Thank to those of you who gave good information! I stated that I have a rebel t3i, but that's not a professional camera. I also stated that I think I'd like another Canon. I guess my question should have been, if you are a professional outdoor portrait photographer with a business, what kind of camera do you use? Regardless of budget and if I can afford it right now or not, I'd like to know what exactly kinds of cameras professionals use. By kind, I mean brand, type, model, lens, etc. I feel that's a valid question and thank you for those replies that were serious.
Professionals use whatever they think produces best results. What exactly that would be ... is of course an issue of debate.
If you actually look at gear professionals use in the field, be prepared to be surprised. You might find really old cameras and/or lenses.
And actual professionals you (rarely) meet on the net test their equipment themselves because they dont trust online tests. They buy the same lens multiple times (to get a good copy) and they return a lot of stuff that gets good reviews.
Nobody can test everything, though.
But especially it is NOT true that the most expensive equipment would be the best equipment. That *can* happen, that *does* happen, but it doesnt necessarily happen. *Many* people are motivated to tell you that, though. See for example Ken Rockwells (1) disclaimer on most of his pages that you should buy through the links he provides. Now Ken Rockwell is a nice guy and tells you he gets money this way. And he doesnt reliably tell you all the time to buy the most expensive stuff. But thats what happening with many other online reviews, too. Thats why everybody tells you the most expensive stuff is best, because their profit depends upon how expensive the stuff is you're buying.
It is also NOT true that sharpness is the only thing thats relevant about lenses.
Microcontrast for example is a huge issue as well (2) and no online test ever tests for that. Because, well, in order to make a lens expensive, you have to put a lot of glas into it. And guess what, the more glas in a lens, while sharpness, chromatic aberations etc improve, other qualities get lower - colors, microcontrast, etc.
There was even a funny article from Rockwell once in which he complained that film gets better colors - making the same picture taken looking a lot more bland. But he used an "old", simple lens for the film examples, while he used "modern" lenses for the digital ones, so I'm not really sure this test actually proves that film would be better than digital with colors.
Same goes with cameras and Megapixels. The more Megapixels, the smaller is the individual pixel. Thats why old low Pixel count cameras like the Canon 5D and Nikon D700 are still very popular among people - they love the colors they get from these cameras.
(1) Yes Ken Rockwell is a questionable source, but he has many qualities that other sites are missing, like high resolution example images and he is one of the few sources on old lenses, and the shortcomings of his reviews are due to his own character, not because he gets paid by anyone.
(2) But please dont think that Zeiss is the only company that has lenses with good microcontrast, or that all Zeiss lenses have good microcontrast.