i just bought a sony DSC-F828 camera with a 7X optical zoom. I've been looking at other lenses online just out of curiosity and have a question. I see a lense that is a 2X lense for my camera. It says 2 times conversion factor of existing lense. Does this mean if i put this lense on my camera it will multiply my existing 7X zoom by 2, making it a 14X? Or does it just mean it is only a total of 2X optical zoom lense and isn't as good as my existing lense?