It becomes clear how much of the Canon EOS 5D's design concept -- and price -- is tied up in its big sensor when you look at the camera's performance, which is generally no better than that of many cameras that cost half or even a third as much. Though not sluggish, this camera is not unusually responsive, nor is it optimised for action shooting.
The Canon EOS 5D starts up relatively quickly, in less than half a second, and there is essentially no shot-to-shot delay. Using a fairly fast-focusing Canon USM lens (the EF 24mm-to-70mm f/2.8L), we measured shutter delay, including autofocus time, at about 0.4 seconds with a bright target and about 0.8 seconds with a dim, low-contrast subject.
The camera will shoot at 3fps in drive mode, a spec matched by several sub-£500 cameras. Its buffer depth, however, is one of the few performance measures where the EOS 5D edges toward its professional EOS 1-series cousins, rather than lower-end models. Using a very fast CompactFlash card, we could capture more than 60 JPEGs or about 20 raw images before the camera paused to clear space in the buffer.
For shots where you must avoid even the slightest vibration, there is a well-conceived mirror-up mode, which you operate by pressing the shutter once to swing the mirror up and a second time to trip the shutter. It can be combined with the self-timer to fire a few seconds after the mirror swings up without the photographer touching the camera.
A new autofocus system, with nine visible focus zones and six invisible 'assist' zones, graces the EOS 5D. You can designate any one of the nine sensors to be the only active one, or you can use all nine at once, which can be handy for sports action. Overall, we found the EOS 5D's AF performance to be midlevel: generally quick and quite capable for the vast majority of tasks but still no match for the top-line pro photojournalism cameras when shooting fast action.
The camera's viewfinder covers approximately 96 per cent of the actual image area. It certainly provides a bigger image than the viewfinders on cameras with smaller APS-C sensors, and it's fairly bright and sharp, though again not quite up to the standard of a high-end pro 35mm-format body. The focusing screen is interchangeable -- a grid screen (Ee-D) and a screen optimised for manual focusing (Ee-S) are available.
The 64mm (2.5-inch) LCD is big, sharp and easy to view from just about any angle. It's as good as any we've seen. Canon does not provide a protective plastic cover for it, nor could we see any way to mount one, and we'd be somewhat concerned about scratching it if we owned one.
The Canon EOS 5D's synchronisation speed with shoe-mount flashes is 1/200 second, although the FP-sync mode allows certain Canon flashes to sync up to 1/8,000 second with some significant limitations. For studio flash units, Canon specifies a sync speed of 1/125 second. The camera incorporates Canon's E-TTL II flash exposure control system, which works with any EX-series Canon Speedlite.