->> I was shooting a snow skiing competition this weekend with my Mark IV and set the white balance to "sunny." After the first race, I decided to switch to AWB because the sun was going in and out. When I processed the photos, the exposure was fine but the first race came out all black and white. The second race came out in color. I have never had this happen in my life. All I can figure is that the camera saw the white snow and overcompensated. Does that make sense? Any other explanation? The only thing I changed was the white balance.