I am a new user and am lost concerning the bracketing button. When I press and hold the BKT button, it does not allow me to choose the # of frames or exposure steps. I suspect it is something simple, but will appreciate any input. When adjusting the Sub-command dial, I get the following readings: Auto, 1.0, 2.0, 3.0. When adjusting the Main-Command dial I get the following readings: Blank, HDR, HDR + L (upper right corner. Suggestions? Insights?