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In Germany I paid 1600 EUR for the K-1 and the very cheapest offer from a reputable dealer for the D750 is 1800 EUR, so the K-1 comes with a free lens.
And I am not counting the fact that the D750 is a low to mid level body, basically a K-50 with a larger sensor and one single improved feature: AF.
The iphone has more advantages: better connectivity and easier to carry around and considerably cheaper.
Yes you can compare whatever you want and sometimes one side wins sometimes the other.
The first poster to state "you can not compare a D750 to a..." or "it is not a mid level camera" is a Nikon fanboy / sales rep but will not admit it (and owning a Pentax camera is not the least proof you are not a Nikon fanboy).
I can be as "educated" as Rishi and state that Nikon cameras suck, because they are poor build and poor usability. They always did.