First off, I hope the next versions of the cameras and converters will have some sort of contact that tells the camera you’re putting either the wide or this-tele converter on. I found it quite a hassle to have to use the menu to tell it when it is on or off. In my case, the converter was constantly on and off, so while I used it, I changed my function button to set it to the correct converter. The converter does not seem to lose any quality or light when used. Much like the wide angle, it performs great and the results are absolutely nothing to complain about. I did find that the AF performance dropped slightly when used, but it was still workable in most cases. When attached to the camera, the EXIF data sees it as a 33mm  (±50mm equivlent ). The converter does add a bit of weight and size to the X100s, as you can see in the photo above…….

Source: www.neillsoden.co.za