White Balance

The S3 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 not terribly in fluorescent lighting, but as per previous Canon digital cameras less well in incandescent light, where it produced a pronounced orange color cast (though it is perhaps not quite as strong). It is advisable to switch to the tungsten preset (or set a custom WB) when shooting indoors if you don't like a warm cast to your indoor shots.

Incandescent - Auto WB
Red 10.2%, Blue -13.4%
Incandescent - Incandescent preset WB
Red -1.4%, Blue 2.6%
Fluorescent - Auto WB
Red 1.4%, Blue -11.4%
Fluorescent - Fluorescent preset WB
Red 2.8%, Blue -4.7%

Flash Performance

The built-in pop-up flash unit has a specified range of 5.2 m at wide angle and 4.0 m at telephoto (when the ISO is set to auto). In use we found it to work very well indeed, with most indoor flash shots perfectly exposed. The FUNC menu offers a Flash Exposure Compensation setting (-2.0 to +2.0), and the AF illuminator helps focus in low light (though it isn't powerful enough for such a long zoom camera - it only really works over distances of about 1.3 m and lower).

Skin tone - Slight warm tone, excellent exposure Color chart -Slight warm tone, excellent exposure

Macro Focus

Macro performance is identical to the S2 IS; in other words nothing to write home about, despite the headline '0cm' Super Macro mode. First let's look at the standard macro mode, which allows you to get down as close as 10cm (at the wide end of the zoom). It's okay, but nothing special (fitting an area of around 11cm across into the frame). At the telephoto end of the zoom you can actually get slightly higher magnification (photographing an area of around 8.5cm across), with less distortion and less corner softness, albeit from a much greater distance (about 70cm).

Wide macro - 107 x 80 mm coverage
26 px/mm (665 px/in)
Distortion: Average
Corner softness: Average
Equiv. focal length: 36 mm
Telephoto macro - 85 x 64 mm coverage
33 px/mm (837 px/in)
Distortion: Low
Corner softness: Low
Equiv. focal length: 432 mm

Super Macro mode

If its normal macro mode is nothing to write home about, the S3 IS has the same rather unique trick up its sleeve as its predecessor - a 'super macro mode' that allows you to focus down to an unprecedented 0cm from the front element. This means it can actually focus on things that are touching the front of the lens. Of course there aren't many things you can actually photograph from 0cm - they either need to be lit from behind (you can use the S3 IS to shoot 35mm slides if you don't mind the cropping, distortion and corner softness!) or small enough that they don't fill the frame. In most cases the shadow of the lens obscures your subject so much that you can't use it at distances of less than a few centimetres, at which point the subect area you're photographing is around 40mm across - roughly the same as most of its competitors (such as the Panasonic FZ7), but with the ever-present danger that you'll move so close that you end up causing permanent damage to the front element of the lens. Still, it's fun to play with and does allow you to take some unique photographs.

Super macro - 21 x 16 mm coverage
124 px/mm (3142 px/in)
Distortion: High
Corner softness: Average
Equiv. focal length: 36 mm

Focus distance for this shot was 0cm (chart lit from behind).

Pirhana in resin, 0cm distance Inside of orchid, approx 0cm distance

Barrel and Pincushion Distortion

The S3 IS exhibits remarkably low distortion given the huge focal length range - 1.1% barrel distortion at the wide end, and no measurable distortion at all at the full 432mm telephoto end. There is also only barely measurable - and hardly noticeable - vignetting.

Barrel distortion - 1.1% at Wide angle
Equiv. focal length: 36 mm
Pincushion distortion - 0.0% at Telephoto
Equiv. focal length: 432 mm

Image stabilization

The optical image stabilization system used on the S3 IS (and its predecessor) works, and it works pretty well for most everyday photography - though don't expect miracles. There are three modes: Continuous (IS on all the time), 'Shoot only' (IS is activated at the moment the exposure is made) and Panning (for horizontally panned shots).

The first option makes framing easier - the IS system steadies the preview image, and we found it more consistently effective at extremes (where the shutter speed is more than 3 stops slower than would normally be used for the focal length you're shooting at) than the shoot only mode. Shoot only - which doesn't steady the preview image, but is theoretically more efficient because it minimizes the amount of corrective movement required by waiting until the instant the picture is taken - is perfectly effective when you're nearer to the correct shutter speed (and once you're within 1 or 2 stops it is actually more reliable). I wouldn't read too much into the fact that our results for the relative effectiveness of the two modes are the opposite to what we saw with the S2 IS; we have no quantitative tests for stabilzation, and every person's 'shake' is different; users often disagree on which mode works best, so you just have to find which best suits your style of shooting.

I certainly found it made handheld shots at 3, 4 or even 5 shutter speeds slower than normal perfectly possible. Impressive stuff (though the reliability is much better if you're within 3 stops), and if you take a couple of 'safety' shots when pushing the system hard (1/30th at 432mm for example), you'll usually get at least one 'keeper'.

Although we've no definitive test for IS systems in real-world use, I was very impressed with the S3's system, though I'm increasingly convinced that it isn't quite as effective as that used on Panasonic's Lumix range. Of course the more megapixels in the image, the more you're likely to see any blur (viewed at 100% on-screen); each new generation of 'super zoom' camera is pushing the system's capabilities that little bit more.

These tests are rather extreme - up to five stops slower than you could safely use without IS - and in 'real life' shots - where you are maybe using a shutter speed two stops slower than normal - the system is pretty much 100% effective.

IS off IS Continuous IS 'Shoot only'
1/15 sec, 36mm equiv. Macro
IS off IS Continuous IS 'Shoot only'
1/15 sec, 432mm equiv.
IS off IS Continuous IS 'Shoot only'
1/25 sec, 432mm equiv.
IS off IS Continuous IS 'Shoot only'
1/30 sec, 432mm equiv.

Specific image quality issues

Overall there is much to like here - color is excellent, bright and punchy without being unnatural, there's plenty of detail (though the same slight softness as the S1 and S2), and both focus and exposure are on the whole very reliable. As with most PowerShot cameras the key the the S3's appeal is that - despite the plethora of controls and image parameters on offer - it produces excellent, consistent results using the default settings, leaving you free to concentrate on the more imporant stuff, like actually taking the picture.

However there are a couple of qualifications to the last statement: firstly the best results by far are to be had at ISO 80 or 100; at ISO 200 the noise reduction, though effective, tends to smudge low contrast fine detail a bit too much for my liking, and ISO 400 and 800 produce results that look quite grainy (noise reduction software helps, and as mentioned elsewhere, Canon has at least resisted the temptation to use high NR in-camera, so there's still some detail there). Secondly the exposure system can be tricked by unusually contrasty scenes, usually resulting in mild overexposure, and blown highlights. The dynamic range seems to be slightly better than the S2 IS (the 5MP chip was notoriously fussy about exposure), so correctly exposed images don't show too much clipping, but you do sometimes find yourself reaching for the AE compensation when the metering gets it wrong; the live histogram is a real bonus here. Finally there is a noticeable fall off in sharpness if you use apertures more than about 2 stops in from the maximum (due to diffraction), and - as noted below - there is some mild chromatic abberation.

Purists may find the default output a little 'over the top', but most users will be pleased with the punchy contrast, saturation and sharpening - and there are lots of controls to play with (more than the S2 IS) if you like a more subtle or low-key output (if, for example, you like to post-process).

Purple fringing

Compared to the S2 IS we found purple fringing and chromatic abberations to be far less of a problem (due in part to the fact that during the entire test it was miserable and overcast). There is some CA visible at the long end of the zoom (red fringes) - common to most super zoom models, and you will get some purple fringing at the boundaries of very overexposed areas and dark areas, but I was pleasantly surprised to find it much less of a problem than we saw on the S2 IS.

100% crop 432mm equiv., F3.5