An imaging apparatus comprising: a cell array having a plurality of groups arranged across a plurality of rows and a plurality of columns, each of the groups including a photoelectric converting unit, a signal holding unit, an amplifying unit (7, 17) having an input node (5, 15), a first transfer unit having an electrical path between the photoelectric converting unit and the signal holding unit, and a second transfer unit having an electrical path between the signal holding unit and the input node (5, 15); and control means configured to control the plurality of groups, wherein the control means is configured to synchronize the plurality of groups to start and to complete a transfer of a signal from the photoelectric converting unit to the signal holding unit performed by the first transfer unit; and wherein at least one of the plurality of groups further has capacitance changing means configured to change a capacitance value of the input node (5, 15) therein, characterized in that the photoelectric converting unit is configured to accumulate a signal during a first accumulation period and during a second accumulation period different from the first accumulation period and longer than the first accumulation period; wherein, in response to a change of the input node (5, 15) to have a first capacitance value performed by the capacitance changing means, a signal corresponding to one of the first accumulation period and the second accumulation period, is transferred from the second transfer unit to the input node (5, 15); and wherein, in response to a change of the input node (5, 15) to have a second capacitance value lower than the first capacitance value performed by the capacitance changing means, a signal corresponding to the other of the first accumulation period and the second accumulation period, is transferred from the second transfer unit to the input node (5, 15). a cell array having a plurality of groups arranged across a plurality of rows and a plurality of columns, each of the groups including a photoelectric converting unit, a signal holding unit, an amplifying unit (7, 17) having an input node (5, 15), a first transfer unit having an electrical path between the photoelectric converting unit and the signal holding unit, and a second transfer unit having an electrical path between the signal holding unit and the input node (5, 15); and control means configured to control the plurality of groups, wherein the control means is configured to synchronize the plurality of groups to start and to complete a transfer of a signal from the photoelectric converting unit to the signal holding unit performed by the first transfer unit; and wherein at least one of the plurality of groups further has capacitance changing means configured to change a capacitance value of the input node (5, 15) therein, characterized in that the photoelectric converting unit is configured to accumulate a signal during a first accumulation period and during a second accumulation period different from the first accumulation period and longer than the first accumulation period; wherein, in response to a change of the input node (5, 15) to have a first capacitance value performed by the capacitance changing means, a signal corresponding to one of the first accumulation period and the second accumulation period, is transferred from the second transfer unit to the input node (5, 15); and wherein, in response to a change of the input node (5, 15) to have a second capacitance value lower than the first capacitance value performed by the capacitance changing means, a signal corresponding to the other of the first accumulation period and the second accumulation period, is transferred from the second transfer unit to the input node (5, 15).