Canon EOS Rebel T2i Performance, Timings, and Image Quality

PERFORMANCE
Any time you evaluate a DSLR, even at the entry level, you expect an increase in overall performance compared to even strong compact digitals, and the T2i does not disappoint. Overall shooting performance was generally in line with its class competition.

Shooting Performance
The T2i powers up quickly and is essentially ready to acquire focus the instant you flip the power switch. Sensor cleaning has been relegated to shutdown instead of startup as the default, which makes more sense. Studio timings produced 0.02 second shutter lag times, and 0.18 seconds for AF acquisition. Shooting in the field, I felt using only the single center point for AF was slightly quicker than allowing the camera to use a number of points in auto AF. The center point is the only cross-type in the nine-point AF system, which may account for the perceived speed advantage.

Shutter Lag (press-to-capture, pre-focused)

AF Acquisition (press-to-capture, no pre-focus)

Continuous Shooting

*Note: Continuous shooting framerates are based on the camera's fastest full-resolution JPEG continuous shooting mode, using the fastest media type available (300x CF, SDHC, etc.). "Frames" notes the number of captures recorded per burst before the camera stops/slows to clear the buffer.

Single shot-to-shot times are as quick as you can shoot; react to the shutter by going back to a half push for AF acquisition and shoot again, which was about 0.75 seconds in my case. Continuous shooting rates came out to 3.7 fps, as advertised.

Canon lists the T2i flash guide number as 43 feet at 100 ISO. This is a wide angle range of about 12.28 feet and 7.67 feet at telephoto. Recycle time is listed as about 3 seconds. Both range and recycle times listed were accurate based on flash test shots with a fully charged battery.

The battery will get you about 440 shots using the viewfinder in 73 degree F temperatures, or about 400 shots at 32 degrees based on CIPA standards. The number of shots drops to 180 and 150, respectively, if you use the monitor for live view shooting. Compared to its competitors, the T2i is about 60 shots short of most brands, and 1,500 behind the overwhelming class leader.

Lens Performance
The 18-55mm f/3.5-5.6 stabilized kit lens is about average in speed compared to similar lenses from competitors. Canon rates the stabilization system for up to four stops of camera shake reduction. Construction comprises "11 elements in nine groups and uses an aspherical lens element to correct aberration... ." I noticed some image softness in the corners but otherwise fairly consistent sharpness across the frame. There is barrel distortion present, but chromic aberration (purple fringing) was well controlled.

Telephoto displayed more dramatic softness in the corners at f/5.6, but it improved as aperture was closed down to f/16; still a bit soft, but definitely sharper than wide open. At 55mm, I would try to shoot the lens at f/11 - f/16 if possible, assuming depth of field and shutter speed issues are not factors. There were some slight increases in purple fringing in comparison to wide angle, but primarily it took enlargements in the 200% to 300% range to make the faults apparent.

As mentioned earlier, the T2i has a PIC setting that is enabled as a default, and lightens the corners of images darkened by falloff due to lens characteristics. The camera contains data for about 25 lenses and applies correction based on the particular lens that is mounted. Here are shots with PIC disabled and enabled; the difference is slight but noticeable, and histograms for each shot show nearly identical curves but with the enabled shot shifted toward the light end of the scale.

The lens can focus as close as 9.8 inches (from the subject to the focal plane of the camera sensor), which means the front of the lens can come in to about 4.75 inches from the subject no matter what focal length is selected. This offers a fairly good close-up capability without resorting to the macro scene mode, which doesn't affect the focus distances involved anyway. You can go from shooting a fire hydrant across the street with the lens set at 55mm, then shoot a macro of a rosebud without changing settings.

Video Quality
Video quality with the T2i is good. Basic sound is recorded as mono, but stereo is possible by connecting an external microphone equipped with a stereo mini plug to the camera. Because the camera uses a CMOS sensor, the "rolling shutter effect" that causes vertical objects to appear bent as the camera is pans past them must be considered. There is rolling shutter effect present when the camera is panned at exaggeratedly high speeds; pans at more normal rates exhibit slight distortion and are not distracting unless you're looking specifically for the effect.

Canon recommends a class 6 or faster memory card for movie capture. A full battery provides about 100 minutes of recording time at 73 degrees, and 80 minutes at 32 degrees. Battery life notwithstanding, movie clips are limited to 4GB size or 29 minutes and 59 seconds duration. A new clip will need to be started from either point. Shutter speed, aperture and ISO sensitivity can be set manually for movie shooting. Zooming lenses with apertures that change during the zoom (the T2i kit lens, for example) is not recommended as exposure may be impacted. When shooting at 640 x 480 resolution, there is a "crop" option that applies a 7x magnification, producing a much more dramatic telephoto effect to whatever focal length you use.

Autofocus is possible during movie capture, but continuous AF is not. After the initial AF is established, if you autofocus during movie shooting "you might momentarily throw the focus way off or change the exposure".

Image Quality
With the T2i's 1.6x crop factor and the 18-55mm zoom, our available focal lengths run from about 29 to 88mm in 35mm equivalents. That range encompasses the narrower end of the wide angle category, and extends to the starting point for telephoto. However, the T2i's 18 megapixel resolution offers some room to crop and a little more apparent magnification. Here is an original sunset shot and the same shot cropped to 18 x 12 inches at a 200 dot per inch (dpi) resolution that will be a good quality photo print. If you look carefully, the cropped shot gives us a "closer" look at Santa Catalina Island with the sun dropping into the ocean off its west end and the island is about 57 miles away. It's the same situation with the hyacinth macaw - the 55mm doesn't very close, but cropping does (18 x 12 inches at 212 dpi).

Original	Cropped
Original	Cropped

Default images from the T2i were generally pleasing and accurate as to color reproduction. I ultimately added a couple steps of sharpening to the "standard" picture style, but many viewers would likely be happy with the default setting.

The camera has an "auto lighting optimizer" (ALO) feature that is designed to increase brightness and contrast in images that appear dark. The function is automatic and in-camera with JPEG images, and a post-processing option with RAW files. ALO is enabled at its "standard" level as a default, but there are "low" and "high" settings and of course, "off". I shot my usual high contrast mission fountain images in aperture priority with ALO enabled at the high setting and again with the feature disabled.

Differences between the two shots were subtle, but histograms showed that with ALO enabled at the high level, both dark and light ends of the histogram were shifted slightly toward the center of the range. In other words, darker areas were lightened and light areas darkened. There was little difference between the histograms for the no and low ALO shots.

Evaluative metering is the default setting in the T2i and the method I used for virtually all shots in this review. Here's a more detailed explanation from Canon's website:

The EOS Rebel T2i features Canon's newest dual-layer sensor, with 63 zones. By measuring not only the amount of light, but also taking into account color and luminosity, this new system delivers a very high level of accuracy for better results every time. Since the metering sensor has a color measurement function, exposure errors and focus errors caused by different light sources are minimized; the EOS Rebel T2i gives stable exposure from shot to shot in situations where light changes, such as sports on a cloudy day, or indoor holiday scenes.

I found the T2i did well on average lit scenes, but it would tend to lose highlights in high contrast situations that challenging for most cameras. The camera has a "highlight tone priority" (HTP) custom setting that is disabled as a default. Enabling same "improves the highlight detail" and "the gradation between the grays and highlights becomes smoother." Histograms of shots with and without HTP were quite similar, but showed the enabled shot histograms were shifted slightly toward the light end of the range. The downside to enabling the setting is the loss of 100 ISO sensitivity and "noise may become slightly more pronounced than usual." There are also partial, center-weighted and spot metering options available.

Canon's "picture style" palette offers standard, portrait, landscape, neutral, faithful and monochrome color options. Here's what those look like:

Standard	Portrait
Landscape	Neutral
Faithful	Monochrome

The T2i file output is at 72dpi, which results in images 72 x 48 inches in size. You have to downsize to send in an email (unless your friends really like scrolling) or change resolution to print at photo quality.

I used auto white balance for most of the shots used in my review, and found it to be generally accurate, but the T2i shot very warm under incandescent light in the studio. Daylight, shade, cloudy, tungsten, white fluorescent, flash and custom settings are available as well.

Auto White Balance, 3200k incandescent light

ISO noise performance was predictably good; the large size of DSLR sensors compared to compact digitals is the first line of defense against noisy images as sensitivities - and resolution - increase. ISO 100 and 200 are clean and hard to tell apart. There is a hint of some noise creeping in at 400, but only if you examine the frame enlarged; small images will be almost impossible to tell apart from 100 or 200.

ISO 100	ISO 100, 100% crop
ISO 200	ISO 200, 100% crop
ISO 400	ISO 400, 100% crop
ISO 800	ISO 800, 100% crop
ISO 1600	ISO 1600, 100% crop
ISO 3200	ISO 3200, 100% crop
ISO 6400	ISO 6400, 100% crop

ISO 800 has a very slight increase over 400 and would be hard to tell apart from the lowest sensitivities in small images. ISO 1600 shows a bit more noise and there's a drop in quality during the jump to 3200, but still very usable, particularly in small images. ISO 6400 takes another noticeable dive but still is a go-to ISO when needed, and particularly if image size is small. We didn't shoot the expanded ISO (12800) in the studio, but here are shots with and without flash at 200 and 12,800 to get an idea of what to expect. Even 12,800 looks viable in a pinch for small images.

ISO 200	ISO 12800
ISO 200	ISO 12800

Additional Sample Images