So I have a Canon Powershot A630 and I have been wanting to get a lens for it. So I got on Ebay and found some 2x telephoto lenses for it that are reasonably priced. So now, what I would like to know is, does this mean it's just giving me 2x optical zoom? Or is it multiplying my 4x optical by a factor of 2? Or how does that work? Also, if someone could point me in the direction of a good optical telephoto lens, that'd be great.