Image sensor and electronic camera

An image sensor comprising:

• a pixel unit including a plurality of pixels and in which a first pixel and a second pixel are arranged along a row direction, a third pixel is arranged in line with the first pixel in a colunm direction, and a fourth pixel is arranged in line with the first pixel in the row direction, the first pixel (i) including a first photoelectric conversion unit that converts light to a charge and (ii) outputting a first signal based on the charge photoelectrically converted by the first photoelectric conversion unit, the second pixel (i) including a second photoelectric conversion unit that converts light to a charge and (ii) outputting a second signal based on the charge photoelectrically converted by the second photoelectric conversion unit, the third pixel (i) including a third photoelectric conversion unit that converts light to a charge and (i) outputting a third signal based on the charge photoelectrically converted by the third photoelectric conversion unit, and the fourth pixel (i) including a fourth photoelectric conversion unit that converts light to a charge and (ii) outpatting a fourth signal based on the charge photoelectrically converted by the fourth photoelectric conversion unit;
• a first signal line electrically connected to the first pixel;
• a second signal line electrically connected to the second pixel;
• a third signal line electrically connected to the fourth pixel;
• a circuit unit including a first A/D conversion unit that is electrically connected to the first signal line and converts an analog signal into a digital signal, and a second A/D conversion unit that is electrically connected to the second signal line and converts an analog signal into a digital signal;
• a first connection unit for electrically connecting the first pixel and the second signal line and that includes a first switch unit arranged within the pixel unit between two adjacent pixels of the plurality of pixels included in the pixel unit;
• a second connection unit for electrically connecting the third pixel and the third signal line and including a second switch unit arranged within the pixel unit, and
• a control unit that controls, during a signal readout period for the first and second pixels, the first pixel and the second pixel so as to cause the first signal to be output from the first pixel to the second signal line via the first connection unit, and so as to cause the second signal not to be output from the second pixel, wherein
• the control unit controls, during the signal readout period, the third pixel so as to cause the third signal to be output from the third pixel to the third signal line via the second connection unit.