This was a fascinating little creature, perhaps 4" or so in size. The rest of the group had moved on, leaving me alone to shoot, and the electric lights were extremely dim where this bat was hanging. I had to frame/shoot in almost complete darkness. I had quickly switched from the Canon 17-35 mm lens to the Canon 28-135 mm lens to shoot this image. It was taken at 135 mm, with ISO 100, f/9.0 and 1/200 second. The 550EX flash, which has its own AutoFocus Assist Light, was able to get a pretty crisp focus, and I used this light to try and see where to point my camera.