The 12.1MP rear-illuminated CMOS sensor used in the Canon IXUS 230 HS does a superb job of retaining detail levels and low noise at high sensitivities.
Pictures taken between ISO 100 and ISO 400 are incredibly difficult to distinguish from each other, and the slight softening that occurs at ISO 800 is only noticeable on very close inspection.
Images taken at both ISO 1600 and ISO 3200 show signs of noise on close inspection and a slight drop in colour saturation, but the noise is fine grained with no obvious colour speckling and should still be suitable for prints up to 10x8 inches.
This is superb performance for a compact camera at this price point.
In its default settings the Canon IXUS 230 HS produces vibrant, but natural looking colours. Reds and warm tones tend to come across a little stronger than cooler tones, which isn't necessarily a bad thing. If colours need a boost, then the Super-Vivid picture style bumps the colour saturation up to unnatural levels, and other effects such as the Toy Camera mode can result in a more subdued palette.
Evaluative metering strikes a good balance between retaining detail in highlights and shadows and is incredibly hard to fool, providing adequate exposures in very challenging conditions. The balance struck between flash and ambient exposures in low light conditions is also very good, resulting in natural looking images.
Whether Face Detection or normal focusing is enabled, autofocus is blisteringly fast, even in low-light conditions, which enables quick snapshots to be taken confidently. The built-in image stabilisation system also helps to tame camera shake at the telephoto end of the zoom, and in low light conditions.