Canon PowerShot G6 Review
In natural and fluorescent light the G6's automatic white balance appears to work well with no visible color cast. The story under incandescent light however is all too familiar, a strong pink cast which leaves the image in a state which would be very difficult to correct. It's clear that in this respect at least the G6 doesn't improve on the G5. I'd be really pleased to see Canon making some advance on this subject, unfortunately another model and no improvement.
|Outdoor - Auto WB
Red -0.5%, Blue -0.1%
|Fluorescent - Auto WB
Red -1.3%, Blue -0.5%
|Incandescent - Auto WB
Red 7.7%, Blue -11.0%
The G6's built-in flash unit has a specified range of 5.0 m at wide angle and 4.0 m at telephoto (both at ISO 100), that's quite a bit more powerful than the average compact camera flash. The results from our flash test proved good, the color chart came out with good balance and no color cast, the skin tone test looking natural and not fooled by the white background.
|Color chart - good exposure, no color cast||Skin tone - no color cast, slightly over exposed|
The G6 has automatic noise reduction which kicks in for exposures of 1.3 seconds or slower. It uses a 'dark frame subtraction' method which takes a second equally long exposure after the main shot (thus an 8 second exposure will take 16 seconds). This dark frame contains a similar noise pattern to the original shot and can be used to 'subtract' hot pixels from the final image. The G6 appears to perform noticeably better than the G5 did, almost no visible hot pixels or dark pits (a consequence of dark frame subtraction NR) visible even in quite long exposures.
|ISO 50, 8 sec, F4.0 (manual exposure)|
|ISO 50, 15 sec, F5.6 (manual exposure)|
The G6's best macro performance (best frame coverage) was achieved at full telephoto (140 mm equiv.) the lens also exhibits the least distortion at that position however at this magnification the corners of the frame are soft and there's even some lateral chromatic aberration.
Barrel and Pincushion Distortion
No real surprises for us with this test, the G6 has the same lens construction as the G5 and produces the same distortion values (although it's worth noting the 0.4 / 0.3% difference in the pincushion distortion value is down to our more accurate automated measuring system). For a 35 mm equiv. wide angle the 0.9% barrel distortion figure is about average, 0.3% pincushion distortion at telephoto is very good and will hardly ever be noticeable.
|Wide angle - 0.9% Barrel distortion
Equiv. focal length: 35 mm
|Telephoto - 0.3% Pincushion Distortion
Equiv. focal length: 140 mm
Vignetting / Lens Shading
Our vignetting measurement is made by taking the average luminance value of the darkest corner of the image and comparing it to the average luminance at the center of the image, any difference greater than 15% may be visible in everyday shots. The G6 produced fairly low fall off figures except at full wide angle and maximum aperture, although at 16% it's still borderline.
Purple Fringing (Chromatic Aberrations)
An area of weakness for the PowerShot G5 appears to have been resolved on the G6. While it is still possible to squeeze a little bit of purple fringing out of the G6 it's fair to say it performed much better than the G6 and indeed better than the average. Canon did go out of their way to note that the G6 lens while based on that of the G5 now features new coatings designed to cut-down on such effects.
|35 mm equiv, F2.0 (max aperture)|
|35 mm equiv., F3.2|
|35 mm equiv., F2.0 (max aperture)s|
Overall Image Quality / Specific Issues
Canon chose to skip the six megapixel CCD and instead jumped directly from the 1/1.8" five megapixel of the G5 to the 1/1.8" seven megapixel of the G6. Overall we'd say it's been a successful transition, the new CCD seems to be surprisingly good with not low but acceptable noise levels, usable dynamic range and good sharpness (less strong anti-alias filter?). Of course you need a lens to deliver the resolution back to the CCD and the G6's F2.0 - F3.0 appears to be more than capable of this task, better still because of its large maximum aperture most of the time it is stopped down (smaller apertures) which optimizes sharpness and resolution.
Shallow angle jaggies
An artifact we picked up on in our G3 and G5 reviews appears to be still a part of the G6's image processing. At very shallow angles (approximately ten degrees or less) in a strong contrast the camera's algorithms (either demosaic or sharpening) don't alias the diagonal line particularly well and it can end up looking slightly jagged. Although to be totally fair to the G6 we didn't find any solid examples of this artifact in 'everyday shots' (only the resolution chart shot).
|Chicago Alley by tko|
from Down the alleyway
|Callan-5680 by vbuhay|
from What Child's Dream May Come
|Widget by Wilfried HKG|
|Oxbow Bend by stickpointed|
from Landscape - Colour #2