Quote Originally Posted by CRAZY_JAY
Another thing to remember is that because of the sensor in the xti you will have to multiply the mm by 1.6 to get the correct zoom for your lens. That 70-200 will actually be a 112-320mm.
It's a 1.6 crop factor, there is NO magnification...it's the exact same zoom, just a smaller portion of the image captured compared to full frame bodies. The only differance is full frame camera's capture more of the exact same image, lenses don't magically change their characteristics when attached to different sensor size bodies...