The original Canon EOS Digital Rebel was the first digital SLR (DSLR) to break the US$1,000 price barrier. Since then, Canon has released other Rebel models with smaller bodies and larger feature lists, with the latest being the EOS Rebel XSi.
It's easy to look at the Canon DSLR product line and slot the cameras into "beginner," "intermediate," and "advanced" categories, but to call the XSi a beginner or starter DSLR is a misnomer. The XSi is an incredibly capable camera that just happens to be small, and it yields great images.
I've never been a fan of the smaller Rebel bodies because they've always felt cramped in my hand. With the XSi, Canon made a number of tweaks to the camera's body and handgrip, making it more comfortable to hold and use than previous Rebels. If you're looking for a lightweight, comfortable camera, the XSi is hard to beat.
The XSi also sports some important interface changes. The ISO control is now a single button located behind the shutter release. With the control in this new position, you can very easily access ISO with your shutter finger, without ever taking your eye from the viewfinder. Because the in-viewfinder display now shows ISO, you can easily make ISO tweaks while looking through the camera. The XSi also has a larger LCD than previous Rebels, which means some buttons have had to be moved. But all essential controls (Program Shift, Exposure Compensation, and ISO) are easily accessible while shooting.
The camera still lacks a dedicated status screen. Instead, the LCD is used for regular camera status. Fortunately, a proximity detector automatically disables the screen when you look through the viewfinder. Personally, I prefer a dedicated top-mounted display, as it's easier to see, less intrusive in low light, and less of a battery drain.
The XSi has a 12-megapixel sensor and a Digic III image processor; the previous Rebel model, the EOS Rebel XTi, had a 10-megapixel sensor and a Digic II processor. The new hardware produces image quality that is top notch, and the camera performs great in low light, even at ISO 1600.
Live View allows you to use the LCD as a viewfinder. As with the EOS 40D, focusing in Live View is a bit cumbersome. The XSi provides two focusing modes when in Live View, and both are fairly slow. But if you're shooting over-the-head or tripod-mounted shots, or are in any other situation where getting your eye up to the viewfinder is a problem, Live View is a welcome addition.
You can buy the XSi body only ($700), or purchase a kit ($800) that includes a new 18-55mm lens. Small and lightweight, this lens is far superior to Canon's previous 18-55mm lens. It offers very good sharpness but is not plagued by the chromatic aberration (color fringing) troubles of its predecessor. Most importantly, the lens now includes Canon's excellent Image Stabilization technology. With stabilization, you'll be able to shoot handheld in more situations, without worrying about camera shake softening your images.
How it compares
The XSi delivers image quality that's identical to Canon's EOS 40D, but for almost $350 less. What are you giving up if you go for the XSi? The 40D has a faster burst rate (five frames per second versus the XSi's three), more customization, the ability to change ISO in fractional stops, and one or two other high-end options. Most importantly, its control layout features more dedicated buttons, which can make reconfiguring the camera much easier; it also sports a top-mounted status display in addition to the rear LCD.
The XSi, though, scores for its size. If you're looking for a small, light camera that's easy to pack, and that you're more likely to carry, then the XSi is a better option than the EOS 40D, provided you can live without the features found in the latter.
Macworld's buying advice
The EOS Rebel XSi is a great DSLR, no matter how you look at it. If you're shopping for a DSLR that costs less than a grand, this camera must go on your short list.