I'm not sure what this does...

It came with the bigger zoom. I think it has to do with lighting or shading, or something like that. I did just look in my owner's manual and I can't find anything on it. I really need to watch the DVD's that came with my camera...
So I tried it out. This first picture I didn't have it on.
When I went to put the thing on my lens I realized it would only fit the bigger lens and I had used the smaller lens. That is is why the zoom is greater on this second picture. That and I didn't stand in the same place because I had to dig out the second lens. I don't know if I can tell a difference, I'll have to keep playing with it.