I'm asking because usually when I take a shot, I hear the click, sometimes two clicks with slower shutter speeds and a high pitched noise immediately after the second click, similar to the startup noise on the e-pl3. Now sometimes when I take a shot, I hear the click when i press the button, the second click and there is an noticeable interval before the high pitched noise is heard. I first noticed the other day when I took some long exposures. Again this evening, the shutter would sound when I pressed it, then another click depending on the chosen shutter speed and about a second or two before the high pitched noise. I thought it may have had something to do with the IBIS with longer exposures but it was also noticeable with faster shutter speeds, I'd hear a click and an interval before the high pitched noise. It went away after i put it in sequential mode and fired off a few shots at 1/2000s.