Patent ID: 6603929
Filing Date: 2003-08-05
Classification: G03B

Abstract:
A camera system comprising:an image-taking optical system, which forms a subject image from the light flux that has entered the image-taking optical system; a first focus detection unit, which detects the focusing condition of said image-taking optical system; a second focus detection unit, which detects the focusing condition of said image-taking optical system at a higher precision than said first focus detection unit; a stepping motor, which drives a focus lens included in said image-taking optical system; a control circuit, which selectively uses information based on the output from said first focus detection unit and information based on the output from said second focus detection unit to control said stepping motor; and a rotation detector, which detects the rotation phase of said stepping motor; wherein said control circuit performs closed loop control, based on the output of said rotation detector, when controlling said stepping motor using the information based on the output of said first focus detection unit, and performs open control for driving said stepping motor a predetermined number of steps at a time, when controlling said stepping motor using the information based on the output of said second focus detection unit.