Imaging apparatus, imaging method, and focus control apparatus

An imaging method for an imaging apparatus including a controller having a central processing unit coupled to a memory storing data of a trace curve corresponding to a distance to the subject before the magnification change operation is performed and data of a trace curve corresponding to a distance to the subject located at infinity, a zooming lens that moves in an optical axis direction to perform magnification change operation and a focusing lens that moves in the optical axis direction to perform focus adjustment and for driving the focusing lens in accordance with one of the data of the trace curve corresponding to a distance to the subject before the magnification change operation is performed and data of the trace curve corresponding to a distance to the subject located at infinity, the method comprising:

• evaluating, during the magnification change operation, based on a rate of change in a number of high-luminance pixels at which the number of high-luminance pixels in an output image from the imaging apparatus changes with the zoom magnification, whether or not the focusing lens is driven by a motor in accordance with the trace curve corresponding to the distance to the subject before the magnification change operation is performed or the trace curve corresponding to the distance to the subject located at infinity,
• wherein when the magnification change operation is a zoom-in operation from a low magnification to a high magnification, the rate of change in the number of high-luminance pixels at which the number of high-luminance pixels in an output image from the imaging apparatus changes with the zoom magnification is compared with a threshold, and when the rate of change in the number of high-luminance pixels is greater than the threshold, the focusing lens is moved in accordance with the trace curve corresponding to the distance to the subject before the magnification change operation is performed or the trace curve corresponding to the distance to the subject located at infinity.

A focus control apparatus including a zooming lens that moves in an optical axis direction to perform magnification change operation and a focusing lens that moves in the optical axis direction to perform focus adjustment and the focusing lens is driven in accordance with a trace curve corresponding to the distance to a subject, the focus control apparatus comprising:

• a controller, having a central processing unit coupled to a memory storing data of a trace curve corresponding to a distance to the subject before the magnification change operation is performed and data of a trace curve corresponding to a distance to the subject located at infinity, that evaluates, during the magnification change operation, based on a rate of change in a number of high-luminance pixels at which the number of high-luminance pixels in an output image from an imaging apparatus changes with the zoom magnification, whether or not the focusing lens is driven by a motor in accordance with the trace curve corresponding to the distance to the subject before the magnification change operation is performed or the curve corresponding to the distance to the subject located at infinity,
• wherein when the magnification change operation is a zoom-in operation from a low magnification to a high magnification, the rate of change in the number of high-luminance pixels at which the number of high-luminance pixels in an output image from the imaging apparatus changes with the zoom magnification is compared with a threshold, and when the rate of change in the number of high-luminance pixels is greater than the threshold, the focusing lens is moved in accordance with the trace curve corresponding to the distance to the subject before the magnification change operation is performed or the trace curve corresponding to the distance to the subject located at infinity.