An image sensor includes a first chip including a first substrate having a plurality of pixels, and a first wiring structure, each of the plurality of pixels including first and second isolated photodiodes; a second chip including a second wiring structure, and a second substrate; and a third chip including a third wiring structure, and a third substrate having logic devices, wherein each of the plurality of pixels includes a first floating diffusion node on the first photodiode, a second floating diffusion node on the second photodiode, a third floating diffusion node between the first and second floating diffusion nodes on the second photodiode, and a first switching transistor on the second substrate, and wherein the first switching transistor is connected to the first floating diffusion node through the first and second wiring structures, and the third floating diffusion node through the first and second wiring structures.