Very good to average speed for a consumer camera, depending on the operation.

The Canon PowerShot SX100 IS's performance ranges from very good to about average, depending on what you're trying to do. It starts up fairly quickly considering its large 10x optical zoom lens, which extends forward on power-up, though mode switching is a little pokey. Shutter response is very good at both wide angle and telephoto, at 0.53s and 0.48s respectively, and "prefocusing" the camera by half-pressing and holding down the shutter button before the final exposure results in a good lag time of 0.088 second. Shot-to-shot cycle times are on the slow side of average for a long zoom, at about 1.98 seconds for large/superfine JPEGs, and the camera appears to capture shots continuously in single-shot mode without having to stop and clear the buffer. Continuous mode is a little sluggish, at 1.08 frames-per-second for large/superfine images, though the camera captured over 20 shots at this rate without having to clear the buffer. The flash takes 12 seconds to recharge after a full-power shot, which is quite slow. Connected to a computer or printer with USB 2.0, however, download speeds are zippy enough. Bottom line, the Canon SX100 IS is responsive enough to handle most family photo opportunities, though not quite fast enough to match high-paced action, and the flash charge time may hold you back in some instances.

Battery
Good battery life with NiMH rechargeables, though limited performance with alkaline cells.

The Canon PowerShot SX100 IS uses two AA-type batteries for power, and ships with a set of ordinary alkaline cells. As always, we strongly recommend you pick up a couple of sets of good-quality NiMH rechargeable batteries and a good-quality charger, as they'll save you many times their cost over the life of the camera.

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 PowerShot SX100 IS accepts SD/MMC memory cards, and comes with a 16MB starter card.

We strongly recommend buying a large capacity SDHC or SD memory card at least a 1GB card, preferably a 4GB one, to give yourself extra space for extended outings and video. (Check the shopping link above, cards are really cheap these days, so no reason to skimp.)