To compare noise levels under real-life conditions we shot this scene with the Canon IXUS 200 IS / PowerShot SD980 IS, the IXUS 120 IS / SD940 IS and the Nikon COOLPIX S570 at each of their ISO sensitivities.

The lenses were set to approximate the same field of view.

The above shot was taken with the the Canon Digital IXUS 200 IS / PowerShot SD980 IS Digital ELPH in Program mode with the lens at a wide angle setting of 5.3mm (30mm). The exposure was 0.8 seconds at f3.2. The crops are taken from the area marked with the red square and presented below at 100%.

At the lower ISO settings the IXUS 200 IS / SD980 IS turns in an excellent performance. Even at the lowest ISO settings long exposure time can produce noise, but there's no evidence of it here. These shots are also well exposed with good detail in the shadows, it's not unusual for compact cameras to underexpose in these sutuations, but the IXUS 200 IS / SD980 IS hasn't succumbed to that problem.

A casual observer probably wouldn't notice much evidence of noise up to 200 ISO, and if you were looking at these shots at reduced magnification on a screen you be very hard pressed to spot the difference between the 200 ISO shot and the 80 ISO one. But careful examination of the 100 percent crops reveals noise is starting to make an impact (albeit negligible) at 200 ISO.

At 400 ISO there's a further slight drop in image quality. The noise is gaining ground and the processing required to keep it in check is causing a degree of softening, but all the same, the image quality is fairly acceptable. Beyond that, at 800 and 1600 ISO it's the usual story of progressively worsening noise, but from 400 ISO onwards the deterioation is gradual and proportionate, and at each stage Canon's noise reduction algorithms manage to strike a good balance between keeping the noise within accepatable limits and producing artefacts.

The IXUS 200 IS / SD980 IS has a 3200 ISO scene mode which produces 1600x1200 pixel sized images. The resolution is lower and the image quality is not great, but for shots that really matter where you can't use a flash indoors, this is certainly a worthwhile feature to be able to fall back on.

Overall, the results for the IXUS 120 IS / SD940 IS compare very favourably, perhaps unsurprisingly, there's not a lot in it. There is one interesting thing worth noting though. At every ISO sensitivity up to 400 ISO the IXUS 200 IS / SD980 IS appears to have the edge - literally - the crops are sharper and show more detail and less noise. At the higher ISO settings of 800 ISO and beyond the situation is reversed with the IXUS 120 IS / SD940 IS gaining the upper hand.

The Nikon COOLPIX S570 provides stiff competition for both Canon compacts when it comes to high ISO noise performance. It's almost too close to call, but we'd say it has the edge over both the IXUS 200 IS / SD980 IS and the IXUS 120 IS/ SD 940 IS in the lower sensitivity range. From 200 ISO upwards, however, there's more noise and less detail in the crops from the COOLPIX S570. It also has difficulty maintaining accurate white balance and good colour saturation as the ISO sensitivity increases, a problem neither of the Canon compacts suffered from.

Now head over to our Canon IXUS 200 IS / SD980 IS gallery to see some more real-life shots in a variety of conditions.

Canon IXUS 120 IS / SD940 IS		Canon IXUS 200 IS / SD980 IS		Nikon COOLPIX S570
80 ISO		80 ISO		80 ISO
100 ISO		100 ISO		100 ISO
200 ISO		200 ISO		200 ISO
400 ISO		400 ISO		400 ISO
800 ISO		800 ISO		800 ISO
1600 ISO		1600 ISO		1600 ISO
3200 ISO (1600x1200)		3200 ISO (1600x1200)		3200 ISO