Wed Apr 30, 2014 10:22 pm
As the others have written, the Nikon mount multiplies the useable camera mounts but you'll be stuck with adapters if you're a Canon photog. Decent adopters tend to be expensive and they all loosen eventually. If you're cycling your primes off and on your cameras often enough, you might need a set of five. Staying with EF removes that problem at least, plus the wrong-way focusing, which will be an issue with stills at least. EF will work with E and X mount cameras, as well as MTF, which are all looking better all the time.
I'm sorry to hear the 4k is finicky in the ap control department. That lack of an external ring is a scary aspect of the EF version -- you really are stuck with Canon and Canon-active mounts and adopters, as a practical matter. Month by month this feels a less appetizing place to be. The endless delay with the EF-MTF Speedbooster is just the latest example of this, against a backdrop of the high cost of Canon's "cinema" cams.
It's a big investment you've undertaken but things are changing so fast these days that "future proofing" is probably just an illusion and planning for what you're actually doing or about to do is probably best. Once you're using the gear, features that save time loom larger in importance -- features like aperture control maybe.
Good luck