Here is a few shots using a canon t2i with a 100mm/f2.8 and polaroid extension tubes. all the shots were done in moonlighting with incand lighting in the background. most are long exposure shots shot at 1600iso.
The extension tubes are fantastic and allows you to get very close to the subject. however, with the tubes the lens no longer focuses to infinity - you are limited in working distance as the lens will fall out of focus if you are shooting too far back. However, this is very manageable.
IMG_4772 by [url=http://www.flickr.com/people/93072545@N02/]
IMG_4773 by [url=http://www.flickr.com/people/93072545@N02/]
IMG_4775 by [url=http://www.flickr.com/people/93072545@N02/]
IMG_4777 by [url=http://www.flickr.com/people/93072545@N02/]