Two things I've always been a bit nervous of with shots directly into the sun (sunsets):
1) How safe is it to look through the viewfinder when you have say a 200mm lens or longer pointed at a sunset? 2) Is there any chance of damaging the shutter curtains or the CCD in the *istD? Even back in the days of film I sometimes worried about whether the sun could damage the shutter curtains like a magnifying glass can burn a hole in paper and consequently always took the shot as quickly as I could.
