Today, we were attacked by a heavy thunderstorm. I guess there was a huge cumulonimbus right above us that was similar to the one I shot. It was way after the sunset, and it was dark. This image was shot at f3.2 and at ISO100. The shutter was set to 13 sec., but it is too short to yield properly visible image, but the lightning helped.
So, this is the "genuine" flash photography! Due to its heavy rain, the window was closed, and the window glass was right in front of the lens. Excuse me for some reflection of form the interior of the room. Please don't ask about the power of the flash.