I'm getting the guide camera up and running, but can't see to focus, since the camera is overexposing the image. I see Gain (1-100...set to 1), Offset )1-20, setting at 1 or 20 doesn't seem to matter),  Bandwidth (40-100...set at 40), and Flip, OverCLK,  and 4 other options, all set to zero. How do I reduce the shutter speed so I can see to focus in the daylight?