In article <47essr$rj7@nuscc.nus.sg>, fba40151@leonis.nus.sgö says...
>Sometime back someone mentioned making a cheap fisheye by mounting it >on a body cap.
>I was thinking of doing this on my EOS ELan and was wondering if anyone
>has experience with it and if the lens gets in the way of the mirror.

I think you may be referring to a door security fisheye peepsight, which
can be mounted in a LENS cap, and then on a lens (be careful that the rear of the peepsight does not contact the lens front element) to make an inexpensive (though, alas, poor) fisheye lens. It is worth doing,
given the low price, to gain experience with a fisheye lens (some of us
love to use the durn things...).