The EOS 40D replaces the 30D, which itself replaced Canon's mid-range 20D model. These were all pitched above the basic entry-level 300D/350D/400D series, with metal build, faster continuous shooting and more advanced controls.
But something odd happened with the 30D. It was a semi-pro camera with an 8MP sensor when the cheaper model in the range - the 400D - had 10 million pixels. Canon's put that right with the EOS 40D, but the improvements in this camera go far beyond a simple sensor upgrade.
First, there's the obvious. The 40D has a huge 3in LCD that makes examining saved pictures and showing them to others much easier. It also has a Live View mode, where you can compose the shot on the LCD rather than the viewfinder.
Inside, Canon's latest DIGIC 3 processor offers 14bit data for improved tonal rendition, better power consumption (Canon quotes a battery life of 800 shots) and a 0.15 second start-up time.
The continuous shooting speed goes up, too. It was impressive enough in the old model, but the 40D can now shoot at 6.5fps. This is twice the speed that other cameras in this price bracket can manage and the Canon can keep it up for 75 JPEGs or 17 RAW files.
The 40D has the same 'integrated cleaning system' now appearing on all EOS SLRs and a Highlight Tone Priority mode, which attempts to tackle that bugbear of digital sensors - blown-out highlights.
Apart from the shooting speed, the 40D doesn't necessarily appear to do much more than other 10-megapixel SLRs costing a lot less money. Much of its appeal, though, is in its construction, design and build quality - the magnesium alloy chassis is a step up from the plastic construction of cheaper cameras.
It's a little bigger than the current crop of entry-level SLRs, too and this makes it easier to hold. In addition, it shares the control layout of higher-end EOS cameras, which is based around a trio of dual-function buttons on the top plate and two control wheels - one at the front at the top of the grip and a large, spinning dial on the rear of the camera.
On the top of the camera is a mono status LCD - cheaper cameras usually display this information on the main LCD, which some users may find annoying. However, when compared with the 400D, the 40D isn't necessarily better.
The 400D's information display is superb, while the 40D's is harder to see if you choose to display it on the main LCD instead. In some ways, the great design of the low-cost 400D has rather shown up some shortcomings in the more expensive model's layout.
And the rear control dial does take up the space normally reserved for a four-way controller. These four-way functions (mostly for menu navigation) are taken care of by a small thumbstick and while this does feel more positive than most, it's still not as good as a decent navipad.
A few negative remarks, then, but this is only in comparison to the little 400D, which has such an excellent control layout and user interface - the longer you use it, the more you appreciate it. Generally, the 40D's controls are very good, including their 'feel', their layout and their accessibility. For keen photographers who've advanced beyond the basics, it'll prove a significant step forward over an 'amateur' camera.
Don't expect a big leap forward in image quality. In side-by-side tests against the 400D, the 40D's images looked virtually identical. In general testing, its pictures did look a little more vivid, so maybe the new processing does make a difference - though the differences aren't obvious and, without shooting the same shots on both cameras at the same time, it's impossible to be sure.
One respect in which they're very similar, though, is the 'glassy' look to JPEG images when viewed at 100% magnification on-screen. Coarse detail looks fine, but fine textural detail can look quite soft.
This seems to be a characteristic not just of this camera but other EOS SLRs - we noted it with the 350D and the 30D too.
It seems to be a deliberate in-camera processing decision (it certainly produces low noise levels), but if you want your images to have real 'bite' in textural areas (stone walls, distant vegetation) you're much better off shooting RAW files and processing them later with the Digital Photo Pro software supplied with the camera.
This can also simulate the camera's different Picture Styles if you don't want to choose them at the time of shooting. The Landscape style produces terrific blue skies, incidentally, but the Neutral and Faithful styles seem similar and produce flat results with little obvious appeal.
This camera comes with software for your own Picture Styles - in other words, you can customise how the camera processes the images. It's more likely, though, that serious users will prefer the extra flexibility and quality of RAW files.
The Highlight Tone Priority mode is a nice idea, but its results are subtle. The manual seems to suggest that it compresses tones higher than 18% grey to produce better gradation in the highlights, but its effects will only be apparent with certain types of image. It's nowhere near as effective as the highlight recovery in many third-party RAW converters. Lightroom 1.2 supports the 40D's RAW files, for example, and can extract far more highlight detail than this.
In terms of tone and colour, the 40D's images are excellent, but its JPEGs aren't as good as its RAW files for definition. Luckily, the DIGIC III processor makes light work of saving RAW files and these days high-capacity memory cards are cheap.
This is the point: don't buy an EOS 40D expecting a big jump in image quality, because you won't get it. The pictures from the 400D will be just as good, as will those from a host of other 10-megapixel models, especially if you habitually shoot JPEGs.
But the 40D is better made, more durable, with more features, much faster continuous shooting and a more 'professional' control layout. What you're getting here is not necessarily better photos, but a better camera.