PHOTOGRAPHING METHOD AND APPARATUS

摘要

A digital camera is provided with a frequency component extraction unit, an AR evaluation value acquisition unit, a variation calculation unit, and a moving speed control unit. The frequency component extraction unit has first and second filters, and extracts first and second spatial frequency components. The AF evaluation value acquisition unit integrates the first and second spatial frequency components to acquire first and second AF evaluation values. The variation calculation unit calculates a first variation corresponding to first-order differentiation of the first AF evaluation value, a second variation corresponding to first-order differentiation of the second AF evaluation value, and a third variation corresponding to second-order differentiation of the second AF evaluation value. The moving speed control unit controls the moving speed of a focus lens at the time of an AF operation based on the rates of increase or decrease of the first to third variations.

主权项

1. A photographing apparatus comprising:
a focus lens; a lens drive unit which moves the focus lens in an optical axis direction; an imaging unit which images an object at an interval of a predetermined time through the focus lens moving in the optical axis direction, and generates a plurality of pieces of image data; a frequency component extraction unit which extracts a spatial frequency component from each piece of image data using a first filter and a second filter as high pass filters, a cutoff frequency of the first filter being higher than a cutoff frequency of the second filter; an AF evaluation value acquisition unit which integrates the spatial frequency component extracted by the first filter to acquire a first AF evaluation value, and integrates the spatial frequency component extracted by the second filter to acquire a second AF evaluation value; an arithmetic unit which subtracts a value obtained by multiplying or adding a predetermined constant to the first AF evaluation value from the second AF evaluation value to calculate an arithmetic value; a variation calculation unit which calculates a variation of the arithmetic value at an interval of the predetermined time; a moving speed control unit which controls a moving speed of the focus lens by the lens drive unit based on the variation; and a focal position detection unit which detects a focal position of the focus lens based on at least one of the first AF evaluation value and the second AF evaluation value.