The Fujifilm X-100 series of cameras are a hit with the buying public - we've proved that over the years. They are a hit with the travelling public too - I know because I travel with one and images it produces are magic.
But it is a camera that has a fixed focal-length lens firmly attached to the front of the body. It is superbly attuned to the APS-C sensor. If I can move back or forward in front of the subject, all is well - I frame as I please.
But if I am stuck inside a cramped space and cannot move back? Well a Fujifilm WCL 100 converter lens screws onto the front of the fixed 23mm Fujinon and widens it out to 18mm. Suddenly the shots inside the museum become possible - and the quality of the resultant image is exactly as good as the 23mm.
How about the business of bringing the far away object closer? Well, you can't expect to put the Mt. Palomar telescope on the end of a fixed focal length, but you can achieve a moderate increase in focal length. Fujifilm make a teleconverter called the TCL 100 that boosts the 23mm to a 35mm. Again there is no change to the image quality and you get to use the maximum aperture just the same.
Here's a visual map of what these focal lengths do - note: this illustration is taken with the Fujifilm X 10 camera on EXR setting.
The converters are not expensive, and they do expand your visual capabilities.