A method of obtaining an image uses a broad dynamic range image sensor is provided. The method comprises: initializing the capacitor and photodiode to a first initialization voltage via conduction of the second and third transistors, then making the second transistor non-conductive to start a first long exposure period of the photodiode. At the end of the first exposure period, the first transistor is made conductive provisionally to initialize the photodiode to a second initialization voltage which is lower that the first initialization voltage to start a second short exposure period. At the end of the second exposure period, photodiode voltage level is stored in the capacitor to be readed via a fourth and a fifth transistor.