This ultra wide angle lens is a marvel of engineering and Canon has succeeded. The images are clear and bright. Buy it and you will have a lot of fun re-shooting old favorite places. Just think of the three words that will guide you when using a lens like this: low, close and geometric. That means you're often on your knees, getting closer to the foreground than you ever expected, and looking for images with lots of long, grid-like lines. It's great for slot canyons and narrow city streets, tall buildings with fountains or sculptures in front of them. It works great on my new Canon EOS 5D Mk3. Panoramas are literally instantaneous.