The camera upgrades the Rebel XT's 8.2-megapixel sensor with a 10.1-megapixel model, and the 1.8-inch LCD (liquid crystal display) with a 2.5-inch screen, Canon said. Its autofocus system calculates focus with nine points of image data, rather than the previous seven.
The camera costs $899, including an 18mm-to-55mm lens. The camera, which will be available in stores in mid-September, is known as the 400D in some regions of the world.
Tackling a problem common to digital SLR (single-lens reflex) cameras, the Rebel XTi comes with an ultrasonic image-sensor-cleaning system, the first in a Canon SLR. Dust on the sensor can leave dark spots in the image.
Olympus was the first SLR manufacturer to add automatic sensor-cleaning technology. and Panasonic's DMC-L1, both introduced in June, also include autocleaning technology.
In the SLR market, Canon competes chiefly with No. 2 Nikon, which sells its entry-level D50 and the new D80.
The Rebel XTi maintains the, called APS-C, and trims images down by a factor of 1.6 compared with 35mm film SLRs. The camera can still shoot at a maximum speed of three frames per second, but in burst mode, it can now maintain that rate for as many as 27 JPEG or 10 RAW images.
Increasing the pixel count for an image sensor of a given size means each pixel is smaller, a fact that can lead to higher noise in the image and lower sensitivity to subtle gradations of light. Canon said its new sensor, however, has the same per-pixel quality as its 8.2-megapixel predecessor.
The low noise is possible because Canon didn't shrink the tiny microlenses, located in front of each pixel, that gather light and direct it toward each element of the sensor, but rather packed the microlenses more tightly, the company said. In addition, it increased the sensitivity of each photodiode sensor element.
Canon also announced two new high-end "L"-series lenses that will go on sale in November. First is a $1,599 50mm lens whose f/1.2 aperture is well suited to low-light conditions.
Second is a 70mm-200mm zoom lens with an f/4 aperture. Canon already sells a similar model, but the new option adds image stabilization to compensate for shaky hands or lower light conditions. Canon estimates its cost will be $1,249.