An image sensor includes pixels. Each pixel includes a first photodiode, a second photodiode, an overflow transistor having one end connected to the second photodiode, a storage capacitor, a capacitor connection transistor having a first end connected to the storage capacitor and a second end connected to the second photodiode, a first transistor connected to the first photodiode, a second transistor connected to the second photodiode, a first floating node connected to the first photodiode through the first transistor, a second floating node connected to the second photodiode through the second transistor, a conversion gain transistor between the first floating node and the second floating node, a driving transistor connected to the first photodiode, and a selection transistor connected to the driving transistor. The first photodiode has a larger light receiving area than the second photodiode.