Thinking about getting a flash unit for my D40. The only thing I want to use flash for is for bounce flash when I'm indoors. Maybe fill flash but that will be rarer. Ken Rockwell seems to favor the sb400 (my other alternative would be the sb600) just for the size and since I don't need fancy slave + master remote functions and w/e, sb400 looks fine for me. My main question (aside from is sb400 a good choice) is regarding the proper exposures when using flash. Does the camera know I'm about to fire a flash? I shoot in A mode... so do I need to manually set up exposure compensation/ flash comp?? If so... how do I know how much to go down or up? Thanks.