As you can see from the video comparison above, the lenses react completely differently between the 5D and 7D.

Here are some specs on what you get with certain lenses.  The first column represents the standard Canon 5D Mark II lens and the second column represents the conversion when you put the same lens on the Canon 7D and get the 1.6x crop factor.

On a 5D       On a 7D
8mm = 12.8mm
10mm = 16mm
14mm = 22.4mm
17mm = 27.2mm
20mm =  32mm
28mm = 44.8mm
35mm = 56mm
50mm = 80mm
85mm = 136mm
105mm = 168mm
135mm = 216mm
200mm = 320mm
400mm = 640mm
500mm = 800mm
600mm = 960mm

Happy Shooting!
Joey Mathews
31Films