Anyone familiar with earlier Digital Rebel models will feel at home with the new Canon Digital Rebel T2i. The control layout and operation of the T1i and T21 are quite similar.
The Digital Rebel T2i, like the T1i has a "CA" or Creative Auto mode. The "CA" mode defaults to the same as full auto mode, but you can program it for things like white balance, ISO etc. What you can't do is change it from full automatic exposure (i.e. you can't select Av, Tv etc.). It's really an "advanced beginner" mode. The shooting modes available are (moving clockwise around the dial): A-DEP (Auto depth of field), Manual, Aperture Priority, Shutter Priority, Program AE, CA (creative Auto), Auto, Flash off, Portrait, Landscape, Close-up, Sports, Night Portrait and Video.
The rear controls of the Digital Rebel T2i are mostly similar to those of the T1i. The "direct print" button now has an alternate function which brings up a Quick setting mode on the LCD which allows rapid access to the main shooting parameters such as metering mode, AF mode, drive mode, ISO setting, exposure compensation, white balance and exposure settings. There is now a dedicated button on the T2i (located immediately to the right of the viewfinder) which controls Live Mode on/off, or, when the command dial is set to video, it starts and stops video recording.
The menu functions and layout are similar to those of the Rebel T1i and are displayed on the new high resolution 1,040,000 dot 3" LCD, which now has a 3:2 aspect ratio. The LCD cover has Canon's new coating which lowers reflections, increases visibility and provides more scratch protection. I'm not going to go through every menu item since that would be pretty dull reading. You can download the Digital Rebel T2i manual from the Canon website as a .PDF file.
Operational speed of the Canon Digital Rebel T2i is fast. It appears to be "instant on", though in reality it probably takes about 1/10s to wake up. Image recording and playback are both fast, despite the larger size of the 18MP image files.
In actual tests using a class 6 Kingston 8GB SDHC card, with the camera set to ISO 100, manual focus and manual exposure with a shutter speed of 1/400s, I measured a continuous shooting rate of 3.56 fps when capturing Large/Fine JPEGs and the buffer held 45 images before the frame rate dropped to 2.5fps. In RAW mode I measured 3.53 fps for 7 frames (the T1i buffer held 10 frames). Then the buffer filled and the frame rate became irregular. After 3.5 seconds two rapid frames were shot followed by 2.2 second gap, then a 4.5 second gap, then a chain of frames about 2 seconds apart. A faster cards such as the 30 MB/s class 10 SanDisk Extreme series might well provide an improvement in buffer size but I didnít have one on hand for testing. Note that in common with other EOS DSLRs, the use of high ISO noise reduction results in a reduction in the number of images that can be stored in the buffer, presumably due to the fact that the image processing power required for noise reduction slows down writing from the buffer to the memory card and so the buffer memory fills up faster.
The Digital Rebel T2i viewfinder is very similar to that of the T1i, with the same coverage (95% linear), the same magnification (0.87x with 50mm lens) and the same information display. ISO is displayed all the time along with the usual shooting parameters and flash information.
The Digital Rebel T2i uses same pentamirror system as other cameras in the Digital Rebel lineup and the viewfinder screen is smaller than that used in the 40D/50D/7D, 5D and 1D series cameras. Though it's smaller I find that I really don't notice the difference between the T2i and the 40D unless I'm using both cameras and switching between them. If you're just using the T2i you soon get used to the smaller viewfinder.