As for performance, the 40D is reasonably speedy for its class, and roughly 20 per cent faster overall than the 30D. But it still can't keep up with the faster, albeit lower-resolution, D80. From a cold start to first shot takes only 0.3 seconds and under optimal conditions it can focus and shoot in only 0.4 seconds. A healthy buffer and fast card writes allows the 40D to maintain that pace from shot to shot for both JPEG and raw. Flash recycle time adds slightly less than 0.2 seconds to that.
The 40D has slow- and high-speed burst modes which test out at 3.1 frames per second (fps) and 6.3fps, respectively; the slower mode is for preventing buffer lockups when using a slow CF card. We also found the slower mode a useful speed option when shooting with the Speedlite 580EX flash with sluggishly recycling alkaline batteries. Note that in the case of the 40D a 'slow' CF card does not mean 'anything slower than UDMA'. It doesn't support UDMA, and seems to have sufficient buffer to maintain maximum throughput even with a last-generation SanDisk Extreme III (133x) card.
However, the camera does hit one sour performance note: leisurely low-contrast focusing, which ratchets up low-light lag to 1.2 seconds. This is despite Canon's claim of a 30 per cent increase in AF calculation speed. Though not uncommon for a dSLR, we really expect better, especially for this price class. Canon rates the battery, the same 1,390mAH BP-511A used by the 30D, at 1,100 shots (sans flash). Though this is reasonably long, Canon lags behind many of the other manufacturers for providing intelligent power display and estimates of power remaining. The large, bright LCD is easy to view, but like even the best camera LCDs, it renders relatively poor representations of colour and exposure.
(Shorter bars indicate better performance)
|Time to first shot||
||Raw shot-to-shot time||
||Shutter lag (dim light)||
||Shutter lag (typical)||
(Longer bars indicate better performance)