Canon XTi Review

Canon Rebel XTi Design

Here are a few shots of the Canon Rebel XTi, some captured by us, others courtesy of Canon USA, Inc. These should give you a pretty good idea of what the camera looks like (inside and out).

The obligatory front 3/4 view from Canon, of a black Rebel XTi…

And here’s a shot of the silver Rebel XTi. Canon calls this color “Chrome,” and it has a very different finish from the original Rebel or XT. It’s hard to describe, but it’s very nice looking. The largish-looking lens in this shot is the 17-85mm EF-S IS lens, a neat lens with a useful focal length range and image stabilization in a surprisingly compact package.

Here’s a really cool see-through rendering of the Canon Rebel XTi. Click the image to see a larger version. If you’d like to make a wall poster of this shot, here’s a really huge version of the image!

The front of the Canon Rebel XTi features the EF and EF-S compatible lens mount. On the outside edge of the lens mount is the red dot for lining up standard EF lenses, as well as a white square, corresponding to the same alignment icon on the new EF-S lenses. There’s also the lens release button and the redeye reduction lamp (the frosted window at upper left in the view above).

Left and right views. You can see the Canon Rebel XTi’s Flash release, Lens release, and DOF preview button on the left side, just the CF compartment cover and the rubber door to accomodate the cord from the optional AC adapter’s dummy battery.

The back of the Canon Rebel XTi is where it all happens, from an operational standpoint. The back panel control layout is very similar to that of the Rebel XT, but there are a few changes. The Menu and DISP button positions are swapped, the DISP being the new name for the INFO button on the XT. The button still cycles through display modes, but also turns the main shooting display off if you so desire.

Of course, the biggest difference is the increased size of the color LCD (2.5 vs. 1.8 inches for the XT), which has forced them to eliminate the separate monochrome Status LCD. Also visible is the Rebel XTi’s IR sensor just below the optical viewfinder.

You can also see the Canon Rebel XTi’s thumb-grip pad in the upper right, and the sculpted ridge along the right side that gives your thumb much more secure purchase than on the original XT.

The Canon Rebel XTi’s connector compartment, essentially identical to the one on the Rebel XT.

The top of the Canon Rebel XTi features the Shutter button, Mode dial, Main dial, and Power switch. The pop-up flash compartment is just behind the lens. The top of the camera also contains a hot shoe for mounting an external flash unit. The Rebel XTi’s hot shoe has the usual trigger terminal in the center, as well as four other contacts for interfacing to Canon EX Speedlite flash units, and a hole for a locking pin to prevent rotation of the speedlight. Fixed neck strap eyelets are located on both sides of the Canon Rebel XTi’s top panel as well.

One of the more significant design changes is in the grip design. This shot exaggerates the size difference in the grip of the Rebel XTi (on the right). The camera body itself is about a millimeter thicker than the XT’s, and the front grip protrudes about 3mm further from the camera body than does the grip on the XT. The actual size difference is really minimal, but the difference in comfort and security is huge.

The very flat bottom of the Canon Rebel XTi reveals the metal tripod mount, as well as the main NB-2LH Lithium Ion battery chamber cover. The main battery compartment cover is removable, necessary when installing the optional vertical grip on the camera. A small latch lever at the outside edge of the battery chamber cover unlocks it so that it may be opened. Also inside the compartment is the slot for the CR2016 3V battery that keeps the camera settings in memory when the main battery dies. The battery compartment cover is far enough from the tripod socket that you should be able to swap batteries without removing the camera from your tripod mount. The large surface area of the Canon Rebel XTi’s bottom provides a stable mounting surface for use with a tripod, even with fairly large lenses attached.

Canon Rebel XTi Operation

The Rebel XTi has a very different user interface than previous Digital Rebel models. It discards the black/white data readout found on the original Rebel and Rebel XT, instead relying on its large color LCD screen for all user interaction. This makes for a very clear, highly visible user interface, but probably does contribute to slightly shorter battery life, since the large LCD has to be fired up any time you want to change a setting. One feature we do like very much though, is the infrared face-detection sensor that turns off the LCD screen when you hold the camera up to your eye. (The Nikon D40 lacks such a sensor, something we’ve found somewhat annoying when working with it.)

Overall, the control layout places a few main controls (power, shutter button, command dial, and mode dial) on the right side of the camera’s top panel, with most of the other controls on the back of the camera. Let’s take a closer look at some of the user-interface elements:

Canon XTi Rear-Panel LCD Display

We mentioned the new rear-panel display in the overview, let’s take a closer look at it. The image below shows callouts for all the information shown in the default display. (Illustration courtesy Canon USA.)

The display is black-and-white, except for the light-grey box around the Shooting Mode indicator. We were a little surprised that we didn’t see more use of color in this display, but the monochrome approach does have a certain elegance to it, and all the information is very easy to decipher.

One time when color is used on the rear-panel display is when you adjust the exposure compensation. As soon as you press the exposure compensation button on the camera’s body, the exposure compensation area is highlighted on the LCD display, as seen above.

	Top: ISO
Left: Metering Mode		Right: AF Mode
	Bottom: White Balance

Pressing any of the arrow keys to the right of the LCD screen immediately brings up a screen for the exposure parameter associated with that button. Once the option screen is displayed, you can use the arrow keys to scroll the cursor highlight through the options presented. When you’ve made the choice you want, pressing Set confirms it and returns you to the main shooting display. A nice feature on the XTi is that you don’t have to press the Set button to confirm a setting before shooting: If you just hit the shutter button, the camera will snap a picture, using the setting you left the cursor on. One odd aspect is that some of these buttons work differently from the others. For example, when you press the ISO button it brings up the ISO menu. Press the button again, and it scrolls up through the options. You can also use the four arrows to navigate within the list, jumping from ISO 100 to ISO 800. However, when you press the center or OK button, you get a similar list, but you can’t scroll with anything but the up and down arrows, or else the Main Dial. Same look, different behavior.

The AF-point selection screen is also very clear and straightforward. When you press the AF-point selection button in the upper right corner of the back panel, the display shown above appears. As you’d expect, you can use the arrow keys to select the point you want, and then exit by pressing either the Set or Shutter button.

The Picture Style and Drive Mode displays are equally clear, though selection is not quite as simple (mostly because the Set and Drive mode buttons aren’t navigation buttons; but the interface is different enough that it’s noticable)…

A final camera-status option has been carried over from the Rebel XT, namely the Camera Function display, shown below. This display is accessed by pressing the DISP button while any settings menu is displayed. This screen shows the status of a large number of camera settings, including date and time, Picture Style settings (sharpness, contrast, saturation, and color tone), color space, white balance correction and bracketing, auto power off, auto rotate, LCD monitor auto off, and remaining capacity on the CF card. This display can be a little bewildering to new users, but it’s a great way to quickly check whether you may have forgotten to clear (or set) some of the more obscure Picture Style or White Balance options.

Canon XTi Playback & Record Review Displays

As is the case with most DSLRs, the Canon Rebel XTi’s rear-panel LCD screen can’t be used as a live viewfinder. It does, however, show by default each image as it’s captured. The display mode used in Record Review is the same as was last used in Playback mode, or you can hit the DISP button to cycle to a different mode. Likewise, in Playback mode, you can cycle between the available display options by pressing the DISP button repeatedly. You can also select between the normal luminance-based histogram and the new RGB histogram option via a Playback-mode menu item. The screenshots below show the various displays and options available.

Canon XTi Image Display Options
This is the default display in playback mode. The file number is displayed upper right, the shutter speed, aperture, and file sequence number is shown below left.	Pressing the DISP button cycles through the three available displays. This is the second option, image with no overlay.
The XTi’s third playback display option shows a histogram and more detailed exposure information. If there are any blown highlights, they’ll blink in this mode.	A Custom Settings Menu option lets you choose between a conventional luminance-only histogram, or the separate red, green, and blue displays as seen above.
You can also zoom in on an image, up to 10x at the highest resolution. The small navigator window in the lower right-hand corner shows you what part of the larger image you’re currently viewing. The arrow keys let you navigate around the full image, and the zoom in / zoom out keys increase or decrease the magnification level.
If you press the Zoom Out button while viewing a single image on the LCD screen, it’ll take you to a 9-imge thumbnail display. The arrow keys let you navigate among the thumbnail images. The overlay text displays the same basic exposure info for the currently-selected image as does the default single-image display.	Pressing the JUMP button takes you to a thumbnail display, but one that lets you skip through pages of nine thumbnails at a time.
Pressing the JUMP button when a single image is displayed gives you the option of skipping through the images on the card in steps of 10 or 100 at a time, or skipping based on shot dates.	Pressing the Delete button brings up this display, giving you the option to erase the current image, or all (unprotected) images on the card. The Delete display will show either the full image or a thumbnail plus histogram, depending on the playback mode you’ve selected.

Canon Rebel XTi Optics

Lens Compatibility

Like other Canon DSLRs with sub-frame sensors (currently, the Canon Rebel XTi and Canon EOS-30D), the Canon Rebel XTi will work with pretty much any EF-mount lens ever made, as well as with the special EF-S lenses designed for cameras with APS-C size sensors. Designed with a smaller image circle (the area covered by the image on the film/sensor plane), EF-S lenses tend to be smaller and lighter than full-frame models with the same focal length and maximum apeture. EF-S lenses can’t be used on full-frame Canon cameras (nor on their models with 1.3x crop factors, like the current EOS-1D Mark II N), but small-sensor cameras like the Rebel XTi can use any full-frame lenses in Canon’s arsenal.

The sub-frame sensor on the Canon Rebel XTi means that it has a smaller angle of view (by a factor of 1/1.6x) than a full-frame camera with any given lens. While most properly called a “crop factor”, the 1.6x ratio is most commonly referred to as the “focal length multiplier” since that’s how it works in practice: Any lens used on the Rebel XTi will have the same field of view as one with a 1.6x greater focal length will when attached to a 35mm camera. (For example, a 100mm lens on the XTi will show the same field of view as a 160mm lens on a camera with a 35mm frame size.) This means that the 18-55mm kit lens for the XTi has a coverage roughly equivalent to that of a 29-88mm lens on a 35mm camera.

Like most kit lenses, the 18-55mm f/3.5-5.6 lens that ships with the Canon XTi is of only modest quality, being designed for low cost more than optical excellence. It will work well enough for average consumer-level shooting, and can actually be quite sharp when stopped down to f/8 or so, but a better lens is one of the first accessories new SLR owners typically buy. (See our sister site SLRgear.com for in-depth lab tests and user reviews of SLR lenses.)

Autofocus Improvements

It’s clear that the Canon Rebel XTi has borrowed a lot of technology from the EOS-30D. One place where this is dramatically obvious is in its autofocus system: The Rebel XTi has the same AF system as used in the 30D. This means it sports 9 AF points vs the Rebel XT’s 7, and also offers the “dual-precision” center AF point found on the 30D. (A shot of the AF sensor used in both the XTi and 30D appears at right, image courtesy Canon USA, Inc.)

What does “dual-precision” autofocus mean? SLR autofocus accuracy is governed in part by how far apart you can space the sensor elements for a single AF point from each other. The wider this “baseline,” the more accurately the AF point can determine focus. What limits the AF baseline spacing in a camera system is the lens aperture. You can build sensors with wider baselines, but that also restricts the range of lenses they can be used with. By and large, camera manufacturers have set f/5.6 as the minimum aperture their AF systems will work with. Lenses with wide-open apertures smaller than f/5.6 just won’t focus. But once the baseline spacing is set, using a faster lens doesn’t improve focus accuracy any.

On their higher-end DSLRs, Canon uses special AF sensors for some of the AF points. These 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. Since an f/2.8 lens permits almost a 2x increase in baseline spacing, AF precision increases proportionately when using them.

As on the EOS-30D, the Canon Rebel XTi’s central AF point uses a dual-precision focus sensor. Whenever you attach an f/2.8 or faster lens to the XTi, the central AF point will automatically focus more accurately: No user intervention is required.

The AF points on the Rebel XTi cover about 60% of the frame width, and about 50% of the frame height. The illustration above shows the relative spacing between the various AF points, with the distances between them marked in millimeters, at the focal plane. (Illustration courtesy Canon USA.)

AF-Assist Illuminator

Like the original Digital Rebel and Rebel XT before it, the Canon Rebel XTi uses the built-in flash head as its AF-assist illuminator, rather than a bright light built into the camera’s body. This works well (as you’d expect, the flash is quite bright, and probably has a longer range than an on-body illuminator bulb), but the Rebel XTi shares the limitation with its predecessors that the AF-assist option is only available when a flash is in use (whether internal or external). That is, you can’t use the AF-assist illuminator and also make an available-light exposure. If you attach a 550EX external flash unit to the Rebel XTi, its internal infrared AF-assist illuminator can be used instead of the flash head itself, providing a useful working range of about 50 feet with a less obtrusive light source. This AF-assist is still only available when the flash is enabled, though. For non-flash photography, Canon’s ST-E2 wireless sync transmitter can apparently also be used for AF assist, a handy trick. The ST-E2’s AF-assist light has a useful range of about 25 feet. (Note though, that we haven’t tested the ST-E2 ourselves, so can’t verify this performance independently.)

Dust Reduction Technology

One of the major innovations introduced in the Rebel XTi is Canon’s system-wide approach to reducing the impact of dust on the image sensor. From the beginning, every DSLR has offered a sensor-cleaning mode, in which the mirror is locked up and the shutter opened to permit the sensor to be cleaned with compressed air, a solvent-carrying swab or other means. As the market has matured and more DSLRs have found their way into the hands of novice users, it has become clear that some automated way of dealing with sensor cleaning is needed.

Consumer point and shoot digital cameras have no trouble with dust because their lenses and sensors are assembled together in a cleanroom environment at the factory. Once assembled, there’s no path for dust from the outside world to make its way onto the sensor surface. A key feature of Digital SLRs however, is the ability for the user to easily swap lenses. This expands creative options enormously, but every time the lens is removed, dust from the environment is free to enter the camera body. From there, it’s only a matter of time before some of it makes its way to the surface of the sensor where it casts shadows that appear as dark blobs in your images. (Properly speaking, it’s the anti-aliasing filter that collects dust, rather than the sensor itself, but common parlance refers to “sensor cleaning.” For the sake of familiarity, we’ll generally refer to sensor cleaning here, but will make mention of the anti-alias filter as seems appropriate.)

The principal approach other manufacturers have used to deal with dust has been to make the system self-cleaning, by rapidly vibrating either the anti-aliasing filter itself or a protective cover glass lying above it, to shake loose adhering dust particles. Once dislodged, a strip of sticky materia at the bottom of the sensor cavity or mirror box catches and holds them. This approach was pioneered by Olympus, but has recently been adopted by Sony as well, in their DSLR-A100 model.

In typical fashion, Canon’s camera engineers took a deeper look at the issue of sensor contamination, and have come up with a multifaceted, system-wide approach to reducing the impact of dust on users’ photographs.

Canon’s approach uses a vibratory cleaning method as a primary part of the overall strategy, but they’ve introduced several refinements as well. Here’s what they’ve done:

Shooting Priority: Shutter Button Overrides Cleaning Cycle

It’s critical for a digital camera to power up and be able to capture the first shot quickly, to avoid missing the action when first starting up. Some cameras with integrated cleaning systems can take a second or two for the cleaning cycle to complete before they’re ready to capture an image. To avoid this problem, the Canon XTi aborts its normal power-on cleaning cycle as soon as the user touches the shutter button. This insures that you won’t miss a critical shot

Special Shutter Coating/Construction

It turns out that only some of the dust that appears in DSLR images comes from outside the camera: As they age, normal wear and tear can make shutter curtains shed microscopic particles that eventually end up on the sensor. In the Rebel XTi, Canon has introduced a special shutter-curtain coating designed to greatly reduce the shedding of particles.

Along with the specially treated shutter, Canon has also begun using a different plastic in their DSLR body caps, one less prone to creating shavings that can drop into the mirror box.

Split Anti-Aliasing Filter

Rather than introducing a separate cover glass into the optical chain, Canon has split the XTi’s anti-aliasing filter into two parts. One element sits right above the sensor, while the other is positioned further away. It’s this outer element that’s vibrated during the cleaning cycle.

In describing the technology, Canon notes that the outer anti-aliasing element is positioned further from the sensor surface (a millimeter or so) than is normally the case. This greater distance reduces the effect of any dust that does adhere, by making the shadow cast by each dust particle larger and softer-edged.

Anti-Static Coating

To make it harder for dust to gain a foothold in the first place, the outer anti-alias filter element bears an anti-static coating. Dust particles frequently carry static charges, so the anti-static coating avoids one of the key mechanisms by which dust particles adhere.

Dust Delete Image Processing

No matter how good an automatic cleaning system, there are going to be some stubborn dust particles that it can’t dislodge. To deal with these, the Canon XTi has the ability to shoot a dust reference photo, and then transfer that information to Canon’s Digital Photo Professional software, which can use it to eliminate the shadows cast by dust particles on the images.

This sort of image processing to eliminate dust isn’t an entirely new development, it’s been a feature of Nikon’s Capture software for some time. Canon’s implementation has some additional wrinkles that make it somewhat more useful. Primary among these is that Canon’s “Dust Delete” processing works for both JPEG and RAW format files. (Nikon’s works only with RAW images.) This really expands the utility of the anti-dust processing, and makes it more accessible to amateur users who shoot exclusively or primarily in JPEG format.

Canon’s anti-dust approach is also different in that the dust map (“Dust Delete data”) that the software uses to perform its magic is stored in the headers of the JPEG or RAW files created by the camera. There’s thus no need to keep track of a separate dust image file, the information is always available in the file headers, assuming you’ve actually performed the dust-mapping process. You can update the Dust Delete data any time you think the camera might have been exposed to dust, or after you’ve manually cleaned the sensor. The latest dust map is automatically incorporated into the EXIF headers of all JPEG images, or the headers of any RAW files. While we don’t have any technical details on how the dust map is stored, Canon claims that the encoding scheme used for it is very efficient, so the dust map information adds very little to the file size.

The screenshots above show the steps in capturing a Dust Delete reference image. Starting in the upper left from Shooting Menu Screen 2, selecting Dust Delete Data produces a screen that shows when the last Dust Delete reference image was captured. Selecting OK on this screen initiates a cleaning cycle, after which the camera prompts you to take a picure of a blank white surface. (The camera automatically defocuses the lens and sets the aperture appropriately, to produce the best possible dust image.) The camera then processes this data, and reports whether it was successful or not. If the surface you used to capture the image wasn’t sufficiently uniform, you’ll get an error message, but if the image was good, you’ll see the confirmation screen as shown above in step 6. The Dust Delete Data just generated will now be included in the headers of any JPEG or RAW images captured, until you decided to capture a new dust reference image.

We don’t have any quantitative way of evaluating dust-removal systems, but based on Canon’s description of it, their anti-dust technology does appear to go a step or two beyond anything else currently on the market, providing a more comprehensive solution to the problem of dust in DSLR images than we’ve seen to date.

Lens

Zoom
Good performance, 3x zoom with the 18-55mm kit lens.

18mm	55mm

The Canon EOS Digital Rebel XTi’s 18-55mm kit lens performed very well here, with sharp results at full wide angle. Coma distortion is low, but some corner softness is visible in the lower left corner of the frame. Results were also quite good at the 55mm full telephoto setting, without any noticeable distortion. With the exception of the slight softness noted in the lower left corner of the wide angle shot, these images are sharp. This is to be expected though, as the lens was stopped down to f/8, so both shots are well within the “sweet spot” of the lens’ operating parameters.

Macro
The 18-55mm kit lens captures a fairly small minimum area with strong detail and high resolution. The flash illuminates the target, but with uneven results.

Standard Macro	Macro with Flash

Macro performance will depend on the lens in use, but the Rebel XTi’s 18-55mm kit lens performed well, capturing a small minimum area of 2.58 x 1.72 inches (66 x 44 millimeters). Detail and resolution were both very good, and though details are slightly soft throughout the frame, additional corner softness isn’t overtly noticeable. The camera’s flash underexposes the frame a little, with some falloff in the lower portion of the frame. For the best results, an external light source or macro ring light is recommended when you’re shooting this close.

Distortion
Moderate barrel distortion, though low pincushion with the kit lens.

This is the tendency for the lens to bend straight lines outward (like a barrel — usually at wide angle) or inward (like a pincushion — usually at telephoto). The Rebel XTi’s 18-55mm kit lens produced about 0.76% barrel distortion at wide angle, which is about average among the cameras we’ve tested (although still a little high in my opinion). At the telephoto end, the lens produced about 0.10% distortion, which is fairly low.

Barrel distortion at 18mm is 0.76%

Pincushion at 55mm is less than 0.10%

Chromatic aberration
Moderate, a little high at wide angle, virtually none at 55mm.

18mm: moderately high and bright, top left @ 200%	18mm: a little bright, top right @ 200%
55mm: lower and less bright, top left @200%	55mm: low, top right @200%

Chromatic aberration is on the high side at the full wide angle setting of the Rebel XTi’s 18-55mm kit lens, showing about 15 pixels of very bright coloration on either side of the target lines. At the 55mm telephoto setting, some coloration is present, but colors are so faint that the effect isn’t really very noticeable. (This distortion is visible as a very slight colored fringe around the objects at the edges of the field of view on the resolution target.)

Corner Sharpness
Soft corners with the lens wide open (center is less sharp wide open as well).

18mm: Quite soft in the top corners (upper right)	18mm: Sharper at center, but still not great
55mm: Also soft in the top corners (upper right)	55mm: Sharper at center, but still soft

The Canon EOS Digital Rebel XTi’s 18-55mm kit lens produced rather soft corners in a some shots when it was wide open, with the most noticeable effect in the upper right corner at both wide angle and telephoto. It was also less than perfectly sharp in the center wide open, but both center and corners improve greatly when it’s stopped down. (Pretty typical for a kit lens.)

The images above were taken from our standardized test shots. For a
collection of more pictorial photos, see our
Canon EOS 400D Rebel XTi Photo Gallery
.

Canon Rebel XTi Exposure

The Canon Digital Rebel XTi provides as little or as much exposure control as you could want. Standard exposure modes include the usual Program, Aperture-Priority, Shutter-Priority, and full Manual modes, as well as some “Image Zone” (scene-based preset) modes, and an Automatic Depth-of-Field mode. The “Image Zone” exposure modes include Portrait, Landscape, Close-up (macro), Sports, Night Portrait, and Flash Off modes. These modes preset a variety of camera parameters to make it easier for non-expert photographers to achieve good exposures in a variety of standard shooting situations. The Flash Off mode simply disables the flash and external Speedlite (if attached), and puts the camera under automatic exposure control. The full Auto mode takes over all camera functions, turning the Canon Rebel XTi into a very easy to use point and shoot camera, albeit a very capable one.

The Aperture Priority and Shutter Priority modes work much the same as on any other camera, allowing you to adjust one exposure variable while the Rebel XTi selects the other for the best exposure. Program mode keeps both variables under automatic control, while Manual mode gives you full control over everything. The Automatic Depth-of-Field mode (A-DEP) uses all nine autofocus zones to determine the depth of field in the active subject area. Once the Rebel XTi has determined the range of focusing distances present across the nine zones, it automatically computes the combination of aperture and shutter speed needed to render the nearest and furthest points in sharp focus.

Canon Rebel XTi Metering & ISO Options

Exposure metering options are similar to the 300D and 350D models, with Evaluative, Partial, and Center-Weighted options. The Canon Rebel XTi offers variable light sensitivity, with ISO equivalents of 100, 200, 400, 800, and 1,600. For adjusting the exposure, the XTi’s Exposure Compensation setting increases or decreases overall exposure from +/-2 EV in one-third or one-half EV increments. (You set the step size through the Custom menu.) An automatic exposure bracketing feature lets you set the total exposure variation (across three shots) at anywhere from +/- one-third or one-half EV all the way up to +/- 2 EV. The nice part is that the automatic variation is centered around whatever level of manual exposure compensation you have dialed in. Thus, you could manually set a positive exposure compensation of 0.7EV, and then have the camera give you a variation of +/- 2/3 EV around that point.

AE/AF Lock

Another feature deserving comment is the Rebel XTi’s separation of the autoexposure and autofocus lock functions. In consumer-level digital cameras, half-pressing the Shutter button locks exposure and focus simultaneously. You can use this to deal with an off-center subject by pointing the camera at the subject, locking exposure and focus, and then reframing the picture before finally snapping the shutter. The only problem is that you sometimes need to perform a more radical recomposition of the subject in order to determine the proper exposure. For instance, you may want to zoom in on the subject, grab an exposure setting, and then zoom back out before taking the picture. Situations like that require locking the exposure independently of the focusing, and the Canon Rebel XTi provides for just such eventualities by way of a separate AE lock button on the back of the camera, right under your right thumb. Through the Rebel XTi’s Custom menu, you can specify the operation of the AE Lock button, as well as the AF/AE locking function of the Shutter button. A very handy feature indeed.

White Balance Options

The Canon Rebel XTi offers a full range of White Balance settings, including six presets, an Auto setting, and a Custom setting. The six presets include Daylight, Shade, Cloudy, Tungsten, Fluorescent, and Flash. The Custom setting bases color balance on a previous exposure, meaning you can snap an image of a white card and then base the color temperature on that image. A White Balance bracketing option snaps only one image, then writes three successive files from that single image. Bracketing steps are from -/+ 3 stops in whole-stop increments. (Each stop corresponds to five mireds of a color conversion filter, for a total range of +/- 15 mireds. This corresponds to about a +/- 500K shift at a normal daylight color temperature of 5,500K.)

The WB Bracketing is set on the same grid as the White Balance correction grid. Fairly sophisticated, the white balance correction tool lets you shift the color balance toward more or less green, amber, magenta, or blue, using a +/-9 step grid format. You move a highlighted square through the grid to adjust the color balance. It’s a slightly more advanced interface than I’m used to seeing on digital cameras, but a useful one that greatly extends the camera’s color corrective abilities.

The Rebel XTi also offers a Picture Style option through the LCD menu, which lets you select from Standard, Portrait, Landscape, Neutral, Faithful, Monochrome, or three User Defined settings. In each of the preset modes, the contrast, saturation, sharpness, and tone are set for specific conditions. The three User Defined options let you manually adjust each variable, then save it as a custom parameter. Finally, you can set the camera’s color space to sRGB or Adobe RGB.

Continuous Shooting Mode and Self-Timer

The Canon Rebel XTi’s Continuous Shooting mode is rated by Canon at three frames per second, for a maximum of 27 frames. Do note, though, that the number of consecutive shots could be limited by CompactFlash space, if your memory card is nearly full. Very complex images with a lot of sharp, fine detail may also compress less and result in lower buffer capacities.

The camera’s Drive setting also accesses a Self-Timer mode, which opens the shutter 10 seconds after the Shutter button is pressed, giving you time to dash around in front of the camera. A Remote Control mode works with the dedicated and wireless remote units as well.

The images above were taken from our standardized test shots. For a
collection of more pictorial photos, see our
Canon EOS 400D Rebel XTi Photo Gallery
.

Not sure which camera to buy? Let your eyes be the ultimate judge!
Visit our Comparometer(tm)
to compare images from the Canon EOS 400D Rebel XTi with those from other
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Canon Rebel XTi Performance

Canon Rebel XTi Imaging Characteristics

Imaging and file quality are ultimately what’s most important in a digital camera, and the Canon Rebel XTi definitely delivers the goods in this area. As you’ll see below, Canon has taken a slightly different path in noise control with the Rebel XTi than Nikon did in the competing D80. The two cameras are surprisingly similar in their high-ISO abilities, but Canon has chosen to preserve a bit more subtle subject detail, at the cost of higher noise, while Nikon has gone the other direction, and given up some subject detail in areas of subtle contrast, but has achieved lower noise levels in the process.

For readers considering an upgrade from the original Digital Rebel, the Rebel XTi represents a very noticeable boost in resolution and overall image quality. If you’re thinking of upgrading from a Rebel XT though, the step up from 8 to 10 megapixels may not be enough to justify the move on the basis of resolution alone. (Think about it: Horizontally, the XT had 3,456 pixels, the XTi has 3,888. That’s a linear increase of only 12.5%. Moving up from the original Rebel’s 3,072 horizontal pixels though, the XTi represents a 26.6% increase, a more noticeable improvement.)

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 claims that high-ISO performance will be very much on par with that of the Rebel XT and EOS-30D, and our tests bear that out. 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 expected net result is that the Rebel XTi’s pixels will have about the same light-gathering ability as the larger ones in the XT’s sensor, despite their smaller physical dimension. We’ll obviously have to wait until we can get our hands on a production sample to test, but if Canon has succeeded, the Rebel XTi’s ISO 1600 performance should be every bit as good as that of the XT. This is encouraging: 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.

There’s no question, the Canon Digital Rebel XTi delivers impressive resolution and image quality. Here’s a look at the details:

Resolution & Detail

Resolution
High resolution, 1,600~1,800 lines of strong detail.

Strong detail to 1,800 lines horizontal	Strong detail to 1,600 lines vertical

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,800 lines per picture height horizontally, though to only about 1,600 vertically. (The individual target lines are still resolved along the vertical axis at 1,700 lines or higher, but some significant artifacts can be seen around 1,650, so we felt that 1,600 was more representative the true resolution there.) Extinction didn’t occur until past the 2,000 line point. Use these numbers to compare with other cameras of similar resolution, or use them to see just what higher resolution can mean in terms of potential detail. Beware that while you might be able to make out what looks like distinct lines at numbers higher than those we’ve mentioned here, the camera is just doing its best to continue interpreting the lines. So the lines you see at 2,000 and higher are really only artifacts generated by the camera’s imaging system.

See full set of test images with explanations
See thumbnails of all test and gallery images

Sharpness & Detail
Sharp images with great detail definition. Minor edge enhancement, and minor noise suppression as well.

Great definition of high-contrast elements, with only slight edge enhancement visible. (This image takes post-capture sharpening very well.)	Subtle detail: Hair Noise suppression tends to blur detail in areas of subtle contrast, as in the darkest parts of Marti’s hair here, but the XTi does manage to preserve subtle detail better than the majority of cameras we test.

The Canon Rebel XTi captures nice, sharp images, with very good detail definition. Some very slight edge enhancement artifacts are visible on high-contrast subjects, such as the crop above left, though results are still very good. (Edge enhancement creates the illusion of sharpness by enhancing color and tonal differences right at the edge of a rapid transition in color or tone.)

Noise-suppression systems in digital cameras tend to flatten-out detail in areas of subtle contrast. The effects can often be seen in shots of human hair, where the individual strands are lost and an almost “watercolor” look appears. The crop above right shows some very minor detail loss to noise suppression, but detail remains fairly strong in the darkest shadows, with individual strands of hair still visible. Overall, the Canon Rebel XTi does a much better than average job of holding onto subtle detail, while reducing image noise.

Color

Saturation & Hue Accuracy
Excellent overall color, with generally pleasing hue accuracy and saturation. Some oversaturation in strong reds, but results are still good.

In the diagram above, the squares show the original color, and the circles show the color that the camera captured. More saturated colors are located toward the periphery of the graph. Hue changes as you travel around the center. Thus, hue-accurate, highly saturated colors appear as lines radiating from the center.

Most consumer digital cameras produce color that’s more highly saturated (more intense) than found in the original subjects. This is simply because most people like their color a bit brighter than life. The Canon EOS Digital Rebel XTi is guilty of pushing the strong reds somewhat, and strong blues slightly, but overall saturation is quite appealing. Where oversaturation is most problematic is on Caucasian skin tones, as it’s very easy for these “memory colors” to be seen as too bright, too pink, too yellow, etc. Skin tones tended to be just slightly warm with the Rebel XTi, depending on the white balance setting, but again, results are natural and pleasing.

The other important part of color rendition is hue accuracy. Hue is “what color” the color is. The Rebel XTi did move cyan a bit toward blue and red just slightly toward orange, but overall hue accuracy is among the best we’ve seen to date.

See full set of test images with explanations See thumbnails of all test and gallery images

Sensor

Exposure and White Balance

Indoors, incandescent lighting
Good color with the Manual white balance setting, but very warm results with the other options. Average positive exposure compensation required.

Auto White Balance +1.0 EV	Incandescent WB +1.0 EV
	Â
Manual White Balance +1.0 EV	Â

Color balance indoors under incandescent lighting was very warm with both the Auto and Incandescent white balance settings, but the Manual option produced more accurate results. (Why can’t manufacturers seem to design their cameras to handle household incandescent lighting better?) The Canon Rebel XTi required an average amount of positive exposure compensation here, at +1.0 EV. Overall color with the Manual white balance setting looks good, though the blue flowers are quite dark and purplish, and the greens are a bit dark as well. (Many digital cameras have trouble with the blue flowers in this shot.) Our test lighting for this shot is a mixture of 60 and 100 watt household incandescent bulbs, a pretty yellow light source, but a very common one in typical home settings here in the U.S.

Outdoors, daylight
Better than average exposure accuracy, though a low contrast adjustment needed to handle harsh lighting. Good overall color, if slightly dark.

Manual White Balance, +0.7 EV, Lower Contrast	Auto White Balance, Auto Exposure, Default Contrast

Outdoors, the Canon EOS Digital Rebel XTi’s default contrast setting resulted in somewhat high contrast under harsh lighting, with dark shadows and hot highlights. However, the lower contrast adjustments (available via the Picture Style submenu off Record Menu 2) did a good job of toning down the image, preserving detail in both shadows and highlights without producing a muddy exposure. The portrait above left was taken with the camera’s next to lowest contrast setting, which produced good-looking results, and excellent highlight detail. Overall color is natural and pleasing outdoors, if slightly dark. The camera typically required less than the average amount of positive exposure compensation. Overall, very nice results.

See full set of test images with explanations
See thumbnails of all test and gallery images

ISO & Noise Performance
Very low image noise, with relatively low noise even at the highest sensitivity setting.

ISO 100	ISO 200	ISO 400
		Â
ISO 800	ISO 1,600	Â

The Canon EOS Digital Rebel XTi produced very low image noise overall. At ISO 800, noise was a little high, though without very strong blurring in the finer details. Even at ISO 1,600, noise is lower than average, and fine detail is still pretty good. As noted above, the Canon Rebel XTi does a much better job than average in suppressing image noise without losing fine/subtle subject detail.

ISO 1600 Comparison
Against its primary competitor,the Nikon D80, the Canon XTi shows more chroma noise, but better preservation of subtle detail.

While it sells at a higher price, with a more capable lens, the obvious competition for the Canon Digital Rebel XTi is Nikon’s D80. In the past, Canon’s noise-suppression technology has generally been superior to that of other manufacturers, but with the D80, Nikon seems to have pulled even. Given the rivalry between these two particular cameras, we’ll look at two sets of crops from them both, at ISO 1,600.

In the first set of crops, we’ll look at swatches from the Macbeth ColorChecker target, as an example of how each performs in areas with flat tints. We’ll show both the RGB image, and the individual red, green, and blue color channels, so you can see what’s going on in the individual color channels.

ISO 1600 Flat-Tint Noise Comparison
Nikon D80 (“Normal” high-ISO NR)	Canon Rebel XTi
(click for full D80 file) — RGB — (click for full XTi file)
Red Channel
Green Channel
Blue Channel

The pixel-peeping crops above tend to favor the D80, both due to their enlargement, and because they’re showing a relatively limited area. In the full images, the D80 shows some blotchiness when you look at larger areas (for instance, the dark border around the MacBeth chart) that isn’t evident in the Canon Rebel XTi’s image. As noted in the Imatest Results section of the D80 review, this corresponds to a spike in the very lowest frequencies on the D80’s noise spectrum, compared with a notch in the same area on the Rebel XTi’s spectrum plot. (We speculate that this very low-frequency blotchiness is something that Canon’s active-pixel CMOS technology is particularly good at dealing with.)

In the next set of crops, we’ll look at some samples from our Still Life target, where the tone-on-tone coloring of the fabric swatches reveals much about the inner details of how cameras make the trade-off between subject detail and sensor noise.

ISO 1600 Tone-on-Tone Noise/Detail Comparison
Nikon D80 (“Normal” high-ISO NR)	Canon Rebel XTi
(click for full D80 file) —- (click for full XTi file)

In the first set of crops, we saw that the D80 won handily in terms of noise present in areas of flat tint. In the second set of crops, though, we see the price that’s paid to achieve that, namely that fine detail in areas of subtle contrast, and some overall sharpness are lost in the process. In the crops above, we consistently see more fine detail retained by the XTi, albeit at the cost of higher image noise, particularly chroma (color) noise. It’s also interesting to note how the noise processing varies as a function of the part of the color spectrum you’re looking at. This is particularly evident in the D80’s images, which give up detail in reds and yellows far more quickly than in blues and purples. (You can see this effect most clearly in the crop showing the red fabric swatches above.)

As always, it’s important to note that we’re engaged in some pretty deep pixel-peeping here, given that we’re looking at images from 10 megapixel cameras 1:1 on a computer screen. Given typical computer display resolutions of ~75 pixels/inch, this corresponds to peering at printed images roughly 52 x 35 inches(!) in size. Not to totally dismiss the differences noted above though, you can see detail differences in the red fabric swatches even in 8×10 inch prints — But you have to squint and look pretty carefully to make them out.

The bottom line is that we have two slightly different approaches to noise suppression here, one slightly favoring smoothness in flat tints, the other slightly favoring subtle detail. How you feel about either will depend a lot on your personal preferences, both cameras deliver really excellent images at high ISO settings.

Extremes: Sunlit and low light tests
Very high resolution and strong detail. Best results with the lower contrast adjustment, good overall color. Excellent low-light performance, capable of capturing bright images in near darkness.

+0.3 EV	+0.7 EV	+1.0 EV

Sunlight:
Because digital cameras are more like slide film than negative film (in that they tend to have a more limited tonal range), we test them in the harshest situations to see how they handle scenes with bright highlights and dark shadows, as well as what kind of sensitivity they have in low light. The shot above is designed to mimic the very harsh, contrasty effect of direct noonday sunlight, a very tough challenge for most digital cameras. (You can read details of this test here.)

Under the harsh lighting of the test above, the Canon EOS Digital Rebel XTi produced high contrast with washed-out highlights and deep shadows with its default contrast setting. However, the Rebel XTi’s next-to-lowest contrast adjustment (as seen above) produced much more pleasing results, with better midtones, without washing out the colors in the image. The Rebel XTi’s contrast and saturation settings are a bit buried, down in the Picture Style sub-menu, off the main shooting menu, but they’re very effective, and provide a nice range of control, with fine enough steps that you can pick exactly the effect you want. With the lower contrast setting, these images show good detail at both extremes of the tone curve, in both shadows and strong highlights. Exposure is just a little dark at the +0.7 EV compensation setting, but I felt the +1.0 EV image was too bright. (In “real life” of course, be sure to use fill flash in situations like the one shown above; it’s better to shoot in the shade when possible.)

Â	1 fc 11 lux	1/2 fc 5.5 lux	1/4 fc 2.7 lux	1/8 fc 1.3 lux	1/16 fc 0.67 lux	1/16 fc No NR
ISO 100	2.5 sec f3.5	5 sec f3.5	10 sec f3.5	20 sec f3.5	30 sec f3.5	30 sec f3.5
ISO 200	1.3 sec f3.5	2.5 sec f3.5	5 sec f3.5	10 sec f3.5	15 sec f3.5	15 sec f3.5
ISO 400	1/1 sec f3.5	1.3 sec f3.5	2.5 sec f3.5	5 sec f3.5	8 sec f3.5	8 sec f3.5
ISO 800	1/3 sec f3.5	1/1 sec f3.5	1.3 sec f3.5	2.5 sec f3.5	4 sec f3.5	4 sec f3.5
ISO 1600	1/6 sec f3.5	1/3 sec f3.5	1/1 sec f3.5	1.3 sec f3.5	2 sec f3.5	2 sec f3.5

Low light:
The Rebel XTi captured bright images down to the lowest light level we test at, at all ISO settings. This equates to about 1/16 the brightness of average city street lighting at night, so the XTi should be able to take well-exposed photos in any environment you can see well enough to walk around in without blundering into things. Though the images are still fairly bright at the lowest light level, the longer exposure did result in a more pronounced pink color cast. Overall noise was really quite low to begin with, but the camera’s Long Exposure Noise Reduction option (Custom Function 02) did tone down the brightness of visible noise pixels. The camera’s autofocus system was able to focus on the subject down to just below the 1/16 foot-candle light level unassisted, almost in line with its exposure system. (The XTi does have an autofocus-assist light option, but it uses the camera’s flash tube as the illuminator, and so requires the flash system to be engaged for it to work.) Do keep in mind that the very long shutter times necessary here absolutely demand the use of a tripod or other camera support to get sharp photos. (A useful trick is to just prop the camera on a convenient surface, and use its self-timer to release the shutter. This avoids any jiggling from your finger pressing the shutter button, and can work quite well when you don’t have a tripod handy.)

How bright is a foot-candle? The one foot-candle light level that this test begins at roughly corresponds to the brightness of typical city street-lighting at night. Cameras performing well at that should be able to snap good-looking photos of street-lit scenes.

NOTE: This low light test is conducted with a stationary subject, and the camera mounted on a sturdy tripod. Most digital cameras will fail miserably when faced with a moving subject in dim
lighting. (For example, a child’s ballet recital or a holiday pageant in a gymnasium.) Digital SLRs like the Canon XTi do much better than point & shoots, but you still shouldn’t expect a quick autofocus lock with moving subjects.

Output Quality

Print Quality
Excellent print quality, great color, excellent 13×19 inch prints. ISO 1,600 images are surprisingly clean and sharp at 8×10 inches: Most users would probably find high-ISO shots acceptable even at 11×14.

Testing hundreds of digital cameras, we’ve found that you can only tell just so much about a camera’s image quality by viewing its images on-screen. Ultimately, there’s no substitute for printing a lot of images and examining them closely. For this reason, we routinely print sample images from the cameras we test on our Canon i9900 studio printer, and on the Canon iP5200 here in the office. (See the Canon i9900 review for details on that model.)

The Canon Digital Rebel XTi didn’t fail to impress us when it came time to examine its printed output. JPEGs straight from the camera made good-looking 13×19 inch prints, and delivered loads of crisp detail with a little sharpening in Photoshop. Working from RAW files, you could probably print a good bit larger than 13×19 with little trouble or obvious softness.

As we’ve come to expect from DSLRs built around Canon’s CMOS sensor technology, the Rebel XTi performed very well at high ISO settings. Shots captured at ISO 1,600 looked great printed as large as 8×10 inches, and most users would likely be satisfied with prints as large as 11×14 inches at that ISO setting. We did notice some chroma (color) noise in areas of flat tint, but it wasn’t too bad at print sizes of 8×10 inches or below. As noted elsewhere in this review, when compared against its primary competitor the Nikon D80, the XTi tends to have a bit more chroma noise than the D80, but conversely does a better job of holding onto subject detail in areas of subtle contrast, or tone-on-tone color variations.

Noise is an awfully subjective issue though: What you think of the XTi’s ISO 1,600 shots will depend a lot on your tolerance for image noise, and the size you intend to print at. We ourselves tend to print at 8×10 or 8.5×11 inches, frame the results, and hang them on a wall or park them on a table. With that set of givens, we’d feel perfectly comfortable shooting with the XTi at ISO 1,600 as a matter of course. We don’t say that often.

The XTi’s color was also beautiful, as printed on the i9900. Strong reds did tend to saturate somewhat, but not as badly as on many cameras, and the rest of the spectrum was rendered very nicely. Skin tones were very natural, and the whole effect was bright, but very believable and appealing. Bottom line, the XTi delivered excellent prints.

Canon Rebel XTi Viewfinder

As noted in a few places in this review, the most natural camera to compare to the Canon XTi is the Nikon D80. The D80 sells for a good bit more money than the XTi (as of this writing in November 2006, about $100-200 more, body-only), but it’s the camera that most prospective XTi buyers not already locked into a lens system will be evaluating it against. The viewfinder is one area in which the D80 enjoys a considerable advantage over the XTi, thanks to its combination of prism-based construction and noticeably higher magnification factor. In simple terms, the D80’s viewfinder is quite visibly larger and brighter. The illustration below shows the difference in apparent viewfinder sizes between the two cameras.

The most visible difference between the two viewfinders is size: Switching back and forth between the D80 and XTi, the XTi’s viewscreen looks much smaller by comparison. While pentaprism viewfinders are brighter than pentamirror ones, the brightness difference is much more subtle. With well-lit subjects, we really didn’t notice much of a difference, but when working under dim lighting, we definitely felt we could see farther into the shadows with the D80 than with the XTi.

We don’t want to make too big a deal out of the differences between the D80 and XTi’s viewfinders. The XTi’s viewfinder is quite adequate. It’s just another factor you should be aware of and may want to consider in choosing an SLR.

As noted in the overview, 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 illustration below shows all the elements in the XTi’s viewfinder. The faint grey lines show the arrangement of the camera’s 35 metering areas, and do not appear in the actual viewfinder display.

Note that, while the nine AF areas are in the same locations as those in the 30D’s viewfinder, 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. We personally find this style of AF marker much more visible than those in the Nikon D80, where the outlines surrounding active AF areas glow a faint red.

Apart from these changes, the viewfinder is essentially the same as that of the previous XT, with identical specifications: 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 (an unusually wide range), and the same Precision Matte focusing screen is used.

Viewfinder

Coverage
Very good frame accuracy with the optical viewfinder.

18mm eq., Optical	55mm eq., Optical

The Rebel XTi’s optical viewfinder showed about 97% frame accuracy at 18mm, and about 94% at 55mm. Both are very good, although as usual, we wonder why manufacturers can’t make SLR viewfinders cover 100% of the frame.

Canon Rebel XTi Flash

The Rebel XTi’s built-in flash has a guide number rating of 43 feet (13 meters) at ISO 100, translating to a range of about 15 feet at ISO 100 with an f/2.8 lens. (Reasonably powerful, but not dramatically so.) The Canon Rebel XTi gives you a great deal of control over flash exposure, allowing you to adjust flash and ambient exposure independently of each other, in one-half or one-third EV increments. This makes it very easy to balance flash and ambient lighting for more natural-looking pictures. The Rebel XTi also uses E-TTL II control for both the built-in and compatible external flashes (according to Canon this includes the older 550EX flash, as well as the newer 580EX; though the 580EX offers even more), a new standard that promises, and seems to deliver better, more balanced exposures. Custom Function 08 turns this mode off and returns to an average metering system. E-TTL II is only available with the built-in flash or when the camera is paired with either the 550EX or the new 580EX flash.

Another nice touch is the Flash Exposure Lock button, which fires the flash under manual control before the actual exposure, to determine the proper exposure setting. This struck me as very handy, akin to the more conventional autoexposure lock function for handling difficult ambient lighting conditions. A Flash Exposure Compensation feature controls the flash exposure +/- 2 stops in 1/2 or 1/3-stop increments.

Several of the more impressive features of the Canon flash system depend on the dedicated 550EX or 580EX speedlight. Among these are true FP (focal plane) flash sync, flash exposure bracketing with external flash units, flash modeling, and E-TTL II exposure control. FP sync requires a flash unit to provide uniform light output for a relatively long period of time, long enough for the focal plane shutter curtain to fully traverse the sensor plane. On the Canon Rebel XTi, this requires a flash duration of 1/200-second. Uniform, long-duration flash pulses like this permit use of shutter speeds as high as the 1/4,000-second maximum that the Canon Rebel XTi is capable of. This can be invaluable when you want to exclude ambient light from the exposure. (FP sync mode is referred to as “high speed” mode on the Canon 550 and 580 flash units.)

Here’s the rundown on Canon Speedlights and their compatibility with the XTi:

You’ll note the references to “E-TTL remote” capabilities in the table above. Canon’s Speedlight system permits TTL flash metering with multiple remote units, and even allows you to set differential power ratios between the slaved units, over a six-stop flash exposure range.

The “Flash Modeling” feature of the 550EX and 580EX speedlights is quite useful. With a F550EX or F580EX connected to the XTi, pressing the camera’s Depth of Field Preview button causes the speedlight to fire at 70 flashes per second for about one second. This creates the illusion of a constant light source for your eyes, letting you preview the lighting on your subject when the flash fires. VERY handy, and likely to save lots of shoot/check/reshoot time!

As alluded to above, the “X-sync” speed of the Canon Rebel XTi is 1/200-second. (This is the maximum shutter speed that can be used on the Rebel XTi when working with a non-dedicated, FP-capable speedlight.) When used with higher-powered studio strobe systems, Canon recommends a maximum shutter speed of 1/60-second or slower, to accommodate the time/intensity profile of such units.

A final benefit of the dedicated Canon speedlights is that they carry powerful autofocus assist illuminators that can extend the range of the built-in AF assist light of the Rebel XTi. For example, the AF assist beam on the 550EX is rated as good to about 50 feet, versus the roughly 13 feet of the pulse flash on the Canon Rebel XTi itself. (As mentioned above though, note that the ST-E2 wireless sync transmitter can also be used for AF assist during non-flash photography, a handy trick.)

Canon’s E-TTL II flash exposure system also works with certain lenses to include object distance data into its calculations so it can adjust the flash power accordingly. A preflash is fired and the resulting readings compared to the ambient light reading for each of the camera’s 35 metering zones from just prior to the flash, to identify and compensate for specular objects (that is, very reflective surfaces). In instances where most cameras would underexpose an image because of a reflective object in the frame, the Rebel XTi will ignore the brighter areas and expose the subject correctly in most instances. This is designed to help shooters like event photographers–especially wedding photographers, whose cameras are constantly forced to balance a bright white dress against all manner of reflective materials on the clothing of others, in addition to the usually black tuxedos of the groomsmen.

Flash

Coverage and Range
Average flash exposure compensation required. Pretty good range though.

18mm equivalent	55mm equivalent
Normal Flash +1.0 EV	Slow-Sync Flash +1.3 EV

Flash coverage was very uneven at wide angle and telephoto, with strong falloff in the corners and edges of the frame. Indoors, under incandescent background lighting, the Canon Rebel XTi’s flash underexposed our subject quite a bit at its default setting, requiring a +1.0 EV exposure compensation adjustment to get bright results. The camera’s Slow-Sync flash mode required a little more positive compensation at +1.3 EV, though overall coverage is more even. However, the longer shutter speed results in a stronger orange cast from the background lighting.

Flash Range: Wide Angle
6 ft	7 ft	8 ft	9 ft	10 ft	11 ft
0.5 sec f3.6 ISO 100	0.5 sec f3.6 ISO 100	0.5 sec f3.6 ISO 100	0.5 sec f3.6 ISO 100	0.5 sec f3.6 ISO 100	0.5 sec f3.6 ISO 100
12 ft	13 ft	14 ft	15 ft	16 ft
0.5 sec f3.6 ISO 100	0.5 sec f3.6 ISO 100	0.5 sec f3.6 ISO 100	0.5 sec f3.6 ISO 100	0.5 sec f3.6 ISO 100

Flash Range: Telephoto
6 ft	7 ft	8 ft	9 ft	10 ft	11 ft
0.5 sec f5.7 ISO 100	0.5 sec f5.7 ISO 100	0.5 sec f5.7 ISO 100	0.5 sec f5.7 ISO 100	0.5 sec f5.7 ISO 100	0.5 sec f5.7 ISO 100
12 ft	13 ft	14 ft	15 ft	16 ft
0.5 sec f5.7 ISO 100	0.5 sec f5.7 ISO 100	0.5 sec f5.7 ISO 100	0.5 sec f5.7 ISO 100	0.5 sec f5.7 ISO 100

The Canon EOS Digital Rebel XTi’s built-in flash was bright and powerful, with good intensity all the way to 16 feet at ISO 100, with the lens at 18mm. At 55mm, intensity remained bright to about 8 feet. We’re not sure of the reason, but the 16 foot distance is beyond the rated range of the flash, yet still resulted in a good exposure. The falloff at telephoto for distances greater than ~8 feet does agree with Canon’s own rating, however.

Manufacturer-Specified Flash Range
Wide Angle	Telephoto
12.3 feet ISO 100	7.7 feet ISO 100

Our standard test method for flash range uses a fixed setting of ISO 100, to provide a fair basis of comparison between cameras. We also capture two shots using the manufacturer-specified camera settings, at the range the company claims for the camera, to assess the validity of the specific claims. In the shots above, the Rebel XTi performs as Canon says it will, producing good exposures at the rated distances.

Canon Digital Rebel XTi Imatest Results

We routinely Norman Koren’s excellent “Imatest” analysis program for quantitative, thoroughly objective analysis of digicam test images. I highly recommend it to our technically-oriented readers, as it’s far and away the best, most comprehensive analysis program I’ve found to date.

My comments below are just brief observations of what we see in the Imatest results. A full discussion of all the data Imatest produces is really beyond the scope of this review: Visit the Imatest web site for a full discussion of what the program measures, how it performs its computations, and how to interpret its output.

Here are some of the results produced by Imatest for the Canon Rebel XTi:

The Canon XTi showed good color accuracy overall, but went a bit overboard with strong reds. This is a fairly common response with this target (the MacBeth ColorChecker), and the XTI’s response is fairly typical for consumer DSLRs, more highly saturated than that of pro models. Hue accuracy is excellent, with minor shifts in a number of colors, rather than large shifts in any one area. The largest shift was in yellow-orange, which moved toward yellow a fair bit. Average saturation was 109.7% (oversaturated by 9.7%, largely in the reds, but somewhat in the blues as well), average “delta-E” color error was just 4.7 after correction for saturation. All in all, an excellent, nicely-balanced color response for a consumer SLR, one of the best we’ve seen to date. (The Canon Rebel XTi beats its main competitor the Nikon D80 slightly in hue accuracy, and is a bit less saturated in strong reds and blues.)

This image shows how the Canon Rebel XTi actually rendered the colors of the Macbeth chart, compared to a numerically ideal treatment. (Apologies for the tilt, the Macbeth chart on our Multi target had slipped slightly in these shots.) In each color swatch, the outer perimeter shows the color as actually captured by the camera, the inner square shows the color after correcting for the luminance of the photographed chart (as determined by a 2nd-order curve fit to the values of the gray swatches), and the small rectangle inside the inner square shows what the color should actually be, based on perfect rendering in the sRGB color space. This image shows the excellent hue accuracy, as well as a gamma curve that results in an overexposure of highly saturated swatches.

As always, there’s a lot in this particular graph, a lot more than we have room to go into here. In comparing these graphs with those from other competing cameras, I’ve found that the Noise Spectrum graph at lower right is the most important. Cameras that manage to shift their noise spectrum to higher frequencies have much finer-grained noise structures, making their noise less visually objectionable. In the graph above, this would show up as a noise spectrum curve that remained higher on the right side, representing higher noise frequencies. The champion at this was the Canon EOS-1Ds Mark II, which produced remarkably fine-grained image noise, even at very high ISOs. Bottom line, the Canon XTi’s noise levels are low at low ISO, and the frequency spectrum somewhat favors high frequencies, but there’s a spike at very low frequencies that would normally translate into a blotchy appearance, were the overall level of the noise high enough to be seen (it isn’t).

Here’s the same set of noise data at ISO 1600. Here, more of the mass of the Noise Spectrum graph is shifted toward the left-hand, lower-frequency side than it was at ISO 100, coarsening the “grain” of the image noise patterns. Not bad, but there’s quite a lot of noise energy present in the left-hand side of the graph, from 0.0 to 0.2 cycles/pixel, rather than in the range from 0.2 to 0.5 cycles/pixel. This is visible in its images, where the XTi’s luminance noise is generally higher than that of the Nikon D80. (There is very interesting and subtle difference in the noise spectra of the two cameras though: The D80’s has a spike leading right up to zero frequency, whereas the XTi has a dip there. This shows up in high ISO shots as a slightly “splotchy” look to large, uniform dark areas in the D80’s images that isn’t shown by the XTi’s. (You can see this in the black surround on the MacBeth chart in our Multi Target shots.

This chart compares the Canon XTi’s noise performance over a range of ISOs against that of other cameras. While I continue to show noise plots of this sort because readers ask for them, I each time point out that the noise magnitude is only a small part of the story, the grain pattern being much more important. There’s also the matter of how much subtle subject detail is traded away in pursuit of low noise figures. In the case of the Canon Rebel XTi, while it shows slightly better than average noise levels at higher ISO, it does let through quite a bit more noise than does the Nikon D80 under similar conditions. The upside to this is that the XTi does a much better job of holding onto fine subject detail in areas of subtle contrast. (For instance, check out the red fabric swatch with the black leaves in our Still Life test shot, and compare the detail there with that from the Nikon D80.)

Dynamic Range Analysis

A key parameter in a digital camera is its Dynamic Range, the range of brightness that can be faithfully recorded. At the upper end of the tonal scale, dynamic range is dictated by the point at which the RGB data “saturates” at values of 255, 255, 255. At the lower end of the tonal scale, dynamic range is determined by the point at which there ceases to be any useful difference between adjacent tonal steps. Note the use of the qualifier “useful” in there: While it’s tempting to evaluate dynamic range as the maximum number of tonal steps that can be discerned at all, that measure of dynamic range has very little relevance to real-world photography. What we care about as photographers is how much detail we can pull out of the shadows before image noise becomes too objectionable. This, of course, is a very subjective matter, and will vary with the application and even the subject matter in question. (Noise will be much more visible in subjects with large areas of flat tints and subtle shading than it would in subjects with strong, highly contrasting surface texture.)

What makes most sense then, is to specify useful dynamic range in terms of the point at which image noise reaches some agreed-upon threshold. To this end, Imatest computes a number of different dynamic range measurements, based on a variety of image noise thresholds. The noise thresholds are specified in terms of f-stops of equivalent luminance variation in the final image file, and dynamic range is computed for noise thresholds of 1.0 (low image quality), 0.5 (medium image quality), 0.25 (medium-high image quality) and 0.1 (high image quality). For most photographers and most applications, the noise thresholds of 0.5 and 0.25 f-stops are probably the most relevant to the production of acceptable-quality finished images, but many noise-sensitive shooters will insist on the 0.1 f-stop limit for their most critical work.

The image below shows the test results from Imatest for an in-camera JPEG file from the Canon XTi with a nominally-exposed density step target (Stouffer 4110), with the Canon Rebel XTi’s contrast setting at its default position.

These are decent if not exceptional numbers for an in-camera JPEG, but the dynamic range number at “high” quality itself (7.04) isn’t the most important thing to look at here. A dynamic range of 7.04 f-stops at high image quality is within a half a stop of most of the XTi’s competition, not enough difference to be a significant issue. (Yes, a half a stop more dynamic range would be nice, but that’s not the main thing that affects what a photographer will perceive as the XTi’s dynamic range here.)

More significant than the absolute dynamic range is the shape of the density curve, and how smoothly it transitions from highlight to midtone to shadow. The XTi has a very smooth curve at the highlight (right) end of its curve, and a smooth but slightly more abrupt curve at the shadow (left) end. This tells us that the XTi does a good job of holding both highlight and shadow detail, but slightly better at the highlight end of the tonal scale.

That’s the story with JPEG files created in the camera, how about in an external RAW converter, such as Adobe Camera Raw (ACR)?

Using its automatic settings (which in my experience has generally worked best for dynamic range tests like this), ACR managed to extract a very healthy 8 tenths of a stop more dynamic range from the CR2 RAW file at the highest quality level, while still maintaining very good shape in the tone curve. This boost in dynamic range is enough to put the XTi’s performance under ACR close to the top of the pack, regardless of camera selling price.

Dynamic Range, the bottom line:

So what conclusions can we draw about the Canon Rebel XTi’s dynamic range? I think two things: First, that the XTi’s internal JPEG output produces a nicely shaped tone curve, with good detail available at both ends of the curve. Beyond that though, the XTi’s CR2 RAW files do contain a modest amount of additional information that the right RAW converter can extract.

To get some perspective, here’s a summary of the Canon Rebel XTi’s dynamic range performance, and how it compares to other digital SLRs that we also have Imatest dynamic range data for. (Results are arranged in order of decreasing dynamic range at the “High” quality level.):

Standard Observations:
The results shown in the table are interesting. One of the first things that struck me when I initially looked at test data for a wide range of d-SLRs, was that here again, purely analytical measurements don’t necessarily correlate all that well with actual photographic experience. There’s no question that the Fuji S3 Pro deserves its place atop the list, as its unique “SR” technology does indeed deliver a very obvious improvement in tonal range in the highlight portion of the tonal scale. I was surprised to see the analytical results place the original Olympus EVOLT as highly as they did, given that our sense of that camera’s images was that they were in fact noisier than those of many other d-SLRs that we looked at. In the other direction, I was quite surprised to see the Nikon D2x place as low on the listings as it did, given that we found that camera’s shadow detail to be little short of amazing.

One thing that’s going on here though, is that we tested each camera at its lowest ISO setting, which should produce best-case noise levels. This is in fact what many photographers will be most interested in, but it does perhaps place some of the Nikons at a disadvantage, as their lowest ISO setting is 200, as compared to the ISO 100 settings available on most other models.

Canon Rebel XTi Specifics:
Regardless of the positions of the other cameras though, the Canon XTi does appear to have a good dynamic range, coupled with a well-proportioned tone curve. And working with its RAW files via Adobe Camera Raw (we used version 3.6 in these tests), it delivers really excellent dynamic range by any standard.

As I always say though, at the end of the day, I think you have to take the figures here with a grain of salt, and look at actual images with your own eyes to see what you make of each camera’s tonal range and noise levels. We’ll continue performing these dynamic range tests on the digital SLRs that we review, but (just as with the laboratory resolution target results), we suggest that you not rely on them exclusively for making your purchase decisions.

Resolution Chart Test Results

The chart above shows consolidated results from spatial frequency response measurements in both the horizontal and vertical axes. The “MTF 50” numbers tend to correlate best with visual perceptions of sharpness, so those are what I focus on here. The uncorrected resolution figures are 1611 line widths per picture height horizontally and 1612 lw/ph vertically. Correcting to a “standardized” sharpening with a one-pixel radius increases these numbers slightly, to an average of 1757 LW/PH. It appears that Canon has struck a very good balance between the XTi’s anti-aliasing filter (which blurs the image somewhat, to avoid digitization artifacts) and its in-camera image sharpening. The XTi’s images show good sharpness right from the camera for normal-sized prints (up to about 13×19 inches), but as always, you can do better with finely-tuned sharpening in Photoshop or another image-processing application, particularly if you’re going to be printing at very large sizes.

To see what’s going on, refer to the plots below, which show the actual edge profiles for both horizontal and vertical edges, in both their original and corrected forms. Bottom line, the XTi captures really excellent detail, really making the most of its 10.1 megapixel sensor. You can’t sharpen its camera-created JPEGs quite as much as those from some of Canon’s professional DSLRs, but they’re much crisper looking straight from the camera, as is appropriate for a DSLR aimed at the consumer market. That said, enthusiast shooters will be able to extract a lot of fine detail with a little playing around using Photoshop’s unsharp masking operator or other image-sharpening application.

Canon Rebel XTi Modes and Menus

The mode dial on the right side of the Canon Rebel XTi’s top panel lets you select various exposure modes, with the same range of options presented as on the preceding Rebel XT. Canon divides the dial into “Basic” and “Creative” zones, the Basic range encompassing the Full Auto setting and the six scene modes in what Canon refers to as the “Image” zone. The Creative zone includes settings for programmed exposure, shutter priority, aperture priority, full manual control, and the Automatic Depth of Field mode.

Here’s a description of each of the shooting modes:

Flash Off Mode: The first mode in the Image Zone, Flash Off mode disables both the internal flash head and any external flash unit connected. Focus is set to AI Focus mode, drive mode is set to Single, and metering is set to Evaluative. The camera controls ISO and Auto white balance as well.

Night Portrait Mode: This mode is for taking pictures of people at sunset or at night, letting the flash illuminate the subject, while the longer exposure provides a brighter view of the surroundings. The autofocus mode is automatically set to One Shot. Drive mode is set to Single Shot, and metering mode is set to Evaluative. Since slower shutter speeds will be used, a tripod is recommended to prevent movement from the camera. The built-in flash is automatically enabled and synched with the slower shutter speed, so subjects will need to remain still for a few moments after the flash fires to avoid ghost-like after-images. ISO is automatically adjusted by the camera. (For night exposures without the flash, Canon recommends shooting in Landscape mode.)

Sports Mode: This mode uses a faster shutter speed to capture fast-moving subjects. The autofocus mode is automatically set to AI Servo. Drive mode is set to Continuous Shooting, ISO is set to Auto, and metering mode is set to Evaluative. The onboard flash isn’t available in this mode (since it can’t cycle fast enough to keep up with the continuous exposure mode).

Close-up Mode (Macro Mode): Turning the Mode dial to the macro flower symbol sets the camera for capturing smaller subjects such as flowers, jewelry, and other small details. The autofocus mode is automatically adjusted to One Shot, the drive mode is set to Single Shot, and the metering mode is set to Evaluative. ISO is set to Auto. Close-up mode takes advantage of the current lens’ minimum focal distance. However, an EOS dedicated macro lens and the Macro Ring Lite MR-14EX are recommended for better close-up photography. – In our own testing, the Rebel XT’s flash throttled down quite well for close-up shots, but the position of the flash head produced somewhat uneven lighting. Also, note that unlike the macro mode on most consumer digital cameras, Macro mode on the XTi has no effect on lens focusing range, as that parameter is entirely determined by the lens being used.

Landscape Mode: Landscape mode combines slower shutter speeds with smaller aperture settings to increase the depth of field when shooting broad vistas and sweeping landscapes. This mode is also good for night scenes without people in them. The built-in flash is automatically disabled, even if it’s already raised. Because this mode uses slower shutter speeds, a tripod may be needed in less-bright lighting conditions. Metering is again set to Evaluative and ISO to Auto.

Portrait Mode: This mode uses a large aperture setting to decrease the depth of field, which blurs the background to emphasize the subject. ISO is set to Auto, metering to Evaluative, and AF mode to One Shot. Drive mode is set to Continuous Shooting.

Full Automatic Mode: The final mode in the Basic Zone, Full Automatic is indicated on the Mode dial by a green rectangular outline. In this mode, the camera makes all exposure decisions with the exception of image quality. Autofocus mode is set to AI Focus. (AI Focus evaluates subject movement, automatically sets either one-shot AF or AI Servo AF automatically.) Drive mode is set to Single Shot, ISO is set to Auto, and the metering mode is set to Evaluative.

Program AE: This is the first mode in the Creative Zone of the Mode Dial. Program AE works similarly to the Full Automatic exposure mode, but allows more control over the exposure variables. Aperture and shutter speed are automatically selected by the camera, but you can bias the exposure to larger or smaller apertures by turning the Main dial, which will change the combination of aperture and shutter speed so as to maintain the same exposure value, but with a different combination of aperture/shutter speed. (Personally, I find this sort of vari-program mode more useful than the usual shutter- or aperture-priority modes when I’m wanting to adjust the aperture or shutter speed to control depth of field or subject motion blur. The camera won’t let you select a combination of exposure parameters that doesn’t work, but you retain all the flexibility of shutter- or aperture-priority exposure modes.)

Shutter-Priority AE: This mode allows you to manually set the shutter speed anywhere from 1/4,000 to 30 seconds, while the camera chooses the best corresponding aperture setting. You have control over all other exposure variables, including exposure compensation.

Aperture-Priority AE: The opposite of Shutter-Priority mode, Aperture-Priority AE allows you to set the lens aperture (with available apertures depending on the lens in use), while the camera selects the most appropriate shutter speed. Again, you have control over all other exposure variables, including exposure compensation.

Manual Exposure: This mode provides the same range of exposure control as the other Creative Zone exposure modes (except for exposure compensation), but lets you control both shutter speed and lens aperture independently. The shutter speed range is extended to include a Bulb setting, allowing long exposures for as long as you hold the Shutter button down. (The rear display reports the elapsed time, from one to 999 seconds, as the exposure progresses.) A display in the viewfinder reports whether the camera thinks your settings will result in under, over, or correctly exposed photos.

Automatic Depth of Field AE: This is the final mode in the Creative Zone, and is meant for taking pictures of large groups of people, landscapes with foreground detail, or any subject with elements of interest at varying distances from the camera. This mode puts the camera in control of both the shutter speed and aperture values, but you can adjust the other exposure variables. (This mode cannot be used if the lens focus mode is set to manual.) When shooting in Automatic Depth of Field AE, the camera sets both the lens aperture and focus distance to achieve a sharp focus over a wide depth of field. It uses the autofocus system to measure the distance to the subjects covered by each of the nine autofocus zones, and then attempts to set the focusing distance and lens aperture so as to render all subject areas in sharp focus. (This is a really useful mode, I wish other manufacturers would steal a page from Canon’s playbook on this one.)

Playback Mode: This mode is entered by pressing the Play button on the back panel. Playback mode lets you erase images, protect them, or set them up for printing on DPOF compatible devices. You can also view images in an index display, enlarge images to 10x, view a slide show of all captured images, or rotate an image. The Info button activates an information display, which reports the exposure settings for the image and graphs the exposure values on a small histogram.

Canon Rebel XTi Menu Layout

The Rebel XTi’s menus are quite similar to those of the XT, but there are a few changes. Since many readers may already be familiar with the XT’s menu system, we’ll take a quick look at the primary differences.

Shooting Menu 1
Rebel XTi	Rebel XT
Entries for AF mode, Metering mode, ISO speed have been dropped from the XTi, since these all appear on the main shooting screen anyway.

Shooting Menu 2
Rebel XTi	Rebel XT
Flash exposure compensation now has a scale displayed, white balance option has been moved to main shooting screen, Picture Style replaces Parameters, and Dust Delete Data has been added.

Playback Menu
Rebel XTi	Rebel XT
Transfer order has been added, to support automatic transfers to a host computer. Histogram option added, to select between Brightness and RGB histogram displays.

Setup Menu 1
Rebel XTi	Rebel XT
Auto power-off has 30 second option added, which is now the default, to help save power. Options added for Auto Rotate. (You can now choose whether to auto-rotate played-back images both on camera and on the computer, or on the computer only.) LCD auto off option has been added to control LCD illumination via the face sensor in the viewfinder eyepiece. The shoot w/o card option has been removed, to make room.

Setup Menu 2
Rebel XTi	Rebel XT
The communication setting option has been removed to make room for option to control built-in sensor cleaning.

Custom Function Menu
Rebel XTi	Rebel XT
Two new custom functions added: Magnified View: You can now choose to have the camera’s instant review display a magnified image, or have manification apply to playback-mode displays only. LCD display when power ON: You can choose to turn off the main shooting display screen by pressing the DISP button. This custom function setting lets you choose whether or not the camera remembers the prior setting when the camera is turned off and back on again.

Canon Rebel XTi Menu Details

Record Menu 1:

Record Menu 2:

Playback Menu:

Setup 1:

Setup 2:

Custom Functions Sub-Menu:

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.

Canon Rebel XTi Controls

Control Enumeration, Top Panel Controls

Power Switch: Jutting out to the right from underneath the Mode dial on top of the camera, this switch turns the camera on or off.

Mode Dial: Positioned on the right side of the camera’s top panel, this dial sets the exposure mode. Exposure modes are divided into three zones: Image, Basic, and Creative. The Image Zone encompasses the Flash Off, Night Portrait, Sports, Close-Up (macro), Landscape, and Portrait exposure modes (what most companies call “Scene” modes), while the Basic zone includes all of the same plus the Full Automatic mode. Finally, the Creative Zone refers to the Program AE, Shutter Speed Priority AE, Aperture Priority AE, Manual, and Auto Depth of Field Priority AE exposure modes.

Main Dial: Resting on top of the camera on the right side (as viewed from the back), this ribbed wheel adjusts some of the camera’s basic settings. In Aperture-Priority and Shutter-Priority modes, this dial sets the lens aperture or shutter speed. In Manual mode, the dial sets the shutter speed, but switches to controlling the aperture when the +/- button on the back of the camera is pressed. In Program AE mode, turning this dial selects between a range of equivalent exposure settings. When turned while pressing a control button (such as the Drive Mode or Exposure Compensation buttons), this dial adjusts the selected setting.

Shutter Button: Located on top of the right hand grip in front
of the Main dial, this button fires the shutter when fully pressed, and sets
focus and exposure when halfway pressed in all but Manual exposure mode. (In
Manual exposure mode, it causes the exposure readout to show how much over-
or under-exposed the camera thinks the photo would be, based on the aperture
and shutter speed settings you’ve chosen.)

Control Enumeration, Front Controls

Lens Release Button: Located on the front of the camera, this rectangular button located just to the right of the lens mount unlocks the lens from the mount when pressed. The lens can then be removed by rotating it about 45 degrees to disengage the bayonet mounting flanges.

Control Enumeration, Left Side Controls

Flash Button: Located on the left side of the prism housing, above the lens release button and just below the pop-up flash compartment, this button releases the pop-up flash into its operating position when the camera is on. (The pop-up flash is electronically activated, so it cannot be raised when the camera is turned off.)

Depth of Field Preview Button: Positioned on the side of the
lens mount housing, just beneath the lens release button, this button lets you
preview the depth of field by stopping down the lens aperture to the current
setting in any of the Creative Zone exposure modes. (Like most modern SLRs,
the Canon Digital Rebel XTi normally focuses and meters with the lens wide open,
stopping down to the selected aperture just as the picture is being taken.)

Control Enumeration, Back Panel Controls

Diopter Adjustment Dial: Located outside the top right corner
of the viewfinder eyepiece, this dial adjusts the optical viewfinder’s focus
to accommodate eyeglass wearers, across an unusually wide range of -3 to +1
diopter.

AV/Exposure Compensation Button: Next to the top right corner of the
LCD monitor, this button lets you adjust the exposure compensation from -2 to
+2 EV in one-third or one-half-step increments when pressed while turning the
Main dial (whether it uses 1/2 or 1/3 is set in Custom Function 06). In Manual
exposure mode, pressing this button and turning the Main dial adjusts the aperture
setting.

Drive Mode Button: Just below the AV/Exposure Compensation button, this button brings up the options, and you must use either the Main Dial or the left and right arrows to adjust. Options are Single Shooting, Continuous Shooting, and Self-Timer drive modes.

AE / FE / Index/ Reduce Button: In the top right corner of the rear panel, marked with an asterisk, this button locks the exposure until the Shutter button is pressed. (You can customize the locking operation of this button through the Custom Functions menu.) When pressed while the flash is activated, this button locks the flash exposure, signaling the camera to fire a small pre-flash to measure the exposure before locking it. (This decoupling of exposure lock from autofocusing is a very useful “pro” feature seldom seen on lower-end cameras.)

In Playback mode, this button calls up a nine-image index display of the captured images on the memory card. If a captured image has been enlarged, this button “zooms” back out from the enlarged view.

Focus Area Selector/Magnify Button: Just beside the AE / FE button,
this button allows you to choose the focus area manually or automatically in
Program AE, Shutter-Priority AE, Aperture-Priority AE, or Manual Exposure modes.
Pressing the button and rotating the Main dial cycles through an automatic setting,
or your choice of nine manually-selected focus areas. The automatic setting
selects the active focus point(s) based on the position of the subject within
the frame, and its proximity to the nine focusing points (shown as nine small
boxes arranged in a diamond pattern in the viewfinder).

In Playback mode, pressing this button magnifies the captured image from 1.5
to 10x.

Direct Print Button: Just above the top left corner of the LCD display, this button accesses the camera’s Direct Print feature, for printing images directly from the memory card when the camera is connected to a compatible printer. (The Direct Print menu only appears when connected to a PictBridge-compatible printer. When connected to a Canon printer, the print options are considerably expanded.)

Display Button: The first button in a series lining the left
side of the LCD monitor, this button controls the information display on the
LCD monitor in shooting mode, turning it on or off.

In Playback mode, this button cycles through the available display modes from the image only, to limited information, to a thumbnail display with full exposure information, histogram, and blinking highlights.

Menu Button: Below the Display button, this button accesses the XTi’s
LCD-based operating menu in all modes. Pressing the Menu button a second time
cancels the menu display. (This button also backs out of menu changes.)

Jump Button: Directly below the Menu button, this button allows you to jump 10 or 100 frames forward or backward, or by shot date, when viewing images in Playback mode. Once pressed, a jump bar appears in the LCD screen, and jumping is controlled by pressing the right or left arrow keys. You can select the jump length (10, 100, or date) by using the up/down buttons. The Jump button is active only in Playback mode.

Play Button: Next in line beneath the Jump button, this button
puts the camera into Playback mode, regardless of the Mode dial setting. (Pressing
the right and left arrow keys in this mode scrolls through captured images.)
Playback mode can be canceled by hitting the Play button again, or by touching
the Shutter button. (The Rebel XTi is a “shooting priority” camera.
It’s always ready to shoot a picture, regardless of its current mode. Simply
pressing the Shutter button returns it immediately to capture mode.)

Erase Button: The final button in the series lining the left
side of the LCD monitor, this button accesses the Erase menu, which allows you
to erase the current image or all images on the card (except for protected ones).
There is also an option to cancel. The Erase function works in Playback mode
and Quick Review mode only.

Cross Keys (Four-Way Arrow Pad): To the right of the LCD monitor on the camera’s
back panel, this four-button keypad features arrows in each main direction.
As the camera’s main navigational tool, the keypad selects various camera settings
and menu options while in an LCD menu screen.

In Record mode, the up arrow key brings up the ISO menu item, which can be
adjusted by either turning the Main dial or using the up and down arrows. The
down arrow key opens the white balance menu item, which is adjusted in the same
way. In similar fashion, the right arrow controls the AF mode, while the left
arrow adjusts the metering mode.

In Playback mode, the right and left arrow keys scroll through captured images on the memory card. If an image has been enlarged, all four arrow keys pan the view of the enlarged image.

Set Button (see image above): Located in the center of the Four-Way Arrow pad, this button confirms menu selections and camera settings when using the LCD menu system. When pressed on its own, outside of a menu option or control option, the Set button displays the Picture Style menu, with choices for Standard, Portrait, Landscape, Neutral, Faithful, Monochrome, or three User Defined settings.

EOS 400D / Rebel XTi vs Other Canon SLRs

The chart below compares the XTi with other current Canon cameras. What we’ve done below is presented something of a hybrid comparison between these three models. A red cell means that a given camera performs below the other two, a green cell means that it performs better than the other two, and a yellow cell means it falls between the other two. In cases where two cameras share a superior capability, both cells will be colored green.

We also have a table comparing the Canon Rebel XTi with competing models from other manufacturers. This table is a bit wider though, and breaks the page layout in some browsers, so we’re simply providing a link to it here that will open in a separate browser window. See the Canon XTi vs the Competition comparison table for more info.