High dynamic range imaging systems having differential photodiode exposures

Image sensors may include an array of photodiodes arranged in groups of adjacent photodiodes that generate charge in response to same-colored light. The image sensor may generate high-dynamic-range (HDR) images. To establish an effective exposure ratio between sets of photodiodes on the array for generating HDR images, microlenses may be formed over some photodiodes in a checkerboard pattern and may have portions that extend over other photodiodes in the array. Control circuitry may control photodiodes in each group to perform pulsed integration in which charge transfer control signals are intermittently pulsed for those photodiodes. A substantially opaque element may be formed over photodiodes in each of the groups such that the corresponding photodiodes generate signals in response to crosstalk. In this way, different effective exposures may be established across the array, allowing for HDR images to be generated without motion artifacts and with super-pixel resolution.