The EOS 450D is more than merely an upgrade of the 400D. While it does share a number of components and features, such as the exposure meter and shutter mechanism, it has a new DIGIC III processor, a new nine-point wide area AF system with a cross-type centre sensor, and more importantly a newly-designed sensor.
The first thing that strikes you about the 450D is how small and light it is. It measures 128.8 x 97.5 x 61.9 mm and weighs approximately 475g body-only, slightly larger but 35g lighter than the EOS 400D. It is also 20g lighter than the Nikon D60 and over 50g lighter than Sony's A200. The camera body is plastic, and unfortunately the low weight does lend it an air of flimsiness which is largely unwarranted by the actual build quality. The plastic is a little thin in places, but overall the camera is quite sturdy.
The small body can be a bit of a problem for anyone with large hands, because the handgrip is also very small, with quite a narrow gap between it and the side of the lens mount. However the grip is covered in textured rubber and feels very secure and balanced, and the positioning of the controls is very intuitive especially for anyone who has owned a previous Canon DSLR. On the top and back of the camera the layout of the buttons is very similar to the 400D, although the larger screen has meant that some have been relocated, including making room on the down-arrow of the D-pad for the Picture Style button.
Picture Style is a new feature for the 450D, providing a quick and easy menu for customising the image processing, with seven pre-set and two user-defined settings for contrast, saturation, sharpness and colour tone, with a wide degree of control for each parameter. Most DSLRs have an image control feature of this type, but Canon's is particularly well designed and very easy to use.
Main shooting mode selection is via a large dial on the top plate, with the usual choices of program, aperture and shutter priority and manual exposure, as well as the A-Dep mode which automatically maximises depth of field, and a small selection of point-and-shoot scene modes that will be familiar to compact camera users. Shutter speed and aperture setting are adjusted via a single data entry wheel located just above the shutter button.