Focus adjustment apparatus and focus adjustment method

A focus adjustment apparatus comprising:

• a focus lens;
• a focus lens driver configured to drive the focus lens in an optical axis direction;
• an image pickup unit configured to generate an image signal by converting image light incident through the focus lens into an electrical signal;
• an Auto Focus (AF) evaluation value deriver configured to derive AF evaluation values respectively corresponding to a plurality of focus lens positions at each of a plurality of first focus areas including at least one area of a scene of the image pickup unit using image signals respectively corresponding to the plurality of focus lens positions and first focus areas;
• and
• a peak value determiner configured to determine peak AF evaluation values respectively corresponding to the plurality of first focus areas according to the AF evaluation values respectively corresponding to each of the plurality of first focus areas;
• a determiner configured to determine at least one condition;
• a focus area setting unit configured to set a focus area, which is greater than the first focus area and has a shape of which a width of an upper part is narrow, according to the determined condition;
• and
• a controller configured to control movement of the focus lens to adjust a focus on an image signal corresponding to the set focus area.

A focus adjustment method comprising:

• generating an image signal by converting image light incident through a focus lens into an electrical signal;
• deriving a plurality of Auto Focus (AF) evaluation values using image signals respectively corresponding to a plurality of first lens positions;
• and
• determining a peak AF evaluation value according to the AF evaluation values,
• determining whether the peak AF evaluation value is low by comparing the peak AF evaluation value to a reference peak value;
• setting a focus area in a shape of which a width of an upper part is narrow according to the determined condition, wherein the setting of the focus area comprises if the peak AF value is not low setting a first focus area, and if the peak value is low setting a second focus area which is greater than the first focus area and has a shape of which a width of an upper part is narrow;
• and
• moving the focus lens to adjust a focus on an image signal corresponding to the set focus area.

A focus adjustment method comprising:

• generating an image signal by converting image light incident through a focus lens into an electrical signal;
• determining at least one condition;
• setting a focus area in a shape of which a width of an upper part is narrow according to the determined condition;
• moving the focus lens to adjust a focus on an image signal corresponding to the set focus area;
• deriving Auto Focus (AF) evaluation values respectively corresponding to a plurality of focus lens positions at each of a plurality of first focus areas using image signals respectively corresponding to the plurality of focus lens positions and first focus areas;
• and
• determining peak AF evaluation values respectively corresponding to the plurality of first focus areas from the AF evaluation values respectively corresponding to the plurality of first focus areas.

A focus adjustment apparatus comprising:

• a focus lens;
• a focus lens driver configured to drive the focus lens in an optical axis direction;
• an image pickup unit configured to generate an image signal by converting image light incident through the focus lens into an electrical signal;
• a determiner configured to determine at least one condition;
• a focus area setting unit configured to set a first focus area and a second focus area according to the determined condition;
• and
• a controller configured to control movement of the focus lens to adjust a focus on an image signal corresponding to one of the first focus area and the second focus area,
• wherein the second focus area is an area which expands vertically from the first focus area.