An imaging system may include an image sensor having an array of dual gain pixels. Each pixel may be operated using an improved three read method and an improved four read method such that all signals are read in a high gain configuration in order to prevent electrical offset in signal levels. Each pixel may be operated using an improved three read, two analog to digital conversion (ADC) method in which a frame buffer is used to store calibration data. Each pixel may be operated using an improved three read, three ADC method in which no frame buffer is required. A high dynamic range image signal may be produced for each pixel based on signals read from the pixel and on light conditions.