Just to expand a little more on question #1: The only function you lose when you use "other lenses" is the ability to autofocus. Your sensor will still "see" through the lens and give you all the information for focusing, exposure, etc. You will want to gets lenses that have aperture control on them, otherwise you will not be able to change aperatures once it's on your Fuji camera. I have new Rokinons and old Olympus and Helios lenses that I use with cheap adapters and I think I have more fun with them than with the more expensive Fuji lenses even though I have to manually focus. Hope this helps and have fun!