Canon T1i Video

We're seeing more and more video recording options on DSLRs, to the point that we expect it to become a relatively standard feature over the next year or two. The Canon T1i's video capabilities put it in serious competition with the more expensive Nikon D90, while at the same time falling short of the superior abilities of Canon's own EOS-5D Mark II. Here's a summary of what we found with the Canon T1i's video recording:

A Few Examples (Warning, large file downloads!)

Before getting into all the speeds and feeds, let's lead off with a few sample videos from the Canon T1i. The videos linked below were shot with a prototype T1i. As with still images, though, we've seen no discernible differences in video quality between the prototype and production samples we've tested. (NOTE that these are extremely large files: If you think you'll be inclined to want to refer back to them, please download copies to your local hard drive, to save our bandwidth!)

Canon EOS-T1i Video Samples
1920 x 1080, 20fps (42.9 MB)	1280 x 720, 30fps (26.1 MB)	640 x 480, 30fps (23.2 MB)

Resolution and Recording Time

The Canon T1i's movie resolutions include 1920 x 1080 (16:9), 1280 x 720 (16:9), and 640 x 480 (4:3). Assuming you're using a fast (class 6 or better) SD card, recording times are limited by file size, up to a maximum of 3.99GB. Recording time within this file-size limit will depend on both the resolution you're recording at and the amount of detail and/or motion in the scene you're shooting. Scenes with lots of fine detail compress poorly, which will shorten the maximum recording time. The same is true for scenes with a lot of motion, because MPEG encoding attempts to record only parts of the image that change from frame to frame.

We performed a very informal measurement of the Canon T1i's maximum recording times, shooting a scene with lots of detail but relatively little motion (the trees outside our office). This will probably be a reasonable indication of typical recording times consumers might see, as this subject had much more fine detail than average, but relatively little movement. To check the limiting case of a very simple, static subject, we also shot a movie of a blank, white wall, but only at the highest video quality setting. Here's a table showing what we found:

Canon EOS-T1i Maximum Video Recording Times
Resolution	Max time, High-Detail Subject	Max Time, No-Detail Subject
1,920 x 1,080 (20 fps)	12:30	14:30
1,280 x 720 (30 fps)	18:05	-
640 x 480 (30 fps)	24:24	-

Regardless of resolution or file size, though, there's an absolute limit on the Canon T1i's movie length of 29 minutes and 59 seconds. This odd limitation actually has nothing to do with the capabilities of the camera hardware, but is rather the result of European import tariffs: Cameras capable of recording 30 minutes or more of video are designated "video cameras" and subjected to a substantially higher tax rate. As a result, we're not likely to see many DSLRs capable of recording more than a half hour of video per clip anytime soon.

The Canon T1i records its videos as .MOV files, using MPEG-4 compression. The monaural audio track is encoded as PCM data, sampled at 44KHz. Where the 5D Mark II has both a built-in mic and a jack for connecting an external microphone, the Canon T1i offers only an internal mic, located on the front left side of the body (as viewed from the rear).

Shooting Stills While Recording Video

The Canon T1i has the (relatively) unique capability to shoot still images while the video is being recorded. If you press the shutter button while recording a video, the video recording will pause while the still image is captured, continuing seamlessly once the still image has been stored on the memory card. The video is saved in a single file, rather than breaking the recording into separate before/after segments. When you play back the resulting movie, you'll hear a simulated shutter sound on the video's audio track, and the video will pause for a couple of seconds, displaying a video-resolution version of the captured still image during the paused interval. The length of the pause is variable; several informal timings, we measured pause intervals ranging from 1.6 to 2.3 seconds, with longer pauses associated with higher resolution videos and still captures saved as RAW files. We found the pauses a little distracting visually, but were actually surprised that they measured as long as they did: When watching the movies, our sense was that they only lasted a second or so. We suspect that these brief pauses are something that we could get somewhat accustomed to, and might view them as an acceptable trade-off for being able to have both video and full-resolution still images simultaneously.

Quality, Frame Rate, and Motion Artifacts

At the highest resolution the Canon T1i's video frame rate is a somewhat sluggish 20 frames/second; fine for landscapes or scenes with relatively little movement in them, but really rather slow for any sort of action. Fortunately, both lower-resolution modes record at a much more usable 30 frames/second, and the 1,280 x 720 option still delivers excellent resolution. The Canon T1i's video mode also uses a rather slow shutter speed: We were told that it ranges from 1/25 to 1/30 second. You'll thus see a fair bit of blurring in videos with rapid motion, even at the higher 30 fps frame rate. (Rather than seeing a slightly jumpy stream of sharp images, you'll see a more or less continuous blur, as the subject essentially moves during the entire frame time.)

It appears to be a bit of a challenge to both capture and clock the video data off a DSLR-size sensor chip, as witness that we're seeing varying degrees of "rolling shutter" artifacts on video-capable DSLRs. What this refers to is that the DSLR captures video images one horizontal slice at a time, proceeding from top to bottom of each frame, taking one full frame time (e.g., 1/20 or 1/30 second, in the case of the Canon T1i) to capture and read out each frame. By contrast, most video cameras capture the entire frame in one relatively quick shot, and then transfer its data to memory while the active area of the sensor is gathering the light for the next frame.

The upshot of this rolling shutter is that the top of each frame is captured a full frame time before the bottom of that frame is. If part of the subject moves during that interval, there'll be an offset from top to bottom. If you pan too rapidly or jiggle the camera slightly while shooting, the subject will appear to sway or jiggle in the frame. This can be unsettling to your viewers; or humorous, if you're so inclined and the subject lends itself.

Click on the thumbnail above to see a brief segment of video from the Canon T1i, showing the rolling shutter artifact in the camera's highest quality video mode. (NOTE: 33MB download!) With a frame rate of 20 fps, the artifact is quite noticeable, but we think not quite as pronounced as that of the Nikon D90, where we first noticed this effect. At its lower resolution settings, the frame rate increases to 30 fps, and the "jiggle factor" decreases quite a bit. (Here are similar examples of rolling shutter artifacts at 1,280 x 720 (19.2 MB) and 640 x 480 (12.9 MB) - Please go easy on our bandwidth, with these...)

There's some argument over how much of an issue these rolling-shutter artifacts actually are, during normal recording. You'd certainly never want to pan a video camera as quickly as we did in the examples above: You'd make your audience sea-sick! On the other hand, you may need to pan that quickly if you're tracking a very fast-moving subject. Less-experienced users may also have trouble with minor jiggles and twitches as they hold the Canon T1i and pan; it takes some skill and practice to be able to pan really smoothly with a hand-held camera. There's a reason pros use expensive fluid heads on monster tripods, to get smooth panning! Wherever you come down on the issue, the Canon T1i's 720p video does relatively well in this area. (And the slow frame rate of its 1080p video pretty much mandates slow, careful panning, if you don't want to end up with significantly blurred or jumpy video.)

User Interface

The Canon T1i's video mode is accessed differently from that in the EOS-5D Mark II, in that it has its own icon on the Mode Dial, rather than being accessed from within normal Live View mode. This helps some with the user interface, in that the SET button now accesses the Quick Menu, rather than starting/stopping recording as in the 5DmkII. On the Canon T1i, video recording start/stop is controlled by the Print/Share/LiveView/Video button just up and to the left from the arrow-key circle. It's a very convenient arrangement, and we found the Quick Menu very handy for adjusting commonly used settings

In-camera image adjustment

When capturing still images, the Canon T1i offers a sophisticated array of image processing to correct for lens limitations (Lens Peripheral Correction) or help with difficult lighting (Advanced Lighting Optimizer and Highlight Tone Priority). It also has very sophisticated algorithms for reducing noise in high-ISO images. Of these, only Lens Peripheral Correction is available when shooting videos. This feature corrects for the shading (more commonly but less accurately called "vignetting") that often darkens the corners of images shot with wide-angle lenses. The LPC feature in the Canon T1i almost entirely eliminates this effect, and it's applied in real time to both Live View viewfinder images and videos.

ALO and HTP would both be very welcome features in videos, as harsh lighting is every bit as problematic for videos as still images. Both of these enhancements appear to require considerable processing, though; too much to be done on the fly during video recording.

More disappointing was the lack of any control over either shutter speed, lens aperture, or ISO during video recording. As Shawn pointed out in the User Report section of this review, the lack of autofocus during video recording makes depth of field all the more important. Shooting the clips of Marti throwing the Frisbee for IR mascot Charlotte, I found myself greatly wishing that I could just stop down a little to get more depth of field. It was bright daylight, there was plenty of light around, but with no control over the aperture, I had to just accept the fact that Charlotte was going to go in and out of focus somewhat as she chased and retrieved the toy.

Happily, the Canon T1i does give you control over at least one critical image parameter during video recording: The exposure adjustment control remains active during video recording, so you can adjust exposure up or down as needed. (Note, though, that the sound of you manipulating the camera's controls will almost certainly be heard on the video soundtrack.)

Computer Requirements for Viewing HD Video

Fair warning: Purchasing a Canon T1i may very well be lead to you buying a new computer, or at least a new graphics card! Viewing 1080p MPEG-4 compressed video on a computer demands a surprising amount of processing horsepower: If you notice hiccups and jerks while playing back either 1,920 x 1,080 or 1,280 x 720 video on your computer, don't blame the camera! My day-to-day work computer is a 2.3 GHz dual-processor Power Mac G5, certainly no slouch in the CPU department. When I first played back a 1,920 x 1,080 video on it, though, I was convinced that the Canon T1i had problems with its video encoding. The particular scene I was looking at had some slowly waving tree branches in the foreground. When played back on my G5, the branches would move smoothly for a little bit, then suddenly jerk to a new position, moving slowly again afterward. This would happen perhaps a couple of times per second, and was very distracting. Fortunately, the problem had nothing to do with the Canon T1i, but proved to be merely a case of an aging computer struggling to cope with modern technology. Played back on my MacBook Pro (also aging now, but with a 2.16 GHz Core 2 Duo processor), or on Shawn's iMac (2.4 GHz Core 2 Duo), the videos were perfectly smooth.