Photography: Camera sensor size difference

@Tynan - Why do you want to put your Nikon lenses on the Canon? Surely all the benefits of having a top of the range DSLR will by void as most of the features won't work as you would be using a non compatible lens? Mind you I'm not sure what you are going to be using it for.

the idea is to enable manually stopping down/opening up when shooting HD video on a 5DII. you don't have control of the aperture when shooting with canon lenses. well you do but you have to lock the exposure after getting the aperture you want by pointing at something dark/bright and using exposure compensation.