Purple Fringing (Chromatic Aberrations)
Pretty much the same performance as the G2, some slight fringing exhibited on our standard test shot, blue rather than strong magenta. It was possible to find fringing in very high contrast 'every day' shots but only in the corners of the frame. Not enough to be of any concern.
|Some fringing visible in the corners of shots with high contrast||Our standard chromatic aberration test shot|
Foil "torture test" comparison
There has been quite a bit of discussion on our Canon Talk forum about the visibility of chromatic aberrations on the G3 compared to the G2, according to reports from early adopters CA is more visible at wide open apertures (as expected) with pinpoint light. To test this we simply took the same shot of a ball of aluminium foil in direct sunlight. The shot was deliberately overexposed to attempt to produce chromatic aberrations. The test was applied to the PowerShot G3 and G2.
As you can see from the 100% image crops below both cameras exhibit some chromatic aberrations in these extreme situations, the G3's CA being more visible than the G2. Neither of these results however should be of any major concern, they are within the boundaries of what we would expect of such compact lens systems and are completely eliminated at apertures smaller than F2.8.
|PowerShot G3||PowerShot G2|
RAW vs. JPEG
One question we're often asked is what's the image quality advantage of RAW vs. JPEG. For digital SLR's the difference can be fairly major, especially when using some more advanced third party conversion tools. Our experience of prosumer level RAW conversion has always been mixed, yes it offers the perfect digital negative but often the RAW conversion software doesn't allow enough parameter change to affect much change.
Canon's new FileViewerUtility has a nice interface and is definitely an advance on previous RAW converts from Canon but for me it still doesn't (a) provide enough parameter change (only one level of change for things like saturation, tone and sharpness), (b) digital exposure compensation for G3 images, (c) output in different colour space or (d) any noticeable improvement in image quality.
As you can see from the samples below there's hardly any noticeable difference between the Super-Fine JPEG and RAW converted to TIFF (especially from tone, color or sharpness). Crops taken from TIFF, click to download a high quality JPEG output from FileViewerUtility.
Again, not much difference between RAW and JPEG, the same faint moiré artifacts, the same resolution performance. The only slight difference may be a slightly less visible sharpening halo around the black characters against the white background. Crops taken from TIFF, click to download a high quality JPEG output from FileViewerUtility.
Overall Image Quality / Specific Issues
The G3 was a logical evolution of the popular and no doubt successful G2, the new four times optical zoom lens appears to be of at least as good quality as the three times lens on the G2, and glass is always so important for compact digital cameras. The improved image processing algorithms have also taken care of a few 'niggles' with the G2, notably color moiré has been reduced and there's no trace of the forty five degree jagged diagonals we observed (although shallow diagonals on our resolution chart were still jagged).
G3 images exhibit great dynamic range, are normally well metered and have a natural tonal balance. The G3 has an uncanny ability to maintain highlight detail (especially in sky) while still delivering detailed and 'light' shadows (shadows which don't disappear into black too early). Noise levels are very good, especially at the ISO 50 setting (which is approximately equivalent to ISO 80).
Color is very 'PowerShot', that's to say the G3 has a very similar color response to all other recent PowerShot digital cameras, that's accurate yet vivid and pleasing to the eye. The camera never gets bogged down in mediocre lighting conditions which can sometimes throw out the color response of other cameras. Although it's difficult to verify Canon's claims about their new internal scene database the G3 does seem to 'know' what kind of shot you're attempting to take and could well be subtly tweaking tone and color response for each shot.
Overall the G3 delivers what must be considered the best image quality of any current four megapixel digital camera, from a detail, tonal balance and color response point of view. There's really very little about G3 images to criticize.
Shallow angle jaggies
Although we only observed this on our resolution chart it's worth noting because it may well be possible to reproduce in a normal 'every day' shot. At very shallow angles (approximately ten degrees or less) in a strong contrast the camera's algorithms (either de-mosaic or sharpening) don't alias the diagonal line particularly well and it can end up looking slightly jagged.