An image sensor for an electronic imaging device includes an array of pixels. Each pixel (2) includes a switch device (8) having a first switch input, a second switch input and a switch output that is switchably connected to the first switch input. The switch device (8) is constructed and arranged to disconnect the switch output from the first switch input at a capture moment determined by comparing a first input signal VIn1 and a second input signal VIn2. A photosensor device (4) has a photosensor output that is connected to the first switch input. A first signal -generator (18) generates alternately a reference signal Vref and a reference calibration signal Vrefcal, and is connected to the second switch input. A second signal generator (30) generates a photosensor reference signal Vpcal, and is switchably connected to the first switch input. A readout circuit (10) is arranged to capture the switch output signal Vs at the capture moment and provide an output signal that is related to the switch output signal.
