OP I think you need to go out and buy a book or find a dvd that covers all of this. This is the first time ive ever seen someone so caught up in trying to learn everything about photography before having a camera to practice on. You want to know how the framing works just look through the viewfinder. If it isnt wide enough then buy a wider angle lens. And now you want to know everything about depth of field. Is this really going to make a difference in what camera you are going to buy? I think you have already bought and sold an entire system of cameras and lenses in your head without having actually taken a single picture.
Like some have said the ff is a better choice outside of cost. Indus has the cameras and is giving first hand knowledge and you still dont get it. Of course he hasnt compared the d7100 cause it aint even out yet so thats kinda impossible for him to do.
Now you're just coming off as elitist.
If you can't tell, I obviously want FF and if I got one, I'd have no problem understanding how things work.
That's the "sensor size" I've always known.
When you change film/sensor size formats, without wasting time and money experimenting, as you suggest I do, there are a few technical things you really need to know if you want to "get it right" on the first try. Which, if you know your fundamentals and how you want to use certain lenses, is entirely feasible.
Everything changes, though ever so subtly, when you change film/sensor size.
I'm a researcher - and considering this is going to be a few thousand dollars I am taking a major gamble with, I will most certainly research every angle, and research it yet again. I'll admit I am a bit OCD about product researching before committing to a purchase. But you should respect that, instead of taking a "you don't know what you're talking about - just get the cheapest thing and get a good book!" position.
Many books don't exactly cover the concept of "when moving from one film/sensor size to another, here is everything you should know about what will be different."
It's a fairly minor point - and more often than not (in the average history of photography), people move UP in film/sensor size, they get new lenses for an entirely different platform (I'd love a 2x3 or 4x5).
You're reading comprehension needs work. You missed the fact that I do, sort of, have "a camera to practice on." It's a film SLR. I also have two lenses, a flash unit, and own a photography book and have taken photography courses (one w/darkroom, one with color film).
The fundamentals I understand, though sometimes the terminology I get wrong because I've been "out of the game" for awhile.
But I don't have a DX body to practice with - and I don't care to experiment by making impulsive and barely thought-out purchasing decisions, when I could instead spend a great deal of time researching the ins and outs of the exact things I feel I need to know and making my decision carefully.
But considering it seems at least one photographer here can get paid with the results of a Micro Four-Thirds body, I guess I should be able to expect that as possible with a DX body.
The other question: can I get IQ results that can see me getting paid for art-type work (as opposed to contracted professional work)? As in, a great photo of something here or a unique landscape there, that gets published, wins local or whatever contests, or when posted online sees people order prints?
Which angle I want to focus on (why not both?) I haven't decided yet. If I get a DX body and I do find success, I'll definitely move up to whatever the best FF body Nikon offers at that time (or at least, a second-top model).
I'm not over-thinking or projecting too far with these. I know it may seem that way or appear that I am naive or something, but rather this is something I have worked on, off and on, for quite some time, and now I have discovered it is what I should be going full-steam ahead with, instead of trying to make a white-collar career (though in the mean-time, I have to keep trying until one or the other ends up being the successful route

).