A few of my friends has asked me similar questions: "Should I buy Canon T2i or Canon 7D?", "What is the difference between Canon 7D and Canon T2i?", "Canon 7D and Canon T2i has the same sensors, why is 7D double the price?"
First of all, when money is not a key factor on making the decision, I would highly recommend you go for the Canon 7D. And I am going to list most of the advantages of Canon 7D for you.
First and most evident is the build. When you hold the two DSLRs, you will discover a difference in the construction. The Canon 7D has a magnesium body with weather resistant seals, while the T2i is made with some metal parts, but not nearly as well constructed as 7D.
Second is the control features. As a digital photographer, you will notice there are more control buttons on the 7D and they are considerably more advanced. The switch dial and the Top LCD control panel which are missing from the T2i are able to help you get the job done easier. (Believe me, when you are more into photography, you will demand functions both on your camera). It is just a lot more specialized than the lower end digital SLR.
Third is the Video function. The Dual Axis Electronic Level shows both pitch and roll angles on your viewfinder and LCD. A dedicated switch can change from other shooting modes to movie mode makes it easier for operation plus full manual control over shutter speed and aperture.
Forth is the burst rate. Burst rate is the amount of pictures that can be taken in one second. It's 8.0 frames per second vs. 3.7 frames per second. It’s a definite advantage for the more advanced elder sibling.
Besides the four major advantages of Canon 7D, following is a few more:
- New 19-point AF system (awesome, better than all other current models)
- 1.0x magnification and 100% coverage viewfinder
- Wireless flash control
- Dual DIGIC 4
- 3 Custom Modes on the dial
- higher-rated shutter life
- Lens micro adjustment
- 1/8000s shutter while T2i has 1/4000s only
- ... and more
As I mention at first, if money is not the important factor for your decision. Canon 7D is the way to go. If you are tight on budget and are looking for light weight smaller camera body, Canon T2i is also a good choice since it can produce similar result as Canon 7D
Regardless of which one you choose, you can get Canon 7D for $1562 Shipped or Canon T2i for $799.99 Shipped here.