i have a sony f717 digital camera which has a 58mm thread. i have a super fisheye lens that screws on the front.

i have a pentax k1000 film SLR with a sigma zoom lens, it has a 67mm filter thread.


can i use my 58mm fisheye on the end of the sigma lens?

on ebay there are 58mm to 67mm "step-up" rings.


my question is, do these adapter rings work both ways? do i need one that is specifically designed to take a 67mm thread lens and screw on a 58mm filter?

hope that question makes sense... (ie will any "58mm to 67mm step-up ring" work?)

cheers,

it looks as thought they are threaded, male and female... and so i specifically need a 67mm -> 58mm