Spiderman Trilogy UK Box Set question?

[kashif]

I got the Box set having all 3 movies from Amazon UK. But when I tried all the discs, I find that the first disc has different aspect ratio then Spiderman 2 and 3. The first part plays on full screen on my HD TV but the other two are in scope format. Why is that?

Also this happens with some of my other discsc two like Sweeney Todd, Bonnie and Clyde etc. Why they play on full screen always while others dont? dosent playing on a full screen affects viewing quality?

Like for example in the dark night only Imax scenes are in full screen and not the whole movie. Ofcourse they can made rest of the movie to be full screen as well but they didnt and I was thinking that maybe making it full screen makes picture quality difference!