An imaging element comprising: an imaging unit that has: a plurality of groups each including at least one pixel; and a plurality of signal readout units that are each provided to each of the groups and read out a signal from the pixel; and a control unit that controls the signal readout unit in at least one group among the plurality of groups is provided. Each of the plurality of groups may include a plurality of the pixels. The control unit may select at least one group among the plurality of groups and control the signal readout unit by using a control parameter that is different from a control parameter that is used for another group among the plurality of groups.