An image sensor, comprising: a first storage unit, a second storage unit, a comparator having a first electrode and a second electrode connectable to the first and second storage units (213, 211), a third storage unit for storing a predetermined average reset signal, wherein the third storage unit is connectable to the second electrode of the comparator, and a plurality of switch units including: a first switch unit (201, 203) for switching applied image signals to be stored in the first and second storage units (213, 211), a second switch unit connected to the first and second storage units (213, 211), and a third switch unit constructed to connect the third storage unit to the second electrode of the comparator characterized in that in a wider dynamic range mode of operation: - the first storage unit stores a first image signal; - the second storage unit stores a second image signal, the first and second image signals (D1, D2) having different exposure times; - the second switch unit connects the first and second storage units (213, 211) for equalizing the first and second image signals (D1, D2) stored in the first and second storage units (213, 211); - the resulting equalized signal is transmitted to the first electrode of the comparator; and - the third switch unit connects the third storage unit to the second electrode of the comparator to apply the predetermined average reset signal to the second electrode of the comparator; and in a normal mode of operation: - the first storage unit stores a reset signal; - the second storage unit stores an image signal; and - the stored reset signal and the stored image signal are applied to the electrodes of the comparator. a first storage unit, a second storage unit, a comparator having a first electrode and a second electrode connectable to the first and second storage units (213, 211), a third storage unit for storing a predetermined average reset signal, wherein the third storage unit is connectable to the second electrode of the comparator, and a plurality of switch units including: a first switch unit (201, 203) for switching applied image signals to be stored in the first and second storage units (213, 211), a second switch unit connected to the first and second storage units (213, 211), and a third switch unit constructed to connect the third storage unit to the second electrode of the comparator characterized in that in a wider dynamic range mode of operation: - the first storage unit stores a first image signal; - the second storage unit stores a second image signal, the first and second image signals (D1, D2) having different exposure times; - the second switch unit connects the first and second storage units (213, 211) for equalizing the first and second image signals (D1, D2) stored in the first and second storage units (213, 211); - the resulting equalized signal is transmitted to the first electrode of the comparator; and - the third switch unit connects the third storage unit to the second electrode of the comparator to apply the predetermined average reset signal to the second electrode of the comparator; and in a normal mode of operation: - the first storage unit stores a reset signal; - the second storage unit stores an image signal; and - the stored reset signal and the stored image signal are applied to the electrodes of the comparator. a first switch unit (201, 203) for switching applied image signals to be stored in the first and second storage units (213, 211), a second switch unit connected to the first and second storage units (213, 211), and a third switch unit constructed to connect the third storage unit to the second electrode of the comparator characterized in that in a wider dynamic range mode of operation: - the first storage unit stores a first image signal; - the second storage unit stores a second image signal, the first and second image signals (D1, D2) having different exposure times; - the second switch unit connects the first and second storage units (213, 211) for equalizing the first and second image signals (D1, D2) stored in the first and second storage units (213, 211); - the resulting equalized signal is transmitted to the first electrode of the comparator; and - the third switch unit connects the third storage unit to the second electrode of the comparator to apply the predetermined average reset signal to the second electrode of the comparator; - the first storage unit stores a first image signal; - the second storage unit stores a second image signal, the first and second image signals (D1, D2) having different exposure times; - the second switch unit connects the first and second storage units (213, 211) for equalizing the first and second image signals (D1, D2) stored in the first and second storage units (213, 211); - the resulting equalized signal is transmitted to the first electrode of the comparator; and - the third switch unit connects the third storage unit to the second electrode of the comparator to apply the predetermined average reset signal to the second electrode of the comparator; and in a normal mode of operation: - the first storage unit stores a reset signal; - the second storage unit stores an image signal; and - the stored reset signal and the stored image signal are applied to the electrodes of the comparator. - the first storage unit stores a reset signal; - the second storage unit stores an image signal; and - the stored reset signal and the stored image signal are applied to the electrodes of the comparator.