Representing a more significant leap over the EOS 30D than the 30D was beyond the 20D, the Canon EOS 40D features a redesigned body and menu system, introduces some long-requested features, integrates some of the new technology from the EOS 1D Mark III and delivers a considerable bump in resolution and performance.
All of that, plus a solid overall increase in speed over its predecessor, make it a no-brainer upgrade from previous models, a substantially better option than its down-the-line sibling, the EOS 400D and a good complement to the EOS-1D Mark III. You can buy the 40D as the body only for around £780, or for more in a kit with a lens included. We've seen the 40D with an 17-85mm, f4-5.6 IS USM lens for around £1,000, but other offers may become available.
Despite the growth of the LCD from 64 to 76mm (2.5 to 3 inches), the body size and weight of the 40D is the same as that of the 30D: 145 by 109 by 74mm and roughly 820g. As with its predecessor, the body feels very solid and well made, one of the important advantages it has over the flimsier-feeling 400D.
Canon has added dust- and weatherproofing on the CF slot, the buttons and all connection points, and has implemented the same integrated sensor-cleaning system that's in the Mark III series. The latter vibrates the sensor to dislodge dust during start-up and shut-down (pressing the shutter cancels cleaning during start-up), and if that doesn't work, a Dust Delete Data option enables the camera to analyse and remember where it senses dust and algorithmically remove it from photos.
The larger LCD did make it necessary to rejigger some of the controls. The Review, Delete, Jump, Info and new Picture Styles buttons now sit below the LCD rather than to the side, and the buttons are substantially smaller than before. They also sit flatter and more flush with the body, making them harder to feel and press. Along the same lines, the Metering/WB, AF/Drive, ISO/Flash compensation and LCD backlight buttons, which seem to rise slightly higher than previously, feel identical and impossible to differentiate from one another.
On the upside, the 40D has a bigger, more tactile mode dial, with three slots for User settings (the 30D had none). Although we find these invaluable, there's one behaviour that really annoys us: if the camera goes to sleep, it resets any setting overrides you've made while in one of the user modes.
Canon has also redesigned the grip, adding a curved indentation just below the ledge with the shutter button, where your middle finger falls. It's a subtle but helpful ergonomic enhancement that makes the grip feel a little more solid. Canon has also redesigned the menu system, which is now far easier to read and navigate.