To compare noise levels under real-life conditions we shot the same scene with the Canon A640, Fujifilm F30 and Sony N2 within a few moments of each other using their best quality JPEG modes and each ISO setting. Each camera was set to Auto exposure for this test to also compare how the same scene would be evaluated; this was also necessary in some cases to access the fastest shutter speeds. A neutral density filter was used due to the brightness of the scene and the requirement for high ISOs.

Each lens was adjusted to deliver as close a field of view as possible, although coarse positions on their zooms resulted in variations. The Fujifilm result also shows a larger area due to its lower resolution sensor.

The image above was taken with the Canon PowerShot A640 at 8mm f4, with a sensitivity of 80 ISO; the original JPEG measured 4.62MB. The crops are taken from an area just below and to the left of the centre.

The PowerShot A640 delivers good, clean results up to 200 ISO with noise only becoming visible at 400 ISO and above. At these higher sensitivities though, the A640's noise speckles appear much worse than its rivals, especially compared to the smooth appearance of the Sony N2 crops.

Look a little closer though and it's clear the A640 simply doesn't apply as much noise reduction as many of its rivals. While this means noise speckles are more obvious on the A640's images at high ISOs, there's little of the smearing and subsequent loss of fine detail which plagues so many digital images these days. Just compare the detail in the foliage between the A640 and Sony N2 to see what we mean.

Ultimately which approach is better is entirely personal. Given the choice though we prefer the A640's strategy of retaining detail at the cost of visible noise speckles as it at least gives you the option of applying additional noise reduction after the event using software like Noise Ninja. Sadly on other cameras, that detail could be smeared out by built-in noise reduction and lost forever. To see more examples of the A640 at high ISOs, check our Canon A640 Gallery.

Note: we have compared 100% crops from each camera here measuring 185x136 pixels. Since the Canon A640 and Sony N2 employ higher resolution sensors, these crops represent a smaller area of their total image size than the Fujifilm F30. As such, any artefacts seen on the Canon A640 and Sony N2 crops would appear smaller than those on the F30 crops if the original images were printed exactly the same size.