Imaging device

An imaging device, comprising:

• a pixel circuit including a photoelectric conversion unit, a first electric-charge holding unit, a second electric-charge holding unit, a floating diffusion, a transfer circuit configured to transfer electric charges from the photoelectric conversion unit to the floating diffusion either through the first electric-charge holding unit or through the second electric-charge holding unit, and an output circuit configured to output an analog pixel signal having a signal voltage based on an amount of the electric charges transferred to the floating diffusion;
• an analog-to-digital converting circuit configured to perform analog-to-digital conversion on a decrease in the signal voltage;
• and
• a control unit,
• wherein the control unit:
• causes the transfer circuit to transfer first electric charges, generated by the photoelectric conversion unit in a first light-exposure time period, from the photoelectric conversion unit to the first electric-charge holding unit, to transfer second electric charges, generated by the photoelectric conversion unit in a second light-exposure time period shorter than the first light-exposure time period, from the photoelectric conversion unit to the second electric-charge holding unit, and to transfer the first electric charges from the first electric-charge holding unit to the floating diffusion and then to transfer the second electric charges from the second electric-charge holding unit to the floating diffusion;
• and
• causes the analog-to-digital converting circuit to perform analog-to-digital conversion on a decrease selected from a first decrease in the signal voltage observed when the first electric charges and the second electric charges are transferred to the floating diffusion and a second decrease in the signal voltage observed when the second electric charges are transferred to the floating diffusion.