An image pickup system that performs image pickup control of a rolling shutter type such that an all line exposure period and a non-all line exposure period are generated and controls a light source of illumination light to increase or decrease, in a first light adjustment mode, while maintaining a light amount of the illumination light in a first period during the all line exposure period at a predetermined level, a light amount of the illumination light during a second period including the all line exposure period other than the first period and the non-all line exposure period compared with an immediately preceding second period.