Canon 7D, Sigma 150, f5.6, 1/200, ISO 200, tripod, fill flash.
Original image is here http://dbolt.smugmug.com/Photography...81254061_vS7bn
PP: Cropped to square, Polar Coordinates filter, a 90 CW rotation, some cloning to even out the black, sharpened flower, Soft Light blend (~50%).
I was pleased with how this one came out. I'm looking through my flower pics for more images with dark backgrounds.