The faster DIGIC III image processor gives the 40D significantly faster performance than its predecessor, with a maximum shooting speed in continuous mode of 6.5 frames per second. It is worth noting however that it only produces this speed in JPEG mode. When shooting in 14-bit RAW mode the continuous shooting speed is closer to 2.5 frames per second, which is nonetheless still pretty quick by any standard. The buffer can hold 75 JPEG images or 14 RAW.
The main new features of the EOS 40D's specification are all aimed at improving picture quality, and I am happy to report that they have been a resounding success. Quite simply, the 40D has the best final image quality of any comparable mid-range camera that I've tested so far. The depth and richness of colour, the exceptionally wide dynamic range and the massively impressive high-ISO noise control justify Canon's decision to stick with the 10MP sensor. While the level of absolute detail may not be as high as its 12MP and 14MP rivals, the sharpness and clarity of the pictures are breathtaking. The 14-bit RAW files contain more luminance and colour information than is normally visible in 8-bit JPEG images, and as a result it is possible to make quite significant adjustments to exposure in RAW post-processing without impacting image quality, allowing details to be pulled out of shadows and highlights that 12-bit cameras would miss. Images shot at the minimum 100 ISO setting are flawlessly smooth, and even at the normal maximum of 1600 ISO the level of noise is amazingly low, and has virtually no impact on colour reproduction. The EOS 30D set a very high standard for image noise performance, but the 40D exceeds even that.
The Canon EOS 40D is facing a lot more competition than any of its predecessors, but still manages to set the benchmark for mid-range semi-professional DSLR cameras. Improvements to build quality, performance and image quality are a significant step up from the EOS 30D, and compare well with anything else on the market. However the live-view feature and the environmental sealing aren't good as some of its competitors, and the control interface can be a bit fiddly too. Nonetheless, the 40D is genuinely pleasant camera to use, and the fantastic image quality more than makes up for any slight shortcomings and makes it worth the slightly steep asking price.