The SD4000 IS produced some of the best photos we've seen from a camera using a backside-illuminated CMOS sensor. Sensitivities for these cameras generally start at ISO 125, so even if you're shooting with plenty of light, you'll still end up with softer fine details. However, Canon does an excellent job at balancing noise and noise reduction, leaving enough detail intact that photos are usable up to ISO 1,600. At ISO 3,200, though, subjects get overly smeary and painterly. They might be good enough for Web use without any cropping or enlarging, but the noise causes noticeable yellow blotches. While the results overall aren't earth-shattering, they are excellent for an ultracompact camera.
The Sony Cyber-shot DSC-TX7 uses a similar BSI CMOS sensor to the Canon's and is likewise capable of very good low-light photos. The SD4000 IS got a slightly higher photo quality rating because its images were better across the entire ISO sensitivity range. On a side note, despite appearances, the Sony's white balance is more accurate.
The SD4000 IS is excellent in Macro mode, producing sharp photos with lots of fine detail. The camera can focus on subjects as close as 1.2 inches from the lens. The camera will automatically switch to Macro in Auto when appropriate or you can select it in Program and Aperture- and Shutter-speed-priority modes.
Canon's Digital Elphs are usually designed for snapshot photographers who don't want to fuss with settings. The SD4000 IS breaks that tradition by offering Shutter-speed- and Aperture-priority modes. Shutter speeds can be set from 15 seconds to 1/2,000 second. Apertures include f2.0, f2.2, f2.5, f2.8, f3.2, f3.5, f4, f4.5, f5, f5.6, f5.9, f6.3, f7.1, and f8. With the lens fully extended, you just get five, though: f5.3, f5.6, f6.3, f7.1, and f8.0. Being able to control shutter speed is great for freezing or blurring motion, while the aperture control gives you the ability to select how much of a scene you want in focus.
There is minor barrel distortion at the camera lens' wide angle. There a appears to still be some when the lens is fully extended, too, but not enough to be concerned about. Sharpness is very good edge to edge.
The amount of fringing on high-contrast subjects is above average. It's certainly not uncommon to see, but for a top-of-the-line camera, I expect less. Still, it was rare that it was at levels like this man's shoulders where it would need a lot of photo editing to resolve. Also common are clipped highlights, but I've noticed that BSI CMOS sensors seem worse than CCD sensors found in most compact cameras. Manufacturers such as Sony have been solving this to some degree with high-dynamic range modes, but Canon doesn't offer one on this model.
Color accuracy is excellent, producing bright and vivid results. If you like to experiment there are options for setting color saturation, sharpness, and contrast. Exposure is generally very good, though, highlights tend to blow out. Lastly, auto white balance is generally very good, though it is slightly warm indoors, while the custom setting used in our lab tests was cool.
Canon introduced a few new creative shooting modes in 2010. This is Miniature Effect, which blurs the top and bottom of the frame and boosts contrast and color saturation to make subjects look like painted miniature models. It works to some degree, but is not as convincing as true tilt-shift photography, which is what the effect is based on.