Imaging apparatus

An imaging apparatus comprising:

• a pixel configured to generate a signal;
• an A/D conversion unit configured to generate a digital signal based on the signal of the pixel, the A/D conversion unit including a reference signal generating circuit, a comparator and a counter, wherein the reference signal generating circuit is configured to generate a plurality of reference signals, including a first reference signal having a first level changing ratio depending on time and a second reference signal having a second level changing ratio depending on time the second level changing ratio being larger than the first level changing ratio;
• a selecting circuit configured to select a reference signal from the plurality of reference signals including the first reference signal and the second reference signal, and to supply the reference signal to the comparator,
• wherein the comparator is configured to compare a base signal based on the signal generated by the pixel at a reset state with the first reference signal supplied from the selecting circuit, and to compare an effective signal based on the signal generated by the pixel at a non-reset state with the second reference signal supplied from the selecting circuit,
• wherein the counter is configured to obtain a first count value representing a time until an inversion of a magnitude relation between the base signal and the first reference signal occurs, and configured to obtain a second count value representing a time until an inversion of a magnitude relation between the effective signal and the second reference signal occurs;
• and
• a correcting unit configured to correct a difference of resolutions of the first and second count values.