This first shot was taken with the IXUS 100 IS / SD780 IS zoomed-out and set to its lowest 80 ISO sensitivity. Under these bright conditions it represents a best-case scenario, and the crops from well-corrected areas are certainly sharp and detailed, with only the faintest smattering of noise textures in shadow areas. Our main results pages revealed softness in the corners of images at wider focal lengths and there’s also evidence of that here.

Landscape: 3.55MB, Program, 1/200, f9, ISO 100, 5.9-17.9mm at 5.9mm (33mm equivalent)

						Another shot taken under bright light with the lens zoomed-out and the sensitivity nudged up to 100 ISO. The areas cropped here are sharp and detailed, although the flat areas of blue sky reveal a slight increase in visible noise textures to the pixel peepers out there – as also seen in our High ISO Noise results page. There’s also some softening again in the extreme corners, although the subject matter here is relatively forgiving.

Landscape: 3.65MB, Program, 1/800, f5.8, ISO 200, 5.9-17.9mm at 17.9mm (100mm equivalent)

Optically we’ve few complaints here, but the increase to 200 ISO has resulted in greater noise levels and a softening of ultimate detail.

The crops of the subject are sharp, although like the sample above, there’s visible noise appearing in flat colour or shadow areas and a lack of crispness to edges.

Viewed at 100%, the background is a little blurred, but like other compacts you won’t get the really small depth-of-field effects on a DSLR.

The depth-of-field here is fairly small, with a tightly defined strip of sharpness across the middle of the shot where we’ve taken the crops from.

In this area, the crops are sharp and detailed, and unlike many compacts, there’s no coloured fringing to complain about in the corners.

The boost to 400 ISO has further softened edges though.

As seen above though, the increase to 400 ISO has resulted in greater visible noise in shadow areas or those of flat colour, along with a softening of edges.

It’s still ok for smaller prints, but pixel-peepers or those wanting laregr prints will want to stick to lower sensitivities.

As you’d expect, there’s another increase in noise artefacts and some smearing due to noise reduction. But the crops do still contain a reasonable amount of detail and it’s certainly not a dramatic drop beyond 400 ISO. Still best-reserved for smaller prints though.

Like most compacts, 1600 ISO is a step too far and should only be used for emergencies, or very small reproductions.

The Canon then goes onto offer a 3200 ISO option as a Scene Preset, albeit at a greatly reduced resolution of 2 Megapixels. You can see a sample of it and other sensitivities in our High ISO Noise results page.