Canon Rebel XTi Improvements and Enhancements

The Canon Digital Rebel XTi boasts a number of enhancements relative to the previous Rebel XT model, and its 10.1 megapixel sensor is arguably one of the least significant. Here's a list of what's new on the Rebel XTi.

• 10.1 megapixel Canon CMOS image sensor with improved cell layout and microlens array
• New EOS Integrated Cleaning System including Self Cleaning Sensor Unit and "Dust Delete Data" detection
• Large and bright 2.5 inch, 230,000 pixel LCD screen with wide (160 degree) viewing angle
• New, enhanced interface for camera settings with greatly extended display information
• Expanded Info screen with RGB histogram and memory card remaining capacity
• Continuous shooting at 3 frames per second, buffer depth of 27 JPEG Large/Fine or 10 RAW frames
• New folder management with manual folder creation and up to 9,999 images per folder
• Picture Style settings (same options as on EOS-30D)
• 9-point autofocus unit with high-precision f/2.8 support (same as on EOS-30D)
• Selectable AF modes
• Selectable AF points
• 3 settings for long exposure noise reduction, including auto
• Faster image processing
• Improved Print/Share functions
• Improved Direct Print functions including red-eye correction, face brightening and index printing
• Convenient image display functions including computer-only auto rotation and reduce/enlarge during quick review
• Additional Custom Functions
• Superior software package including Canon's exclusive Digital Photo Professional

The Tiny Flagship. Though it's their lowest price model, the Digital Rebel line has been something of a leader in terms of showcasing new features before they appear in Canon's higher-end cameras. The original Rebel came out in 2003 with improvements over the then lowest price digital SLR in the line, the EOS 10D. For $1,500 less, you got a slightly better sensor implementation in a camera that -- while having a few feature compromises -- served many consumers and intermediate photographers quite well. The Rebel XT played catch up with the EOS 20D in most ways, except that it was quite a bit smaller than that semi-pro shooter. But the Rebel XT did lead the rest of the industry in terms of high resolution at a low price, and its high ISO image quality remains unmatched for the current retail price in late 2006. The Rebel XTi plays both catchup and leader, adding features that other cameras have added in the past 18 months, like a bigger LCD and higher resolution, but also leads in areas others have yet to catch up. In terms of a comparison to other EOS cameras, the XTi is the low-price resolution leader, and includes sensor cleaning technology that no other EOS has. Following is a listing of the improvements as we reported them on the day of the Rebel XTi's announcement.

Sensor Improvements. Canon makes its own CMOS sensors, and the images they produce are hard to beat. In the case of the 10.1 megapixel chip in the Rebel XTi, Canon's claims that high-ISO performance will be very much on par with that of the Rebel XT and EOS-30D have proven true. The pixels in the Rebel XT's sensor are on a 6.4 micron pitch, while those in the XTi's sensor are spaced only 5.7 microns apart, the smallest pixels on an EOS digital SLR to date.

Smaller pixels generally mean less light-gathering ability per pixel. If you have less light, the camera has less information to work with, and is more likely to make errors, which we call noise. To counter the potentially negative impact of the XTi's smaller pixels, Canon engineers developed a more efficient cell layout that increase the percentage of each pixel's area that is devoted to light gathering (the pixel pads are bigger). They've also improved their microlens fabrication to reduce the gap between microlenses by a factor of two over their earlier designs (each pixel has a very tiny lens to gather light and focus it on the very small pixel pad that is sensitive to light). The net result is that the Rebel XTi's pixels have about the same light-gathering ability as the larger ones in the XT's sensor, despite their smaller physical dimension. The practical increase in resolution in going from 8 to 10 megapixels is pretty small, but it's nice to see that it's been accomplished with no loss in noise performance.

Huge/Bright/Wide Angle LCD Display Screen. The most immediately obvious change from the XT is the XTi's huge 2.5 inch, 230,000 color TFT LCD screen, a quite noticeable step up from the XT's 1.8 inch LCD. This is a very similar screen to that on the 30D and other recent Canon DSLRs, but a minor specification difference suggests that it's a different component: The viewing angle of other recent 2.5" displays on Canon DSLRs is specified as 170 degrees, while that on the new XTi is "only" 160 degrees. (A small difference that's largely academic relative to everyday use.) Important to note too, is that the 160 degree viewing angle spec applies to both vertical and horizontal directions, about an axis perpendicular to the screen. The screen on the Rebel XTi was configured to have most of its vertical viewing angle oriented in a downward direction. The bigger, wider view will help you show off your images to more people than the XT allowed.

Supporting the idea that this is an entirely new LCD component, Canon notes that the new unit has both a more transparent LCD and a brighter LED backlight. The net result is that the screen on the Rebel XTi is about 40% brighter at its maximum setting than the screens appearing on cameras like the EOS 5D and 30D. Canon does note though, that at its brightest setting, the screen's gamma changes to brighten the midtones. While making it easier to see under bright lighting, it does make the image look overexposed, and significantly washes out highlights. It's thus important to keep the screen brightness near the middle settings for critical evaluation.

Burst Rate and Buffer Depth. Some users may be disappointed to hear that the Canon Rebel XTi's burst performance is still the same as the Rebel XT's, at 3 frames/second, but this is just about right for a consumer camera, and compares evenly with most of the competition. It's important to note that this does represent an increase in data transfer rates, because the XTi has to handle data 25% faster than the XT, given the greater amount of data generated by the 2 million extra pixels. Where there is a performance improvement, though, is in the XTi's buffer depth: It can shoot 27 large/fine JPEGs or 10 RAW images before having to wait for the memory card to catch up, compared to 14 and 5 shots for the XT, respectively.

Dust Reduction Technology. The biggest news is Canon's new three-stage self-cleaning system. Other manufacturers have already addressed the dust issue, starting with Olympus, and now Sony has attacked it too. But Canon's solution takes multiple approaches. Internally, they've made modifications to keep key parts, like the shutter mechanism and even the body cap, from shedding dust. To further suppress dust, the surface has been treated with an anti-static coating to actually repel the menacing stuff.

Should those methods not work, the Rebel XTi's dust reduction system shakes the dust from the unique front plate of the camera's low pass filter, which sits in front of the actual image sensor. This knocks most of the dust off, where it will fall to one of the four sides and discover a very sticky adhesive to which it will hold fast.

The latter active portion of the new dust removal system runs every time you turn the camera on or off, but it isn't expected to introduce any power-on time delay. A small sparkle appears in the lower right corner of the Status display when the cleaning operation is being run, and a limiter will turn off the vibration function if the camera is powered on and off too often to keep the piezoelectric device from overheating. You can also interrupt the cleaning cycle by pressing on the shutter.

This first component of the low pass filter is also approximately one millimeter from the other part of the filter. This isn't so much to give the filter room to shake rattle and roll, but the air gap will let some light pass around smaller particles of dust, reducing its overall effect on images. 

Finally, a new function has been added to the Rebel XTi that allows you to manually map the dust on your sensor. Just point the camera at a white wall and the camera records a map of each particle's location over the sensor. This data is appended to the file and you can later subtract the dust using the included Digital Photo Pro software on a computer to remove it later. (See our expanded explanation under the Optics tab.)

New User Interface. The user interface on the new Canon Rebel XTi is one area where it differs sharply from past models. The small monochrome data readout formerly used to display shutter speed, aperture, and other camera settings has been dropped, to make room for the huge 2.5 inch color LCD screen. This means that the functions formerly served by the data readout have now moved to the large color screen, which becomes command central for camera operations. The basic operating controls (main dial, "cross" or arrow keys, and various other buttons) remain the same as in the XT, but those controls now control status indicators on the main LCD screen.

When you power up the Rebel XTi, the huge display screen immediately lights up, showing the current status of the major camera settings. This display remains on when the camera is active, except when the screen is being used to show menu options or an image is being played back. The display screen is turned off any time you bring your eye to the viewfinder, to save power and prevent the glare from the screen from interfering with your use of the viewfinder. (This last feature is reminiscent of DSLRs from Konica Minolta and Sony, which also use the main LCD screen for camera status display.) The large display screen can be turned on or off explicitly via the DISP button on the camera's back. A power lamp on the top of the camera tells you when the camera is on, a useful indicator if you've turned off the primary LCD.

The larger LCD screen allowed Canon to add eight new items to the status display relative to the previous XT model. These include ISO setting, AF frame display, White Balance adjustment, White Balance Bracketing, Red Eye Reduction Mode, Shooting Display mode, Beep, and something called "Dimmer Offset." Dimmer Offset refers to a variable display that can alternate between showing exposure compensation settings for either the internal flash or an external speedlight. The new user interface also takes advantage of the color LCD, using color changes to call attention to exposure compensation settings.

One downside of using a large color LCD screen for a basic camera status display is that a big full-color screen uses a lot more power than a little monochrome data readout. This is most likely why the Canon Rebel XTi's battery life is slightly less than that of the Rebel XT. (Frankly, we're surprised that the battery life isn't a good bit shorter than it is.)

Some things borrowed. As we mentioned, there's a lot of new stuff to ponder, but a lot of what's in the new Rebel XTi represents the best of Canon's latest innovations copied over from the EOS 5D and 30D.

Autofocus Improvements. Easily the most useful hand-me-down of the bunch is the 9-point AF system from the 30D. The key here is not the two extra points over the Rebel XT's 7-point AF, nor is it the diamond arrangement, it has to do with AF speed and accuracy. Our own informal testing showed the 20D and 30D to be far faster at locking focus than the Rebel XT, even though it is among the fastest we've seen. Now it's faster; and because it's identical to the 30D, it also offers the "dual-precision" center AF point found on the 30D.

Dual-precision AF points have two sets of focus sensors, one spaced to permit use with f/5.6 lenses, the other set to operate with f/2.8 lenses. Bottom line, when you attach an f/2.8 or faster lens to the XTi, the central AF point will automatically focus more accurately; no user intervention required.

Viewfinder Changes. The Canon Rebel XTi's viewfinder incorporates a couple of features from the viewfinder on the 30D, namely an FE lock (Flash Exposure lock) indicator on the left side, and a white balance adjustment indicator (+/-) on the right. The Red-Eye indicator icon is now displayed on the rear-panel LCD screen, so is not present in the viewfinder.

The nine AF areas from the 30D's AF system are visible, but they retain the look of the AF areas in the Rebel XT, a hollow box with a point in the center that illuminates bright red when the point is active.

Apart from these changes, the viewfinder appears to be essentially the same as that of the previous XT: Viewfinder blackout time is specified as 170ms for shutter speeds of 1/60 second or faster, dioptric adjustment ranges from -3.0 to +1.0, and the same Precision Matte focusing screen is used.

Picture Styles. The Canon Rebel XTi incorporates the Picture Style feature that first appeared in the EOS 5D and 1D Mark II N. Canon clearly intends to spread the concept across the SLR line. Picture Styles are an extension of the previous "Parameters" concept, basically combinations of presets for contrast, sharpness, saturation and color tone that tweak the camera's response to better suit various subjects or applications. Styles include Standard, Portrait, Landscape, Neutral, Faithful, Monochrome, and User Defined 1, 2, and 3. You can either directly modify the User Defined styles, or modify an existing Style and save it to a User Defined space. In the Monochrome Style, you can choose from an array of filters and tones to modify your monochrome output. Filters include Yellow, Orange, Red, and Green. Tones include Sepia, Blue, Purple, and Green. Each style's preset settings can be adjusted by the user, but the basic setups provide excellent starting points for various subject types, and fill somewhat the same role as different film emulsions did back in the days of chemical-based photography.

New Direct Printing Functions. As a major player in both image capture and printed output, Canon has always been a leader when it comes to making direct connections between their cameras and their printers. Like all their digital cameras, the Canon Rebel XTi supports printing to any PictBridge-compatible printer, but the XTi offers an expanded feature set that matches or exceeds the capabilities of the 30D. Here's a list of the printing capabilities added since the Rebel XT:

• 35-image "contact sheet" index printing
• Single-image prints with EXIF shooting information
• 20 image contact sheets with EXIF data
• Red-eye reduction function
• Face brightening correction function
• Additional supported paper sizes (4 x 8", 10 x 12", 8 x 10", 14 x 17")
• Improved printing effects (Natural, Natural M, B/W, Cool Tone, and Warm Tone added)
• Adjustment of printing parameters
• Addition of supported paper (Fine Art, Photo Rag, Super Photo paper)

Battery. The XTi's battery is the same as the XT's, the NB-2LH, but because of the larger display, its function as a Status display, and the new self-cleaning system, battery life is reduced. You can expect 500 images at room temperature (without flash) and 360 shots with 50% flash usage. At freezing temperatures, that expectation goes down to a still-respectable 370 and 280 shots without and with flash.

Handling and other details. The formerly anemic grip on the Rebel XT has been shored up a bit on the Rebel XTi, with just a little more to hold onto.

A small green LED has been added on the top panel of the camera to indicate power status, since the Status LCD is now gone. The new integrated Status LCD can go off before the camera actually sleeps, so the power lamp seems like a good idea.

Image sizes are 3,888 x 2,592 pixels, 2,816 x 1880, or 1,936 x 1,288, with Fine and Normal compression plus RAW and RAW+JPEG combinations.

Another benefit of the Canon Rebel XTi's very similar body style is that it uses the same battery pack as the XT, the BG-E3. Though it weighs a little more than the XT, at 510 grams without the battery or card (the best we can do at the moment), we found using this battery grip with the XT was a nimble combination. Since we like to shoot portraits, vertical grips are usually the first purchase we make with a new SLR. Given the Canon Rebel XTi's reduced battery capacity, the frequent shooter would benefit from this accessory.

The Rebel XTi kit comes with the standard EF-S 18-55mm f/3.5-5.6 (non-USM), and the camera is available in silver and black finish. This lens, by the way, is widely regarded as a quality, if cheaply constructed lens. The 10 megapixel sensor reveals some of its flaws, but it will still serve quite well for all general-purpose photography unless you zoom way in to inspect the pixels in the corners (like we do).

Canon has dropped one thing from the Digital Rebel XTi, and that's $100 off the price of both the kit and body-only cameras. The kit debuts at $899, while the body-only package is $799. The Rebel XT -- still a formidable camera in its own right -- will stay in the line for the rest of the year, with the price dropping to $799 for the kit and $699 for the body only. The Rebel XTi is expected to ship in mid-September.

Great timing. Now that all of Canon's major challengers have shown their cards, it's good to see the Canon Rebel XTi answer so many of the challenges presented. Adding a larger screen, more pixels, dust removal technology, and greater buffer depth meets several challenges presented directly by cameras like the Nikon D80, Sony Alpha A100, and Olympus E-500. Reducing the price of a camera that likely still leads in high-ISO image quality significantly raises the stakes.

Where Canon does not answer some of the challengers is in offering body-based image stabilization. Nor do they address the Nikon D80's inclusion of an impressively long focal length lens at a low price. However, Canon has long been a pioneer in image stabilization, and offers an array of image stabilized lenses, and they have a growing selection of EF-S lenses in addition to their 50+ lenses to choose from, all of which will work with the Digital Rebel XTi. I'm pretty sure Canon is sufficiently satisfied with their IS lens systems that they feel they've long ago addressed the issue. Answering the dust problem in such a comprehensive manner is a good step toward answering a real-world problem, though.