After numerous glitches and lockups-most solved by removing the battery then re-installing- the camera has finally had a serious nervous breakdown. Switched lenses to the 20 MM and the camera locked. Switched back to the 12-35 normally on the camera and it remained locked up. EVF is black but the info icons are displayed. Shutter will not fire. In shutter priority the shutter speeds are displayed but the aperture is a blinking "-.-" symbol. If I remove the lens the EVF lights up with an out of focus but bright display and the shutter fires. This is the second time for this and the first time it cured itself after simply sitting overnight. Not this time. Any thoughts? Is there some menu I am missing about indexing to lenses?