A zoom adjustment system, comprising a touch panel, a course detector, and a first zoom adjuster, is provided. The touch panel has an input surface. The touch panel detects a certain location on the input surface when it is touched. The touch panel detects a touched location. The course detector detects a course traced on the input surface by the touched location when the touched location is moved about on the input surface while maintaining continuous contact with the input surface. The first zoom adjuster adjusts a magnification of a photographic optical system according to the traced course detected by the course detector.