In shutter-priority AE (mode S), you select the shutter speed and let the camera choose the aperture. Set aperture to [A] and rotate the shutter speed dial to the desired setting.
Shutter speed: 1/1000 s
Shutter speed can also be adjusted in increments of 1/3 EV by rotating the command dial.
If the correct exposure can not be achieved at the selected shutter speed, aperture will be displayed in red when the shutter button is pressed halfway.
If the subject is outside the metering range of the camera, the aperture display will show “– – –”.