I was improvising, actually ^.^ The 60mm really isn't wide enough to pull this off (bear in mind the 7D is crop-sensor, so you get an extra 1.6x "zoom" compared to 35mm film, solely because the 7D sensor is smaller than a film frame).

My 17-40L let me down a little because it just doesn't let enough light in (it's an f4) - all I got were exposure warnings and blurred shots. The 60mm Macro (an f2.8) was all I had with me at the con, so I bolted it onto the camera and went with it. I may have annoyed the DJs a touch by stepping behind the gaffer-taped lines marking the dancefloor and designated walkway ^.^;