A lot of beginners make the mistake of buying a high-end camera (anything over $1000). Many beginners spend hours poring over specs, camera reviews, etc, and end up dropping serious coin on a camera that becomes outdated by the time they even learn how to exploit that camera to its full potential.
A camera, like a computer, is a tool that is limited by the input of the operator. You can have the best computer in the world, but that means nothing if all you know how to do is word processing and internet browsing. And before you know it your $5000 computer is worth just $600 and new computers that cost $600 can blow your super computer out of the water. The same applies for cameras.
Camera technology is advancing at a breakneck speed. It was just a few years ago that RED was the cream of the crop when it came to digital cinema, and a $50,000 RED rig was considered "affordable" for an independent filmmaker. Today we have the likes of Blackmagic, Digital Bolex, AJA, and more that are offering similar, if not better performance and capabilities under $10k...even down to $2k. The only reason to buy a good camera is if you know you will recoup your investment very quickly. Usually cinematographers who have a regular and steady stream of work do this because they can put the cost of a new camera into their rental fee and break even within a few months.
But not everyone is an in-demand DP with a steady revenue stream, especially not a beginner. So what should you focus on?
First, be smart and invest in glass. Unlike cameras, lens technology doesn't change dramatically. Cinema lenses from the 80s (like the Cooke Varotal 18-100mm T3, which came out in 1987) are still used today on productions. Yes there are have been advances in lens speed and size, but nowhere near the pace of digital camera technology. Furthermore, good lenses retain their resale value. When you are ready to take the next step in your career, you can sell your existing lenses for a good chunk of change years down the road. The same cannot be said for cameras. Stick with a lens system that is robust and popular.
Second, don't invest in a camera or glass until you know the basics of photography and film. Being tech savvy is a small part of the equation. Knowing how the camera and lenses work does not mean that your photography or cinematography will be good.
The Canon T3i is probably your most versatile and best bet. Not only is it cheap, but there is a huge aftermarket for Canon lenses. Furthermore, as you get to know your camera better and begin to understand the technical aspects of filmmaking, it is supported by Magic Lantern so you can "hack" your camera to get more features out of it. Do not fork over cash for a 5D Mark III as it will be completely outdated by the time you even begin to understand what it is capable of. Hell, the 7D mark 2 is just around the corner and the 5D mark 4 is already slated for 2015. Will you be a master filmmaker within a year? Most likely not.
I recommend the following T3i with the 18-135mm lens:
http://www.amazon.com/Canon-Digital-18-135mm-3-5-5-6-Standard/dp/B004MN00C4/
It's not the fastest or best lens, but it is cheap enough to teach you about photography and filmmaking. Anyone who tells you to ditch the kit lens at this stage in your learning experience is clearly forgetting how they started out in photography. You learn to drive on a Honda, not on a Ferrari! Furthermore, the cheap lens and camera will afford you the chance to make mistakes. It's not the end of the world when a lens that costs a couple hundred dollars gets scratched. However, a $2000 lens is a different story!
Check out the following kit with accessories as well:
http://www.amazon.com/Canon-T3i-Digital-18-135mm-Includes/dp/B00AFKLTQ4/
After a year or two with this camera and lens you'll begin to see the various limitations for yourself. You will also discover your preferred shooting style, which will majorly influence your next level purchase for lenses and camera. Maybe you like shooting live events, maybe you like documentary-style shooting, or maybe you like specific kinds of narrative. For example I like watching documentaries, but after editing a documentary because I liked watching documentaries, I never want to be involved in documentaries ever again. It's all a learning experience, both about filmmaking, and about you.
Lastly, before you learn about filmmaking...learn about photography! Shooting still images will give you a better understanding of exposure, depth of field, focal length, framing and shot composition, etc.
