Photoelectric-conversion device

A focus-detection device comprising:

• a pair of line-sensor units,
• wherein each line-sensor unit includes a plurality of unit pixels each having a sensor-cell unit that outputs a signal obtained by photoelectric conversion, and a plurality of memory-cell units,
• wherein the focus-detection device writes, in a temporally overlapped manner, a reset noise generated due to initialization of one of the sensor-cell units into each of the corresponding memory-cell units,
• wherein the device further comprises a transfer unit configured to receive a signal from the unit pixel and to transfer the signal to the unit pixel, where the transfer unit performs a difference processing between the signal from the sensor-cell unit, and the reset noise written in the corresponding memory-cell unit and a noise generated in the transfer unit,
• wherein, for a first region of each of the line-sensor units, the focus-detection device performs the difference processing using one of the memory-cell units of each of the unit pixels, and detects the defocusing amount from a second region of each of the line-sensor units, the second region being of a wider region of the line-sensor unit and performs the difference processing through a memory-cell unit different from the one of the memory-cell units of each of the unit pixels.