Great attention has been paid to the engineering and design of this adapter, and it's probably fair to say the Fujifilm designers consider the effort put in equivalent to that of designing a lens from scratch. One press of the function button on the side of the adapter brings up the Mount Adapter Setting mode on the camera. From there you can specify the parameters of the newly-attached lens. If your desire is to increase your photographic vocabulary, and you are an X-Pro1 owner (or if you want to be), this decision is a no-brainer. Your time machine is here.