Image capturing system and control method of the same

A method for controlling an image capturing system including an image-capturing unit and a main unit and capable of serial communication between the image-capturing unit and the main unit;

• wherein the main unit generates a first clock signal, converts data to be transmitted to the image-capturing unit into serial data using the first clock signal, and transmits the serial data to the image-capturing unit;
• and
• wherein the image-capturing unit detects a serial transfer frequency from the serial signal received from the main unit, returns the first clock signal, generates a second clock signal from the recovered first clock signal, converts a taken image into serial data using the second clock signal, and transmits the serial data to the main unit;
• and
• wherein the main unit returns the second clock signal from the serial data transmitted from the image-capturing unit, and synchronizes with the image-capturing unit by utilizing the recovered second clock signal for generating the first clock signal.