White Balance

The S1 IS features a grand total of seven white balance settings including the default automatic mode. There's also a manual (custom) white balance option, which is created by aiming the camera at a white (or gray) subject and pressing the SET button. Automatic white balance appeared to work well outdoors and in fluorescent lighting, but as per previous Canon digital cameras less well in incandescent light, where it produced a strong orange color cast (though not as bad as some models!). It is advisable to switch to the tungsten preset (or set a custom WB) when shooting indoors.

Outdoor - Auto WB
Red -0.4%, Blue 0.2%
Fluorescent - Auto WB
Red -0.1%, Blue -0.1%
Incandescent - Auto WB
Red 4.3%, Blue -6.7%

Flash Performance

The built-in pop up flash unit has a specified range of 4.2 m at wide angle and 3.0 m at telephoto (when the ISO is set to 100). In use we found it to meter very well indeed, with most indoor flash shots perfectly exposed unless the subject was closer than around 0.8M, at which point some burning out of highlights occurred. The FUNC menu offers a Flash Exposure Compensation setting (-2.0 to +2.0), but the lack of an AF illuminator caused some focus problems shooting in very low light.

Skin tone - no color cast, very slight underexposure Color chart - good exposure, no color cast

Macro Focus

The S1 IS is unusual in not having a dedicated macro mode, but it's no slouch when it comes to close focusing. As usual the best macro performance is at the wide end of the zoom, though even at the extreme (380mm equivalent) end the S1 IS manages impressive results. As is to be expected, shooting macros at the wide end of the zoom produces a fair degree of distortion, but we've seen far worse on superzoom cameras. There is no measurable pincushion distortion at the tele end.

Wide macro - 54 x 40 mm coverage
38 px/mm (961 px/in)
Distortion: High
Corner softness: Low
Equiv. focal length: 38 mm
Telephoto macro - 91 x 68 mm coverage
22 px/mm (568 px/in)
Distortion: None
Corner softness: Low
Equiv. focal length: 380 mm

Barrel and Pincushion Distortion

The S1 IS exhibits remarkably low distortion given the huge focal length range - just over 1.2% barrel distortion at the wide end, and no measurable distortion at all at the full 380mm telephoto end. There is also no noticeable vignetting.

Barrel distortion - 1.2% at Wide angle
Equiv. focal length: 38 mm
Pincushion distortion - 0.0% at Telephoto
Equiv. focal length: 380 mm

Specific image quality issues

Generally image quality was good, if not perfect. The images are generally well exposed, well focused and pretty sharp. If viewed at 100% (actual pixels) they lack a certain 'bite', giving images a touch of the 'still video' look. Overall, given the huge lens and low price, performance was not too disappointing, and certainly good enough for pin-sharp prints at up to about 5x7 inches.

Purple fringing

Purple fringing does occur, but not as often as you might expect - even when shooting very contrasty scenes. In fact the only time we found it to occur was at the edge of the frame at the telephoto setting, and only then in areas where there was some overexposure. Not bad at all.

380 mm equiv., F4.5 380 mm equiv., F4.5

Focus errors

The S1 IS suffers from more than its fair share of focus errors, particularly at the long end of the zoom, at close distances and when shooting in low light (where an autofocus illuminator would be invaluable). The small screen makes judging whether the focus has hit the right spot difficult, and you soon learn to zoom in on the playback image in situations where the focus is likely to struggle.

380 mm equiv., F6.3