Canon's SD series, also known as the Digital Elph line, is an exercise in slow evolution. Since the company has hit on a very successful design, these compact point-and-shoots typically see only minor tweaks from year to year. This year's follow-up to the popular SD700 IS is the new PowerShot SD850 IS. The main differences between the two include a jump up to 8.3 megapixels (from 6.2 megapixels) and the new Digic III image processor, which brings with it face detection and a higher top sensitivity of ISO 1,600 (up from ISO 800). The SD850 sports nearly everything you'd want in a point-and-shoot.
The only thing you might want to change would be the 4x optical zoom lens. The SD850 IS's lens starts at an equivalent of 35mm and ends at 140mm. For a compact camera such as this, I prefer a lens that starts wider, such as the 28mm-to-105mm lens found on the PowerShot SD800 IS. The wider lens lets you fit more people into those group photos, or get closer to your subject, such as in a nightclub. Of course, we can't really hold this against Canon in this case, since the SD800 IS basically offers everything the SD850 IS does, but with a different lens. So if you side with me in the lens debate, check out the SD800 IS. Both cameras include Canon's very effective optical image stabilization to help keep your images sharp even if your hands aren't very steady.
Designwise, the SD850 IS is almost identical to the SD700 IS. The only real difference is the colors that adorn its body. That means that Canon hasn't fixed the wacky on/off button that irked us on last year's model. It sits to the right of the tiny viewfinder above the 2.5-inch LCD screen on the camera back. The button is in an awkward place and is also rather small and completely flush with the camera back. We've never had much of a problem with positioning the power button atop the camera and aren't sure why Canon decided to put it here in the first place. Maybe they'll move it next year. We also found that the mode dial, embedded into the right side, felt a bit flimsy and occasionally skipped a couple of notches when we were trying to move only one. Once we got used to it, though, it wasn't much of a problem.
Compared to last year's multicontroller pad, which was perfectly fine, the SD850 IS's pad is an improvement. A raised ring around the pad gives it better tactile response. Plus, when you rest your thumb in any particular direction, a graphic appears on the LCD to show you what you'd do if you press fully. This came in handy, since you don't have to move your eyes away from the screen when changing settings. Plus, it makes it easier to discern the controller's multiple functions, since the onscreen graphic only shows the function that is active in the mode you're currently using.
For the most part, the PowerShot SD850 IS turned in a performance that is equal to, or faster than, that of the SD700 IS, despite the increase in megapixels. The SD850 IS took 1.2 seconds to start up and capture its first JPEG. Subsequent JPEGs took 1.7 seconds between shots without flash but slowed significantly to 3 seconds between shots with the flash turned on. This is one area where the SD700 IS outperformed; it took 1.9 seconds between shots with its flash enabled. The SD850 IS's shutter lag measured 0.5 second in our high-contrast test and 0.7 second in our low-contrast test, which mimic bright and dim shooting conditions, respectively. The other area where the SD850 IS lags behind its predecessor is continuous shooting. The SD850 IS yielded about 1.4 frames per second (fps) regardless of image size, while the SD750 IS was able to churn out a more impressive 2.1fps.