Canon 40D Performance

Above average speed for a semi-pro DSLR.

Startup and shut-down times are quite fast: Not quite as fast as some, but the difference will really be academic. (The difference between 0.3 and 0.4 second really isn't likely to make the difference between a winning image and a lost shot.) Buffer clearing time depends on the image size and quality, burst length and how fast the card can be written to, to the flush the buffer. Live View mode increases RAW buffer clearing time significantly, but has very little impact on cycle times (see below).

Mode switching is very fast. Almost imperceptible.

The Canon 40D's AF performance is quite fast, a significant improvement over the 30D in most respects. Full autofocus lag is almost twice as fast at 0.128s vs the 30D's 0.245s, though prefocused, lag is just slightly faster (0.061s vs 0.068s). Continuous AF mode shutter lag is a bit longer though, at 0.153s vs the 30D's 0.105s, but shutter lag when manually focusing has been cut in half at 0.078s vs 0.154s. We were pleasantly surprised that the Live View modes add minimal shutter delay; not nearly as much as we're accustomed to seeing.

Cycle times for large/fine JPEGs are similar to the 30D, but have improved when shooting RAW, to 0.23s for 14 frames vs 0.27s for 11 frames for the 30D's smaller RAW files. Continuous mode has improved from 5 fps to over 6 fps with similar buffer depths. As with shutter lag, Live View mode has little impact on cycle times, though it does affect buffer clearing times. Flash recycling after a full power shot is quite fast at 2.9 seconds, slightly faster than the 30D's 3.0 seconds

Download speeds are also very fast, so you won't feel the need for a separate card reader.

Battery

Excellent battery life for a lithium-ion design, as long as Live View is used sparingly.

The Canon EOS 40D uses a custom rechargeable lithium-ion battery pack for power, and comes with both a single battery and charger. Though runtime is excellent, we do recommend picking up a spare battery and keeping it freshly charged and on-hand, especially if using Live View mode.

The table above shows the number of shots the camera is capable of (on either a fresh set of disposable batteries or a fully-charged rechargeable battery as appropriate), based on CIPA battery-life and/or manufacturer standard test conditions.

(Interested readers can find an English translation of the CIPA DC-002 standards document here. (180K PDF document))

Storage

The Canon EOS 40D stores its photos on CompactFlash memory cards, and no card is included with the camera. The chart below shows how many images can be stored on a 512MB card at each size/quality setting.

We strongly recommend buying a large capacity CompactFlash memory card. At least a 2GB card, preferably a 4GB one, to give yourself extra space for extended outings. (Check the shopping link above, cards are really cheap these days, so no reason to skimp.)