These are my two comparison tests of the Rebel T3i at different ISO settings and f/stops.
What's nice about these tests is that I was able to use a great lens:
the 100mm f/2.8L macro (boss rented it for a shoot, and I got to play with it some.)
I love this thing!
ISO shots were done at about two feet, as were the f/stop shots.
Nothing has been resized--only cropped down for detail.
All shots done from a tripod.
F-stop shots were focused roughly on the thumbnail indent on the first bottle opener
tool (on the left).
Flickr previews below.
Dropbox -- full resolution downloads
F-stop Test - https://dl.dropboxusercontent.com …45142/F-stop%20comp-2.jpg
ISO Test - https://dl.dropboxusercontent.com …45142/ISO%20Comp%20-2.jpg
