Quote Originally Posted by sunshinenorcas View Post
I have a 650D/t4i and love that thing to death. But the 600 (t3i) and 550 (t2i) are still very solid cameras and good entry points as well. I personally wanted the higher ISO (12800 vs 6400) so I went with that model. You can change the aperature with lenses, but you are stuck with the bodies capability for ISO... .
Not entirely true with the models you are referring to. The tXi series cameras, usually have the same sensor, but with an updated processor (Digic 3,4,5 (latest)). The ISO capabilities are technically the same, but the body allows you to increase it a stop in camera. If you were to take a t3i and shoot at ISO 1600 F4 exp 1/250 underexposed by 1 stop . .. and then take the the t5i and shoot at ISO 3200 F4 exp 1/250 (proper exposure) on the exact same image. Then go into post production (lightroom, photoshop, whatever else) and use the "exposure" tool to increase by 1 stop of light. Then ZOOM into the pixels in the shadows, or highlites, and compare the noise of the two cameras, it will be the exact same, and the image will look nearly identical. So even though your t5i can shoot 3200 or 6400 natively, you can still shoot at 1600 and increase 1 or 2 stops to get to 3200 or 6400 in post, and the noise levels produced will / should be identical based on the sensors technology.

Confusing eh?