Very intermittent flashes of light in the EVF ? Has anyone had / heard of seeing very intermittent flashes of light while looking through the NEX-7 view finder? Occasional just a very fast 'flash' of light...(like a flash unit going off)...usually just a sliver across the top edge, occasionally even a sliver of the image being viewed. Does not seem to be "lens dependent" as I'm pretty sure its happened on different lenses...but am going to start recording specifics from now to be certain. Anyone heard of this...know anything about it?