this is what I wrote in my PM to rklepper:
Hi. I saw your post about 8x add-on lenses for your S50.
I presently have an S45 and I use a CKC lens adapter with a CKC Sharpshooter 8x teleconverter. This lens is very good, but at an extra 8x zoom on my S45, I just can't hold it steady enough to take pics without some blur unless I use a tripod. When used with a tripod, it takes very respectable, sharp images. I took some nice pics of the full moon earlier this week and I was pretty impressed, but most of the time when I'm out with my camera I don't want to lug around a tripod, so I have decided to sell the lens as my shaky hands just can't hold the camera steady enough when I'm "out in the field" without a tripod.
I have the lens listed for sale in the Marketplace forum if you're interested. The CKC adapter is not for sale though as I still use it for macro lenses and filters.
Hope this helps you out.