an entire focus range with an immediately preceding focal point set as a reference, so as to include a smaller number of the positions, when, at a time of taking a picture, the number of the positions to be used to move the focal lens for detecting the focal point is larger than a predetermined number and a predetermined condition is satisfied;
• and
• causing said automatic focusing operation to be performed by the entire focus range including the number of the positions, when, at the time of taking the picture, at least one of a following criteria is satisfied, the number of the positions to be used to move the focal lens for detecting the focal point is smaller than the predetermined number and the predetermined condition is not satisfied.

A computer readable recording medium storing a program for causing a computer to perform a focus control method comprising:

• sequentially moving a focal lens to each of a plurality of positions and acquiring from an image signal an automatic focus evaluation value, which is acquired in correspondence to sharpness of an edge portion of a photographing object image while moving a focal lens, which constitutes at least a part of an imaging optical system;
• controlling an automatic focusing operation by stopping said focal lens at a focal point set as a maximum point of the automatic focus evaluation value;
• and
• causing said automatic focusing operation to be performed by limiting a movable range of the focal lens to a range narrower than an entire focus range with an immediately preceding focal point set as a reference, so as to include a smaller number of the positions, when, at a time of taking a picture, the number of the positions to be used to move the focal lens for acquiring the automatic focus evaluation value is larger than a predetermined number and a predetermined condition is satisfied;
• and
• causing said automatic focusing operation to be performed by the entire focus range including the number of the positions, when, at the time of taking the picture, at least one of a following criteria is satisfied, the number of the positions to be used to move the focal lens for acquiring the automatic focus evaluation value is smaller than the predetermined number and the predetermined condition is not satisfied.

An imaging apparatus, comprising:

• a detecting unit configured to sequentially detect a focal point while moving a focal lens to each of a plurality of positions and stopping the focal lens at the focal point so as to perform an automatic focusing operation;
• and
• a controller configured to cause the detecting unit to perform the automatic focusing operation by limiting a movable range of the focal lens to a range narrower than an entire focus range with an immediately preceding focal point, so as to include a smaller number of the positions, when, at a time of taking a picture, the number of the positions to be used by the detecting unit to move the focal lens to detect the focal point is larger than a predetermined number and a predetermined condition is satisfied, wherein
• the controller is further configured to cause the detecting unit to perform the automatic focusing operation by the entire focus range including the number of the positions, when, at the time of taking the picture, at least one of a following criteria is satisfied, the number of the positions to be used by the detecting unit to move the focal lens to detect the focal point is smaller than the predetermined number and the predetermined condition is not satisfied.

An imaging apparatus, comprising:

• an acquisition unit configured to sequentially move a focal lens to each of a plurality of positions and to acquire from an image signal an automatic focus evaluation value, which is acquired in correspondence with a sharpness of an edge portion of a photographing object image, and to stop the focal lens at a focal point set to a maximum point of the automatic focus evaluation value so as to perform an automatic focusing operation;
• and
• a controller configured to cause the acquisition unit to perform the automatic focusing operation by limiting a movable range of the focal lens to a range narrower than an entire focus range with an immediately preceding focal point so as to include a smaller number of the positions, when, at a time of taking a picture, the number of the positions to be used by the acquisition unit to move the focal lens to acquire the automatic focus evaluation value is larger than a predetermined number and a predetermined condition is satisfied, wherein
• the controller is further configured to cause the acquisition unit to perform the automatic focusing operation by the entire focus range including the number of the positions, when, at the time of taking the picture, at least one of a following criteria is satisfied, the number of the positions to be used by the acquisition unit to move the focal lens to acquire the automatic focus evaluation value is smaller than the predetermined number and the predetermined condition is not satisfied.