This is a very simple concept, but often misunderstood.
The 1.6 crop sensor in most Canon bodies is physically smaller than a "standard" 35mm format full frame sensor. The lens will cast the same size image circle, however the 35mm format will capture more of the image whereas the 1.6 sensor will capture a fraction of what the 35mm captures. This gives the impression that your magnifying the view, but you're not. You're just seeing less of it.
Here's an illustration that might help you to understand what's happening.