For the money, Canon delivers an excellent noise profile in the T2i. Photos taken with it look clean up to and including ISO 800; at ISO 1,600 they begin to lose a bit of detail. Its usability beyond that ISO depends upon scene content and lighting.
A with most of its competitors, the highest ISO sensitivities can be useful for images that will be reproduced at small sizes; however, but there's too much color noise for decent prints. (1/80 sec, f4, evaluative metering, AWB, 18-55mm lens at 18mm, Faithful Picture Style)
As always, Canon excels with its noise-reduction algorithms; however,it seems to start off with a surprisingly low-noise image to begin with, at least at ISO 3,200.(1/30, f3.5, evaluative metering, AWB, ISO 3200, 18-55mm lens at 18mm, Faithful Picture Style)
By the numbers, the Pentax K-x displays lower noise at almost all ISO sensitivities than the Canon T2i, with the greatest disparities at ISO 6,400 and ISO 12,800. Clearly, Pentax (bottom) preserves sharpness better and Canon (top) has a lot more color noise, but I'm not crazy about some of the Pentax's artifacts , as you see on the money. (Canon T2i scaled down to match the resolution of the K-x. The Pentax's poor default color settings are responsible for the color differences.)
As mentioned on the previous slide, by the numbers the Pentax K-x performs better at all ISO sensitivities. However, in scenes like this we prefer the smoother albeit softer and more dithered appearance of the Canon (top) to the blockiness of the Pentax (bottom). (Note: these were shot at different times.)
Canon's inexpensive 18-55mm kit lens delivers reasonably sharp images. Keep in mind that other manufacturers tend to dial up the sharpness a bit more than Canon for their defaults as well.
(1/40 sec, 1/4.5, ISO 200, spot meter, AWB, Standard Picture Style, 18-55mm lens at 33mm)
Unlike Pentax and Sony's competing models, Canon takes a light touch with its default color settings. In fact, Canon has more defaults that deliver accurate color than any other manufacturer. While its Standard Picture Style does boost contrast a touch, it doesn't cause wholesale hue shifts the way others do, or as its Landscape setting does.
Though it's not the fastest burst shooter in its class--and we keep wishing it were a touch faster--the T2i's speed and autofocus tracking are certainly up to common action shooting. This shot would have been a bit sharper if our panning skills weren't rusty and I'd used a slightly faster shutter speed. (1/160 sec, f5.6, evaluative metering, AWB, AI Servo AF, Faithful Picture Style)