A single-exposure high dynamic range (HDR) image sensor includes a first photodiode and a second photodiode, with a smaller full-well capacity than the first photodiode, disposed in a semiconductor material. The image sensor also includes a first floating diffusion disposed in the semiconductor material and a first transfer gate coupled to the first photodiode to transfer first image charge accumulated in the first photodiode into the first floating diffusion. A second floating diffusion is disposed in the semiconductor material and a second transfer gate is coupled to the second photodiode to transfer second image charge accumulated in the second photodiode into the second floating diffusion. An attenuation layer is disposed between the second photodiode and image light directed towards the single-exposure HDR image sensor to block a portion of the image light from reaching the second photodiode.