Well, the punch line is ... a thoroughly covered surprise event. Actually, I'm not quite sure about the term "flash mob" as it was announced to some people prior to the performance and by the Drag bicycle vendors 10 minutes prior. The fact that the location for the flash mob was also the backup location for a speech for the Princess of Belgium was simply an added bonus. In any case, it was a unique aligning of the stars when these two events collided and I'm glad that we were there to see it. I think the Princess was too.
The "flash mob" was announced to us through a colleague at work. It was to take place in the underground of a metro station at 11am on Sunday. We arrived about ten minutes early and I took advantage of the time to set up a few Pocket Wizards.
I set one flash on top of the TT1 that I was using on my camera and pointed it at the white ceiling of the subway station. I asked Elise to hold the other one and point it at the ceiling beside the flash mob. All shots were taken at f5.6 with the 17-40mm lens and the flashes set to ETTL. The on-board flash was set to underexpose by 2/3 of a stop. I continued to use the back focus button to track the dancers and just shot away, trying to wait for a moment that the dancers were in a unique pose. The camera was initially set to Av mode at f4.0 but I quickly realize that the shutter speed was far too long. I then moved the aperture to f5.6 and 1/200th of a second in manual mode. The produced the results that you see above.
Now, I hear that there might be more performances like this one so I'm looking forward to getting the inside scoop on the next surprise performance.