To make Flying-Adder architecture even more powerful, a new concept, time-average-frequency, is incorporated into the clock generation circuitry. There is described an image capturing apparatus which employs the step zooming method with many steps in a unique configuration and which has advantages such as high image quality, small-size, light weight, low power consumption and low price. The method further comprises a primary, a secondary and a tertiary synchronization code in each said predetermined number of time slots.