Imaging device and camera system, and driving method of imaging device

A camera system comprising:

• an imaging device including:
• a photoelectric converter that includes a first electrode, a second electrode, and a photoelectric conversion layer located between the first electrode and the second electrode,
• a voltage supply circuit, and
• an output circuit that is coupled to the second electrode, the output circuit being configured to output a signal that corresponds to a potential of the second electrode;
• and
• a light quantity detector that detects a quantity of light incident on the photoelectric converter, wherein
• the photoelectric converter has photoelectric conversion characteristics in which a first rate of change is greater than a second rate of change, the first rate of change being a rate of change of a photoelectric conversion efficiency of the photoelectric converter with respect to a bias voltage applied between the first electrode and the second electrode when the bias voltage is in a first voltage range, the second rate of change being a rate of change of the photoelectric conversion efficiency of the photoelectric converter with respect to the bias voltage when the bias voltage is in a second voltage range that is higher than the first voltage range, and
• the voltage supply circuit
• applies a voltage to one of the first electrode and the second electrode to cause a potential difference between the first electrode and the second electrode to be a first potential difference, in a case where the quantity of light detected by the light quantity detector is greater than or equal to a first quantity of light, and,
• applies a voltage to the one of the first electrode and the second electrode to cause the potential difference between the first electrode and the second electrode to be a second potential difference that is greater than the first potential difference, in a case where the quantity of light detected by the light quantity detector is less than a second quantity of light that is less than or equal to the first quantity of light.