Canon T2i Video Recording

High-definition video capture has rapidly become a must-have feature in this year's digital SLRs, with advanced amateurs and budget-minded professionals alike excited by the possibility of using the same camera body and lenses for both still and movie shooting. Most digital SLR video modes to date have had limitations in terms of control and output formats that have tempered this excitement somewhat, however.

The Canon Rebel T2i's includes similar video functionality to that of Canon's semi-pro EOS 7D model, with an unusually robust feature set that gives the photographer more control over their movies, as well as the ability to record audio from an external source. Both shutter and aperture are available for manual control, and the T2i also provides multiple frame rate options, including three that match the HD television timing specs. Unlike most digital SLR video modes including the EOS 7D, the Canon T2i caters to advanced amateurs by allowing continuous autofocus during video recording, albeit with AF noise clearly picked up by the T2i's internal microphone. Pros will likely want to control focus manually regardless, but amateurs will need to decide whether the convenience of AF is worth the drawbacks.

Canon Rebel T2i Video: Image Size, Frame Rate, and Encoding

The Canon T2i's all-new CMOS sensor records high definition video at a maximum resolution of 1,920 x 1,080 pixels with a 16:9 aspect ratio -- what's sometimes referred to as "Full HD", or 1080i/1080p. Both NTSC modes of 23.976 or 29.97 frames/second and PAL modes of 23.976 or 25 frames/second are available at full resolution. The full resolution can be downsampled in-camera to produce 1,280 x 720 (720p) resolution movies, with the NTSC mode using 59.94 frames/second, and the PAL mode offering 50 frames/second. Finally, a standard definition 4:3 aspect ratio mode captures 640x480 pixel (VGA) movies, again with 59.94 frames/second in NTSC or 50 frames/second in PAL. The numerous different frame rates match various broadcast television formats etc., removing the need to transcode to the intended output frame rate after capture.

Individual movie clips captured by the Canon Rebel T2i are limited to a maximum of twelve minutes in the high definition 1080p and 720p modes, or 24 minutes in the standard definition VGA mode. (Canon didn't give a reason for this, but perhaps it's a matter of power consumption and sensor heating: We noticed that the body can get rather warm after an extended period of video shooting.) The Canon T2i records its movies as MOV files using variable bitrate MPEG-4 AVC / H.264 compression, which is much more conservative of memory card space than the Motion JPEG format used by some cameras, and avoids some of the severe image quality loss suffered by AVCHD cameras when faced with significant amounts of change in image content between frames. (AVCHD uses a subset of the H.264 standard, among other things mandating a limit in recording bandwidth, which translates into a lesser ability to convey rapidly-changing detail.) The choice of H.264 comes with the requirement of greater processing power, though -- not only from the camera when recording, but also when playing back or editing videos. The more sophisticated encoding used in the H.264 standard requires quite a bit of processor power to pull it apart and put it back together again, so frame-accurate editing of H.264 requires a fast processor and capable editing program.

Here's a list showing what to expect for file sizes with the Canon Rebel T2i's video recording:

Canon T2i Video Options
H.264 Format (.MOV file container)
Resolution	Encoding	Frame Rate	Clip Length	File Size
1,920 x 1,080 (1080p Full HD)	NTSC	24p (23.976 fps)	12 minutes	~330 MB/min
	NTSC	30p (29.97 fps)
	PAL	24p (23.976 fps)
	PAL	25p (25 fps)
1,280 x 720 (720p HD)	NTSC	60p (59.94 fps)	12 minutes	~330 MB/min
	PAL	50p (50 fps)
640 x 480 (VGA SD)	NTSC	60p (59.94 fps)	24 minutes	~165 MB/min
	PAL	50p (50 fps)

Canon recommends using an SD card with at least a Class 6 rating to capture and playback movies.

Here are some examples of video from the Canon Rebel T2i, showing typical results under daylight conditions.

Canon Rebel T2i Video Samples
1,920 x 1,080, 30fps Programmed Exposure (12.2 seconds, 67.8 MB)	1,920 x 1,080, 24fps Programmed Exposure (10.4 seconds, 57.6 MB)
1,280 x 720, 60fps Programmed Exposure (10.8 seconds, 58.9 MB)	640 x 480, 60fps Programmed Exposure (11.8 seconds, 31.7 MB)
1,920 x 1,080, 30 fps 1/1,000 sec Manual Exposure (11.0 seconds, 60.4 MB)	1,920 x 1,080, 30 fps Programmed Exposure (10.3 seconds, 57.6 MB)
1,920 x 1,080, 24 fps Programmed Exposure (9.3 seconds, 52.7 MB)	1,280 x 720, 60fps Programmed Exposure (12.3 seconds, 63.6 MB)
640 x 480, 60fps Programmed Exposure (9.8 seconds, 25.9 MB)	1,920 x 1,080, 30fps 1/30 sec ISO 3,200 Manual Exposure (10.3 seconds, 54.7 MB)
1,920 x 1,080, 30fps 1/30 sec ISO 6,400 Manual Exposure (10.5 seconds, 59.2 MB)

Canon Rebel T2i Video-Mode Focusing

Unlike most other video-capable digital SLRs, the Canon Rebel T2i offers autofocusing during video recording -- but only in single servo mode. You can trigger a contrast-detect AF cycle either before or during a recording by half-pressing the shutter button, but depending on the lens and microphone in use, and the degree of focus adjustment required, AF noise is likely to be picked up on the audio track. (With the 18-55mm kit lens, and the T2i's internal microphone, AF noise is picked up very clearly as a high-pitched whine.) You can also manually focus the lens during a recording, and the true manual operation of AF on Canon's lenses means you can do this more or less silently, simply by being careful about turning the focus ring. (We recently tested the Olympus E-P1, which uses "fly by wire" focusing, whereby the focus ring only instructs the camera to move the lens elements rather than moving them directly via a mechanical coupling. This meant that small clicks could be heard on the audio track every time the E-P1 changed the focus setting, regardless of how slowly we turned the focus ring. With true manual operation of its lenses, the Canon Rebel T2i doesn't have this problem, although it's possible that a third-party or older Canon lenses might produce audible noise while their focus was adjusted.)

As we've noted in other SLR reviews, the good news with focusing for video is that you can get surprisingly good depth of field in video mode by stopping the lens down, thanks to the relatively low resolution of the video image. With a pixel resolution of only 2.1 megapixels in the Canon Rebel T2i's highest-resolution 1080p Full HD mode, 0.9 megapixels in 720p HD mode, and just 0.3 megapixels in VGA mode, images that would be unacceptably blurred as 18 megapixel still shots look perfectly fine as video frames. This not only provides greater depth of field at any given aperture, but is also more forgiving of diffraction limiting at very small lens apertures. Diffraction at small apertures means you'd usually want to avoid f/16 or f/22 for still images, but again, the results generally look perfectly fine at video resolutions. Bottom line, with the Rebel T2i's lens set to f/16 or f/22 (assuming you're shooting under fairly bright conditions), you'll be surprised by how little focus adjustment is needed during a typical video recording.

Canon Rebel T2i VGA Movie Crop

Another feature of the Canon T2i's movie mode that's not available on the EOS 7D is its VGA Movie Crop function, and indeed, we believe it to be unique among SLR and SLD movie modes from any brand at the time of this writing. The Movie Crop function aims to solve a problem faced by consumers, namely that expensive telephoto lenses generally carry hefty price tags that place them far out of reach of the casual amateur. Ordinarily, the Canon T2i's movies are recorded using data from across the image sensor area. With Movie Crop mode enabled, however, the T2i instead crops only the centermost pixels from its sensor data for recording, and discards the rest. The feature is only available when recording at VGA (640 x 480 pixel) resolution, and yields an effective 7x magnification.

There's no free lunch, of course. While magnifying your subject to bring you close to the action, the Movie Crop mode also magnifies image defects. Since lens defects are generally most prominent towards the corners, the crop mode avoids the worst of these issues by using the sweet spot at the center of the lens. The effects of focus errors, diffraction limiting, and high ISO noise can prove another matter entirely. Videos shot in the VGA Crop mode are decidedly soft compared to the standard VGA mode, and can quickly get noisy if ambient lighting isn't ideal. For the T2i's target market, though, such defects will likely prove relatively acceptable, when compared to the cost of obtaining a lens of equivalent focal lengths.

Canon Rebel T2i Video Exposure Control

Many video-capable SLRs only offer automatic exposure in their movie modes, but the Canon Rebel T2i gives you a choice of either automatic or manual exposure modes. In Auto mode, the camera adjusts the shutter speed and aperture as needed for a correct exposure, keeping things simple. 3.0EV of exposure compensation is available in 1/3 EV steps, to ensure exposure is as intended. Auto exposure mode is the default when you first place the Mode dial in the Movie position, and Manual mode is accessed from the Movie Exposure option in Movie Menu 2. In Manual mode, simultaneous control of both the shutter speed, aperture, and (optionally) the ISO sensitivity is possible. This is great news -- the ability to control depth of field or freeze action is very useful, giving you significantly more creative control over your videos. (Given the slow default shutter times of most video-capable digital SLRs, the T2i included, a higher shutter speed to freeze fast motion is almost a necessity for good-quality video of anything moving.) Note, though, that although you can control shutter speed, this doesn't prevent the so-called "Jello effect", more properly known as rolling shutter artifacts. Like other digital SLRs, the progressive manner in which the Canon T2i clocks data off its sensor means that sudden camera or subject movements can cause distortion, although this is less of an issue for the T2i than in some cameras.

Canon Rebel T2i Video: Audio recording

Like most competing SLRs with video recording capability, the Canon T2i sports an internal monaural microphone that can record an audio track. Internal mics are somewhat problematic, though, in that they're prone to picking up noise produced by moving your hands on the camera or actuating any controls while recording. We haven't noticed pronounced differences in how much camera-handling noise various models' internal mics pick up; the Canon T2i's seems fairly typical in that regard. In a big bonus for serious video users, the Canon Rebel T2i also sports a microphone jack under a rubber flap on its left side, to which you can attach an external stereo microphone. As of this writing, relatively few video-capable SLRs offer options for external audio input. In addition to its internal microphone and external mic jack, the Rebel T2i also allows audio recording to be disabled entirely through an option in Movie Menu 2.

Canon Rebel T2i Movie Recording User Interface

The Canon Rebel T2i's video mode is accessed via a dedicated position on the camera's mode dial. A Live View / Movie button to the right of the viewfinder is used to start and stop recording when the Mode dial is in the Movie position, and acts as a Live View button in other modes. Setting adjustments in movie mode are made via two dedicated Movie menus, which are only available when the camera is in Movie mode. Still images can be captured in Movie mode, interrupting the movie for about 1 second, by pressing the Shutter button. Since this is also used to trigger an autofocus cycle with a half-press, an option in the Movie menu allows autofocusing to be temporarily disabled by holding the the * button, enabling a still image to be captured during movie recording without first triggering an AF cycle. Autoexposure is used, unless manual exposure is chosen. Flash is not supported.

In Playback mode, the Canon T2i allows you edit out or trim the first and/or last scenes of a movie, in one second increments. You can save the trimmed movie to a new file (if there is space on the card), or choose to overwrite the original. Movies can be played back at normal speed, or in slow-motion, with adjustable playback frame rate. There are "VCR" like controls for advancing to the next or last frame, or playing from the previous or first frame.

Canon Rebel T2i Video Quality

As compared to the video from other cameras we've tested, we found the Canon Rebel T2i's video to be relatively immune to motion-induced compression artifacts that we've seen when recording in AVCHD mode (as noted, the T2i uses the broader H.264 spec). Its rolling shutter artifacts also don't seem quite as pronounced on some cameras, although they're still very evident when you pan the camera quickly while recording.

Rolling Shutter Artifacts

Essentially every video capable digital SLR currently on the market exhibits motion-related distortions called rolling shutter artifacts. These are caused because the image data is captured and then read off the chip sequentially by rows, rather being captured all at once. In the case of the Canon Rebel T2i, with its variable frame rate, this means that image data for the last row of a given frame is captured and read out anywhere from 1/24th to 1/60th second after the data for the top row was captured. The effect on moving objects is similar to that of a focal plane shutter in an SLR, but more pronounced, because the video frame is read out much more slowly than the slit of a focal plane shutter moves across the sensor.

For a camera that scans video frames vertically (as all do that we're aware of), rolling shutter artifacts will be most noticeable for subjects that are moving rapidly side to side, or when the camera itself is being panned horizontally. Verticals in the scene will appear tilted to the right or left, depending on the direction of camera motion. As an example, consider the case of a camera being panned from left to right, with a flagpole or other vertical object in the middle of the scene when recording for a particular frame begins: If the top of the object was centered horizontally when the first line of the video frame is acquired, by the time the last line of the frame has been captured, the bottom of the object will have shifted to somewhere left of center: As a result, the vertical object would appear to be leaning to the right.

The visual impact of rolling shutter artifacts on the Canon Rebel T2i seemed a bit less noticeable than in some other recent digital SLRs, but as noted, it's still a factor.

Exposure Curve

The Canon T2i's video exposure system operates either in a normal programmed-exposure mode, where the camera selects aperture, shutter speed, and ISO, or you can select Manual exposure mode via a menu option. Manual exposure mode is entirely manual, in that you're responsible for setting all three exposure parameters; there's no option for shutter or aperture priority. This can be a little challenging, if your light source is subject to variation, but it does give you the ultimate in control, and is a feature offered by relatively few video-capable SLR/SLD cameras.

While most consumer-level video SLR/SLDs on the market weight their exposure curve towards shorter exposure times, the Canon T2i's follows a different path, with its programmed exposure heavily favoring lower shutter speeds; on the order of 1/60 to 1/30 second. It turns out that this was a very deliberate choice by Canon, as the motion blur from the slow shutter speed makes for much smoother-looking video on playback. While detail in rapidly moving subjects is indeed blurred, that blurring helps merge the image from one frame into the next, giving the impression of more continuous motion. By comparison, if a video recording of fast action is made using very high shutter speeds, the result can be very choppy-looking, with rapidly-moving parts of the image appearing as multiple, crisp images. This effect is particularly acute at low frame rates such as 24 or 30 frames/second.

Recognizing this, Canon opts for video shutter/aperture exposure curves in its SLRs that try as much as possible to keep the shutter speed from rising much above the inverse of the frame rate, whether 24, 30, or 60 frames/second. When shooting in bright, sunny conditions, this can result in very small lens apertures, that in turn result in soft images due to diffraction limiting. When shooting the videos seen on this page of Charlotte chasing her Frisbee, I noticed that the camera was using apertures as small as f/29, even when set to the lowest ISO available. With a top video resolution of just over 2 megapixels, diffraction limiting is much less of a concern than when shooting at the Canon T2i's maximum 18-megapixel still image resolution, but even at video resolution, images shot at f/29 are going to look pretty soft.

Canon T2i Video Exposure Curve Examples
The Canon T2i's video exposure program is weighted toward slow shutter speeds. The significant blurring this produces with fast-moving subjects isn't nearly as evident in the live video as it is in the crop above: The video just looks "smooth" to the eye.	While the motion blur may actually help the visual appeal of the Canon T2i's videos, the tiny apertures required by the slow shutter speeds when shooting under full sunlight result in images that are soft overall. This crop is from a video shot in programmed exposure mode, with an auto aperture value of f/29. Tons of DOF, but nothing is really crisp.
In manual video exposure mode, you can select whatever combination of ISO, shutter speed and aperture you want. This crop is from a frame captured with a shutter speed of 1/1000th second. While the individual frames are very crisp, such a short shutter speed makes for rather choppy-looking motion.	The high shutter speed lets you use a more reasonable aperture, though, which makes for much sharper images. As long as you don't have fast-moving subjects in the scene, you aren't likely to notice the choppy motion, so the faster shutter speed may be a worthwhile trade-off, to avoid diffraction limiting.

The very smooth appearance of the Canon T2i's videos is perhaps worth the resolution trade-off when shooting under bright lighting, but a fairly strong neutral density (ND) filter should be considered an essential accessory, if you want to get the maximum video image quality when shooting in bright sunlight. Consider at least an ND 0.9 (3 stops of light reduction) for direct sunlight, and even more could be helpful. (ND filters are frequently sold in sets of three, with ND values of 0.3, 0.6, and 0.9. Such a set gives a total range of 1 to 6 stops of exposure reduction, in steps of 1 EV, and would make a good investment for a video enthusiast.)

Of course, the problem with an ND filter is that it makes the viewfinder image proportionately dimmer as well. A very dark ND filter could make it tricky to switch between video recording using the Live View display for framing and shooting stills with the optical viewfinder.

Low-light video with the Canon T2i

The Canon T2i takes full advantage of its high-ISO capability when recording videos: Its video auto-exposure curve will adjust the ISO as high as ISO 6,400, if necessary. You do pay a price, though, in that the video at ISO 3,200 is visibly noisy, and more so at ISO 6,400. That said, it's really pretty amazing that the Canon T2i's video is as clean as it is at such high ISOs.

One thing to note about low-light video recording with the Canon T2i: Exposure time is obviously limited by the frame rate. (You can't have a shutter speed of 1/30 second when the frame rate is 60 fps.) As a result, you'll get the best low-light results in one of the 1,080i resolution modes, because the frame rate at 720p and 480p resolutions is fixed at 60fps. The slower 30fps or 24fps frame rates of the 1,080i modes can make a real difference in how bright your videos are.

Canon T2i Video: Low-light examples
This crop is from a night scene under typical urban street lighting, captured in Auto mode. The camera indicated it was using ISO 3,200 for this clip, and the resulting video is surprisingly clean. Some noise is evident during playback, but it isn't nearly as bad as we had been expecting.	In manual mode, at ISO 6,400, there's visibly more noise (more visible during playback than in the static frame crop above), but it'd probably be tolerable for amateur use. Given that this is fairly typical urban lighting, the Canon T2i should be able to handle just about anything most consumers or amateurs would care to throw at it.
Switching to 720p mode results in much less light-gathering ability, thanks to the fixed 60fps frame rate. The shorter shutter time was just a reach too far for the T2i in this shot: The whole image is rather dark, and there's a lot more noise visible everywhere.	Dropping to 480p resolution helps slightly with the noise, but this light level really requires the slower 1/30 second shutter speed afforded by 1,080i recording.

Bottom line, while the Canon T2i may not have the low-light chops of its big brother the EOS 5D Mark II, it's a great performer within its price range.

Computer Requirements for Viewing HD Video

A typical computer these days has little trouble dealing with still images, but high-definition video can be another matter. Depending on the file format involved, it can take a pretty beefy computer to handle HD-resolution video playback without stuttering or dropping frames. The AVC / H.264 image compression used by the Canon Rebel T2i is one of the more compute-intensive formats, and its 1,920 x 1080 (1080p) resolution means there's a lot of data in each frame to deal with at full resolution. The net result is that you'll want a relatively recent and powerful computer to play full-res high-def video files from the Rebel T2i on your computer. At lower resolutions, the requirements will be more modest. We found that we could run the T2i's video acceptably at half size on an older G5 Power Mac with dual 2.3GHz processors, so long as nothing else was running simultaneously, so it definitely seems less processor intensive than full HD video from many other cameras, including some using Motion JPEG compression.

You can of course view your movies on a TV, either via the composite A/V Output, or on an HDTV via the HDMI output. Both terminals cannot be used simultaneously.

Canon T2i Video: Summary

With its broad range of options for resolution and frame rate (either 24 or 30 fps at 1,080i resolution, 60 fps at 720p and 480p), its choice of either auto or full-manual exposure control, its external audio input jack, and exceptional high-ISO capability, the Canon T2i is an unbeatable package for the video enthusiast shopping within its price range. For best results under direct sunlight, the enthusiast will want to pick up one or two neutral density filters to permit more reasonable lens apertures with auto exposure under direct sunlight, but the average consumer may not notice the softness produced by too-small lens apertures. At the other end of the exposure scale, the Canon T2i delivers excellent video quality in quite dim conditions, recording very usable video under typical nighttime city street lighting. Pure consumers (or still-photo enthusiasts just looking for easy, casual video recording) may miss the live (continuous) autofocus capability found in recent SLD-type models from Panasonic, Sony, and Olympus, but then the depth of field provided by the T2i's exposure curve gives enough depth of field to accommodate quite a range of subject motion. All in all, the Canon T2i delivers impressive video capabilities for its under-$1,000 price point.