Canon Rebel T1i Digital Camera Review$799.99
With noise reduction turned off, the noise levels were a bit on the high side, hitting just over 2% at ISO 3200, though this is brought down to 1% if you crank the noise reduction all the way up. If any level of noise reduction is used, the noise is kept below 1% up to ISO 800, which is respectable.
We look at the different levels of noise between red, green, blue and luma (gray). Usually, these are very tightly grouped together; the T1i is unusual in having lower yellow and green noise levels than other types. More on how we test noise.
The official ISO range on the Rebel T1i runs from 100 to 3200, but has an extended range that reaches up to ISO 12,800.
The T1i has nine autofocus points, arranged with eight as a rhombus, and one in the middle. The focusing generally feels fast, though it slows down a bit in low light. Even then, it generally does an admirable job of finding the right point in a timely manner. The focusing motor isn't too loud, though when if you autofocus while recording shooting video, its proximity to the microphone gives leads to a plainly audible, a very loud grinding noise in the recording.
Three focus modes are available: One Shot, AI Servo (AKA Continuous), and AI Focus, which switches between One Shot and Servo
The long exposure test looks at both color accuracy and image noise at reduced light levels. The T1i performed slightly below average in this category, only beating the Pentax K2000, which had really struggled on this test.
This test looks at color accuracy and image noise at light levels of 20 lux or below, at exposures ranging from one to 30 seconds. We also compare how these factors are influenced by long exposure noise reduction. This feature takes a second exposure after the first, but with the lens shut, then takes the noise data from the second and subtracts it from the first. In our experience, it does almost nothing. More on how we test long exposure.
The T1i struggles a little with color error in long exposure, especially towards the 10 and 15 second margin. The noise reduction doesn't have much of an effect.
The noise levels stay a hair below one percent in this test, once again a little poorer than most other cameras in our test group, but not horrible. The noise reduction system actually boosted measured image noise at most shutter speeds, and doubles the amount of time it takes to shoot a photo. The chart below shows that the T1i scored lower than most other cameras, but by a relatively small margin.
Video: Low Light Sensitivity
The Canon T1i had a surprisingly difficult time with low light sensitivity and the numbers weren't pretty—the camera required 26 lux of light to reach 50 IRE on our waveform monitor. This is more than twice the amount of light than the Nikon D5000 required (11 lux) and it is significantly worse than your average HD camcorder. Keep in mind, however, that all our video testing on the T1i was done with its kit lens, which has a maximum aperture of f/3.5. Using a faster lens with a wider aperture setting will likely produce better low light sensitivity results.