There are provided an endoscope system, a processor apparatus for an endoscope system, and a method for operating an endoscope system. In a special observation mode, first illumination light and second illumination light having a spectral property different from a spectral property of the first illumination light and including different-absorption-wavelength light that has different absorption coefficients for oxygenated hemoglobin and reduced hemoglobin are alternately emitted to a test body while a turn-off period is interposed. A first image capture signal is read from the image sensor during the turn-off period after emission of the first illumination light, and a second image capture signal is read from the image sensor during the turn-off period after emission of the second illumination light. Here, a second read time taken to read the second image capture signal is made shorter than a first read time taken to read the first image capture signal.
