hello! first post, just (finally) got a nice camera today, a Minolta SRT 101b. i've been wanting a camera like that since i tryied my girlfriend's (a canon something...?! sorry, still a beginner!). grabbed it in a charity shop for about 14 pounds... good pick i guess? anyway! back to the topic... i was wondering what kind of other lenses i could get for it. the one it cam with is a 50mm mc rokkor, which as far as i know is the standard lens these kind of cameras came it. seems to work fine so far but i'd be interested in trying something new, especially i'd love to get a fisheye lens. now my question is: is there a particular size of lens that will fit on my camera and some that won't? if so, how can i tell which diameter my camera is? the lens cover says 57mm but i guess it's just for the outer ring so it doesn't have anything to do with that. right? thanks in advance for any kind of help/advice! a.