XF1 - same settings, different exposure

My XF1 froze on me not long ago - turned on but black, blank screen.

I think you were right and it is sticky aperture blades -
If the mechanism is reverse than what I thought,
meaning the aperture blades open up for a shot rather than close down,
then it all makes perfect sense, and the problem is a known one.

It took it a few minutes to get unstuck and all's back to normal.

For now, I'll keep shooting...