Other interesting features include Focus Check, which brings up a magnified thumbnail, indicating your focus point and the surrounding area, that you can quickly zoom in on. It operates either as one of your Review options after every shot or as a Display option during playback; the former is annoying, the latter, quite nice. The optical image stabilizer provides a Panning mode option, for combating vertical shake but not horizontal motion, rare but not unique in its market, which is useful if you like to shoot sports like cycling, track, or car racing.
As with most point-and-shoot cameras, I find the face-detection marginally useful at best, despite Canon's claimed improvements; it's simply too inconsistent and you end up wasting time forcing it to detect the right face (or any face at all). In fact, I'm coming to think it's designed to make up for deficiencies in most of these cameras' AF auto-selection point technologies, like Canon's AiAF. As with most of the systems, AiAF routinely chooses odd subjects to lock on. Face detection forces the AF system to concentrate on more obvious choices, like people. So even if the camera doesn't actually detect a face, it usually ends up focusing on one without realizing it. You just lose some of the ancillary benefits the camera's programmed to provide, like optimizing exposure and white balance for skin tones. But at the moment both remain poor substitutes for using centerpoint focus and recomposing. Canon also makes a big deal about its Motion Detection, which supposedly works with Auto ISO to kick up the shutter speed when the subject matter warrants it. But I couldn't force it to engage.
Some aspects of the SD790 IS' performance are excellent, while others are below par. It wakes up and shoots in a fairly average 1.2 seconds, and delivers great focus-and-shoot times of 0.4 second and 0.5 second, in optimal and suboptimal lighting, respectively. But two consecutive shots take about 2 seconds and adding flash bumps that up to 3.5 seconds, both of which fall behind much of the competition, as well as its predecessor the SD750. The same goes for its modest 1.3 frames per second typical burst-shooting rate. Canon rates the battery at 330 shots (using CIPA-standard methodology), which is relatively good for a point-and-shoot. And the 3-inch LCD remains usable in bright sunlight, though you'll have to pump the brightness up, which may cut into that battery life. It has a nice wide viewing angle for impromptu slide shows, but looks fairly coarse, like many of its 230,000-pixel competitors.
One aspect Canon hasn't messed with is photo quality: the SD790 IS' is probably the best I've seen from a snapshot camera to date. By most measures--color, exposure, sharpness, and noise--the SD790 leads or is one of the leaders of the pack, both by the CNET Labs' numerical test results and by visual inspection of test photos. (Click through the slide show for more on photo quality.)
The Canon PowerShot SD790 IS' great photos more than make up for its mixed performance. If you don't need a tinier profile, zoom during movie capture, an optical viewfinder, or semimanual exposure controls, and the odd design doesn't put you off, you should definitely check it out.
(Shorter bars indicate better performance)
|Time to first shot||Flash shot-to-shot time||Typical shot-to-shot time||Shutter lag (dim light)||Shutter lag (typical)|
(Longer bars indicate better performance)