We were very impressed by the SD870 IS's performance in our lab tests. It took the camera 0.9 second to start up and capture its first JPEG. Thereafter, the camera took 1.6 seconds between subsequent JPEGs with the flash turned off, and 2.4 seconds between JPEGs with the flash turned on. Shutter lag measured a stunning 0.4 second in our high-contrast test and 0.7 second in our low-contrast test, which respectively mimic bright and dim shooting conditions. In our continuous shooting test, the SD870 IS captured 1.3 frames per second regardless of image size or compression.
The PowerShot SD870 IS yields very high-quality images with accurate colors and tons of detail, and which are very clean at lower ISOs. The automatic white balance does a very good job of neutralizing colors in different kinds of lighting, but with incandescent lighting, its images have a very slight warm cast. Some people prefer this, since it gives a natural look, as incandescent lighting does give off a warm glow. However, if you prefer a more neutral look in these situations, the tungsten preset does a great job of serving up neutral images.
Canon keeps ISO noise well under control through ISO 200. You probably won't notice much in the way of noise even when viewing ISO 200 images on your monitor, which tends to be more revealing of such noise than prints. At ISO 400, noise becomes readily apparent on monitors, but Canon's noise reduction algorithms manage to smooth it out so it doesn't take on that fine, snowy look that some cameras--including some older Canons--tend toward. Plus, most of this noise should become minimized when making inkjet prints. At ISO 800, noise is much more apparent and should show up in prints, but Canon does a good job of preserving some fine detail, and images show impressive shadow detail for such high sensitivity in a compact camera. Images at ISO 1,600 are very noisy with the SD870 IS, showing large, grainy noise. Most fine detail is lost, giving images a soft look, and a large portion of shadow detail goes by the wayside. Still, given that this camera has a small sensor, the results are somewhat impressive. The images may be usable for small prints, or for use at small sizes on the Web.
Canon's PowerShot SD870 IS is a worthy addition to the company's Digital Elph line. Experienced photographers looking for a pocket camera will lament the fact that the camera doesn't have any manual exposure controls, but if you don't feel the need to tinker with your camera's settings and aren't caught up in the pointless megapixel race, you'll likely be very pleased with this point-and-shoot.