i have been looking at telephoto lenses for my fuji s5600 camera, you can get them on ebay cheaply but the highest one is 2X, will this add 2X or double your camera zoom? e.g. my camera is 10X optical zoom, will the lens make it 12X OR 20x ???

My wife has the same camera, and has a doubler lens like that...it takes the camera out to 20X optical zoom (doubles the original focal length), and if you get one that's a name-brand with decent optics (i.e., not a cheapie knock-off with a blob of plastic for a lens) you'll like what it does for you. My wife does a lot of wildlife photos with hers (birds and animals, that is...not what the neighbors are doing at their party) and has done some prize-quality pics with it. By the way - don't drop that camera...we found out the hard way that the zoom element in the lens can come loose if it's jarred...has to go back to Fuji for repair!!

i have the finepix s5500 a great camara

it takes the camera out to 20X optical zoom .

take a look at this one

http://cgi.ebay.co.uk/3-2x-HD-Telephoto-Lens-for-Fuji-S5200-S5100-S5500_W0QQitemZ190067263753QQihZ009QQcategoryZ30070QQrdZ1QQcmdZViewItem

The only downside of the lens multipliers is that they aren't as good (relative to a lens designed for that magnification) for low light situations. The only other problem is that if used with an already powerful zoom lens then shake can become a problem. Putting the camera on a tripod can help but you've still most of the weight in front of the tripod pivot. If you look at mahusive zoom lenses they tend to have tripod attachments on the lenses themselves rather than on the camera...
But for everyday use (ie good light conditions) and assuming you get a good one (as previously mentioned) they're a cheap way of getting better images...

By the way, my wife's doubler is an Olympus. She's still very happy with it, after 6 months' use...seems to be good quality (of course, it's made by a known camera company, and the optics are as good as the camera's).

thanks for the help guys