Canon s5-is adapter and lenses+question

Hello all, I am new here :).

I have a Canon s5 and I wanted to know how can I attach lenses and filters.
If you could name all the parts I would need, it would be great.
Should I buy a 58mm or a 52mm?

And the other question is..
When I picture a very far landscape on 12X zoom and put the focus on infinity, the picture comes out not very sharp.. My friend told me that it is because its a DSLR..
I dont know if he is right, but I hope so.. So I'd know nothing got screwd up.

Thanks alot,
Maor Grab.

i need same answer if anyone can help me

Try this thread. - TF

http://forums.photographyreview.com/...ad.php?t=64784