I'm learning to use flash with my Olympus EM5 with the stock flash and with a Metz flash for Olympus and Panasonic cameras. I am learning the basics of flash with this camera for the first time. Well my question is "Why when I use 2nd curtain, does it fire once, in the beginning and again at the end?" , shouldn't it just fire at the end? I thought 2nd curtain is like rear curtain and only fires at the very end. Not the beginning and the end. I noticed 2nd curtain fires twice with my Metz and with the stock flash that comes with EM5.