C WHITE PAPER THE CANON EOS DIGITAL REBEL XT CAMERA: AN EXCEPTIONAL COMBINATION OF DESIGN, PERFORMANCE AND AFFORDABILITY
Table of Contents I OVERVIEW 3 II SUMMARY OF NEW AND IMPROVED FEATURES Design Image Recording Image Processing Enhanced User Controls 7 7 7 7 8 Flash Performance Connectivity and Compatibility Power Issues Software Package III FEATURE DISCUSSION New 8 Megapixel Image Sensor New DIGIC II Imaging Processor 8 9 9 9 10 10 11 Autofocus 12 E-TTL II Autoflash White Balance Controls Processing Parameters Custom Functions Menus Image Display Exposure Controls Power Management 13 14 15 16 16 17 18 19 20 Re
I. OVERVIEW Canon’s EOS® Digital Rebel XT camera combines outstanding performance and creative control in a small and elegant package for an estimated retail price of under $1,000* complete with zoom lens. This makes the XT an exceptional value in digital single lens reflex cameras. With its DIGIC® II image processor and Canon-designed and manufactured CMOS sensor, the EOS Digital Rebel XT camera has very high 8.
unit sales and revenue figures of both compact cameras and digital SLR cameras combined, according to NPD. In addition, Canon had 62.8 percent of the DSLR market and 18.6 percent of the point-and-shoot market, also both number one according to NPD. Further, according to NPD, Canon had the single best selling digital camera, the PowerShot A75, as well as the best selling digital SLR, the EOS Digital Rebel.
Canon’s patents are a measure of intellectual wealth and corporate ethos. Discoveries in the core technologies are applied to products for industry, healthcare, broadcasting, business and consumers. Because Canon continues to innovate at a furious pace, each new product incorporates significant advances in electronics, mechanics, optics and software. Any new product from Canon, but especially a new digital single lens reflex camera, is the fruit of this intellectual wealth.
the compact, all-in-one 8 megapixel cameras. These tiny pixels necessarily receive less light during exposure. Their meager output signal needs to be amplified heavily in order to get useful information for image processing. That amplification gets applied not just to the image file, but also to any other non-image signal on the sensor, such as heat. The digital noise that results, particularly at high ISO speed settings, is unmistakable. Image sensor size comparison: 8.
II. SUMMARY OF NEW AND IMPROVED FEATURES Design Image Recording • Smallest Canon EOS Digital SLR ever: 25% smaller in total volume and 2.5 ounces lighter than the original EOS Digital Rebel/300D Digital • Among the smallest and lightest cameras in its class • Exterior color choice of black or silver • As with the EOS 20D camera, Canon logo embossed and colored Image • Entirely new 8.
• New white balance correction, same as on EOS 20D, allows fine tuning in Blue-Amber and/or Magenta-Green color ranges, +/- 9 levels • New white balance bracketing in Blue-Amber or Magenta-Green direction, +/- 3 steps • White balance bracketing can be used in combination with white balance correction • Six image processing Parameter Sets provide complete control of sharpness, contrast, saturation, and color tone • New monochrome Parameter Set allows Standard B&W, B&W with filter effects or B&W with toning e
• Built-in flash is 5.
III. FEATURE DISCUSSION New 8 Megapixel Image Sensor The component of the new Canon EOS Digital Rebel XT camera that will receive the most first-look attention is the all-new, Canon-designed and manufactured, 8.0 effective megapixel, single-plate, CMOS sensor. It has a 2:3 aspect ratio (the same as 35mm film), with 2312 x 3472 effective pixels. The imaging surface is 22.2 mm by 14.8 mm, giving a focal length conversion factor of 1.6x. Each pixel is a generous 6.4 µm square.
horizontally. The linear polarized light is converted into circular polarized light by the phase plate. The second crystal plate separates the images vertically, resulting in four duplicate images arranged in a square matrix. The image separation in the horizontal and vertical directions is optimized for the sensor pitch so that false colors and moiré caused by minute horizontal and vertical lines in the subject are reduced while resolution is actually increased.
With the addition of the DIGIC II and some fine-tuning, the AF system of the EOS Digital Rebel camera has been adapted to the Rebel XT camera and is fully compatible with the handling speed of the new camera. The EOS Digital Rebel XT camera uses the same 7-point, TTL-CT-SIR (TTL Cross Type secondary image registration) AF sensor as the EOS Digital Rebel camera, as well as the same 32-bit RISC (reduced instruction set) microcomputer.
The AF point can be selected manually with the cross keys on the back of the camera, or with the electronic dial. The user can avoid pressing the AF point selection button before using the cross keys to select an AF point by activating Custom Function 1-4. The AF point selection operation with the cross keys is similar to the EOS ELAN 7N. With the electronic dial, AF point selection is the same as with the EOS Digital Rebel camera.
the presence and location of a high-reflectance object. The selected pre-flash readings are added and averaged and the output of the main flash is calculated. Even if the subject changes position, reflectance or size, the flash metering remains highly accurate and stable. Some other highly useful changes to the flash system of the EOS Digital Rebel camera have occurred: • User-adjustable flash exposure compensation up to +/- 2 stops in 1/3 or 1/2 stop increments has been added.
For a custom WB setting, first take a picture of a white subject serving as the white balance standard. Then, set the custom WB mode on the onscreen menu and specify that image. In a substantial upgrade from the EOS Digital Rebel camera, the flash color data transmission function from the EOS 20D enables the built-in flash or an accessory Speedlite 580EX to provide flash color information which is used in exposure calculation when the white balance is set to “AWB” or “Flash.
Processing Parameters The Digital Rebel XT camera has the same range of image processing parameters as the EOS 20D: Parameter Set 1 (contrast, sharpness and color saturation set to +1) is optimized for vivid, sharp images upon which no retouching will be performed before direct printing. Parameter Set 2 (contrast, sharpness, color saturation and color tone set to 0, i.e., mid-scale), is optimized for images that will be retouched or adjusted.
C. Fn. 5 controls the AF-assist beam. The three choices are ON, OFF and fire only the external flash. C. Fn. 6 controls whether manually-adjusted exposure level increments are in 1/2 or 1/3 stop units. C. Fn. 7 enables the mirror lockup function. When C. Fn. 7-1 i selected, the mirror locks up when the shutter button is pressed completely. The shot is taken when the shutter button is released and then pressed completely again. The maximum mirror lockup duration is 30 seconds, after which the mirror returns.
Image Display In playback mode, a timely revision of the Jump function enables the user to move quickly to a particular image or group of images, no matter how far one needs to go. Carried forward is the ability to jump 10 frames. New are both the ability to jump 100 frames and the ability to jump to the first image of another day’s shooting. With the jump screen, use the top and bottom cross keys to select the jump method, and then use the left and right keys to jump.
Exposure Controls The EOS Digital Rebel XT camera offers a broad and flexible range of exposure controls. In the Basic Zone modes, evaluative metering, linked to all 7 AF points, is automatically selected. In the Creative Zone modes, partial metering at the center (9% of the viewfinder) and centerweighted average metering are also available. Pressing the left cross key displays the Metering Mode menu.
Power Management The EOS Digital Rebel XT camera is powered by the NB-2LH lithium-ion rechargeable battery pack. This battery is much smaller and lighter than the BP-511 used in the EOS Digital Rebel camera and is a key to the approximately 25% reduction in volume of the new camera relative to its predecessor. The NB-2LH has only 65% of the capacity of a BP-511 (720 mAh vs. 1100 mAh), but the new camera is 35% more energy efficient, primarily because of the DIGIC II image processor.
There are six JPEG quality options, as well as .CR2 RAW only (the new RAW image type featured in Canon digital cameras from the EOS-1D Mark II onward) and a RAW+ JPEG setting in which a RAW file and a Large/Fine JPEG are recorded simultaneously and saved as separate images on the CompactFlash card. The XT is compatible with Type I and Type II CF cards up to 2 GB or larger capacity. Recording complies with Design rule for Camera File System 2.0 (revised to support Adobe RGB) and Exif 2.21.
As with the EOS Digital Rebel model, the EOS Digital Rebel XT camera’s top, front and rear covers are made of special engineering plastic known for light weight, excellent strength and electromagnetic shielding: ABS resin, polycarbonate resin, and polycarbonate mixed with special conductive fibers. The exterior finish is more refined than the EOS Digital Rebel camera’s. The Canon logo is now embossed and colored to give the XT a high-quality appearance.
Interfaces and Compatibility Three interface terminals are provided on the side of the body. The EOS Digital Rebel XT camera has a USB 2.0 Hi-Speed, mini-B connector that transfers data from the camera to a computer approximately ten times faster than the USB 1.1 connector on the EOS Digital Rebel camera. Video output is provided for both NTSC and PAL, and provision is made for the RS-60E3 Remote Switch.
a printer compatible with direct printing, select playback and choose the image to be printed; confirm the print setting and press the Direct Print button while its blue LED is lit. Software The software bundled with EOS Digital cameras in 2004 was composed of products centered on the EOS Viewer Utility. With the EOS Digital Rebel XT camera, the role of EVU will be taken over by a new software configuration centered on the ZoomBrowser EX / ImageBrowser applications supplied with the camera.
EOS Capture v. 1.3 (Windows/Mac) is a remote shooting software application. It allows the camera to be controlled and camera settings to be specified from the computer and saves shot images to the computer. It also allows the user to take shots by pressing the shutter button. It is identical to version 1.2 apart from the addition of the EOS Digital Rebel XT camera to the list of supported cameras. PhotoStitch v. 3.
IV. CONCLUSION When the original EOS Digital Rebel camera was introduced, it was the first interchangeable-lens digital SLR to break the $1,000 price barrier. The approximate retail price was $899* for the body and $999* for the kit with the EF-S 18-55 mm lens. It had 6.3 megapixels, superb, low-noise images, long battery life, and it looked cool. There was nothing even remotely like it. No wonder Canon sold them by the ton and defined the under-$1,000 DSLR category in the process.
