Canon PowerShot G5 Review
Being based around an unchanged G3 engine the G5 performs identically to that camera. Good automatic white balance in natural light, a strong orange cast in incandescent and fluorescent light. The preset incandescent white balance worked well, fluorescent less so. Manual white balance will of course deliver the most accurate and consistent color balance.
|Outdoors, Auto||Outdoors, Cloudy (or Sunny)||Outdoors, Manual|
|Incandescent, Auto||Incandescent, Incandescent||Incandescent, Manual|
|Fluorescent, Auto||Fluorescent, Fluorescent (or H)||Fluorescent, Manual|
The G5's best macro frame coverage (smallest possible area across the entire frame) was 55 mm (2.2 in) at full telephoto (140 mm equiv.). The good thing about this is that you won't see any barrel distortion. (Footnote: In our G3 review we incorrectly measured the best frame coverage at wide angle, in actual fact telephoto macro is considerably better).
The G5's internal flash unit has a specified range of 5.0 m (16.4 ft) at wide angle) and 4.0 m (13.1 ft) at telephoto. No color cast, slightly underexposed.
|Skin tone - Natural color, no blue cast, slightly underexposed.||Color patches - Good color balance, no color cast, slightly underexposed.|
The G5's automatic noise reduction system kicks in for exposures of 1.3 seconds or slower. It uses a 'dark frame subtraction' method which entails taking 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 G5 (and its five megapixel sensor) wasn't anywhere near as happy as the G3 with night exposures, 'hot pixels' and dark pits were visible in exposures longer than about 10 seconds.
|Manual exposure: ISO 50, 8 sec, F2.8|
|Manual exposure: ISO 50, 15 sec, F4.0|
Barrel and Pincushion Distortion
No surprises here, the same lens as the G3, the same result. At the wide angle end the lens exhibited approximately 0.9% barrel distortion (below average) and 0.4% pincushion distortion at telephoto (below average for a 4x lens).
|Barrel Distortion, 0.9% @ wide angle||Pincushion Distortion, 0.4% @ telephoto|
Vignetting / Light fall off
Our vignetting / light fall off test is very simple, a
shot of a blank wall from two meters away, vignetting will always be most
visible at wide angle and maximum aperture and will start to disappear
at smaller apertures and/or further zoom. The G5 exhibits a little vignetting
and light fall-off, most visible in the bottom left and right corners
of the frame. It's unlikely this amount of light fall-off would be visible
in everyday shots.
|Slight corner vignetting visible at wide angle and maximum aperture (F2.0)||No noticeable vignetting at telephoto (F3.0)|
Purple Fringing (Chromatic Aberrations)
We expected pretty much the same performance as the G3 (some purple fringing but not enough to be of real concern). However the G5 does appear to exhibit stronger fringing with a larger border and even at smaller apertures (where fringing typically disappears). Could this be because of the tighter pitch of the microlenses on the CCD? (pure speculation). As you can see from the samples below while fringing is reduced at higher apertures it is still visible. For me this level of fringing isn't really acceptable in a modern digital camera.
|Fringing visible around reflective highlights, F4.0||Fringing visible in areas of contrast, F4.0|
|Our standard chromatic aberration test shot|
Foil "torture test"
|F2.5 - Fringing clearly visible||F4.5 - Fringing still visible although reduced|
Overall Image Quality / Specific Issues
I'm sure the production of the G5 was a 'no brainer' for Canon, simply slot in the new five megapixel 1/1.8" CCD in the place of the G3's four megapixel 1/1.8" CCD and just to spice things up a little turn the body black. Well, I'm sure it wasn't quite as simple as that but this is essentially what we have. From an image quality point of view the G5 has all the positive aspects which the G3 brought, good dynamic range, optimum resolution, natural tone balance, strong yet accurate color and clean ISO 50 images. The G5 continues one tradition of Canon's 'G' range, and that is producing as much resolution as we could expect from the sensor used, in this case the G5 delivering as much detail as we have seen from this 1/1.8" CCD.
There were obvious compromises in making that jump from four to five megapixels, noise has increased from ISO 100 upwards, indeed the G5 is looking noisier than a lot of the competition. Purple fringing is also worse, both at maximum aperture and stopped down, which wasn't something we were expecting.
Shallow angle jaggies
Something we picked up in our G3 review is still here with the G5. 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.