liamnas

You can use and adapt Fujinon PL mount Super 35 cine lenses.
 
4K video has an additional crop factor of 1.17, so all Super 35 lenses will work perfectly. There are adapters for PL mount on X-mount, for example: http://www.ebay.com/itm/Arri-PL-mount-lens-to-Fuji-X-Fujifilm-X-Pro2-x-mount-camera-ciecio7-adapter-/261118309301
 
While Fujinon offers a good choice of professional PL cine lenses, there are also great PL mount options from several other brands like Cooke, Leica, Angenieux, Zeiss, Panavision etc., not to mention more affordable "to own" (as opposed to "to rent") options from other manufacturers.

Everything needs learning, cameras don’t take pictures on their own, especially professional cameras don’t! Maybe I don’t find this difficult because I’ve been doing this for 35 years. On a 35mm I used routinely a 15mm so a 14m (or the 10-24 I’ve used and the 12 mm that I do use now) doesn’t make me think it is any difficult to use.
 
This is a 10mm
 

Maybe eventually, but I think Fuji is really focused on building out the system for photography right now.
 
Some of the wide angle primes Fuji has out right now would be damn good for video I think.

in the uk you can get replacement caps direct from Fuji, i imagine in other parts of the world it is similar
 
http://shop.fujifilm.co.uk/accessories/caps-straps
 
Personally I have never lost one, when putting the lens away (the 35 f/1.4 or 18 f/2) I put lens cap on then attach hood, and hood cap which stop it coming off in the bag.
When the camera is in use, the caps are kept in the bag (lens hood is always on the lens)
 
welcome to the forum

Lens caps from China they are so cheap so worth to buy several different and pick one that fits in the best way, then you'll have one + spares.

eBay - http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l2632.R2.TR3.TRC2.A0.H0.Xlens+cap+43.TRS0&_nkw=43mm+lens+cap&_sacat=78997

There are several styles in stock at B&H in the 43mm size - pinch-to-remove - even a nice metal screw in type if you want to be super-retro. One of the best looking models says "Canon" on it in big letters. (I have no idea what that means.)
 
If you use the little hood that comes with the 35/2, you may be able to find a push-on type (obviously a little bigger than 43mm) that that would allow you to keep the hood mounted and the lens covered.