In automatic mode the PowerShot G3 does better in natural light or fluorescent light, under incandescent light there was a strong orange cast. The preset white balance settings are excellent and provide accurate white balance which is almost indistinguishable from manual white balance. An excellent performance, especially if you stick to the preset settings.
|Outdoors, Auto||Outdoors, Cloudy (or Sunny)||Outdoors, Manual|
|Incandescent, Auto||Incandescent, Incandescent||Incandescent, Manual|
|Fluorescent, Auto||Fluorescent, Fluorescent (or H)||Fluorescent, Manual|
The G3's new lens provides the best macro frame coverage when set to wide angle. Obviously the disadvantage of this (especially at such short subject distances) is that there will be fairly significant barrel distortion and softness at the corners. Closest possible horizontal frame coverage was approximately 7.0 cm (2.8 in). You can improve things notably by using the optional Canon 250D Close-up lens.
The G3's new slim flash unit has a rated range (at ISO 100) of 0.7 - 5.0 m (2.3 - 16.4 ft) (at wide angle) and 0.7 - 4.0 m (2.3 - 13.1 ft) (at telephoto). Results appeared to be fairly good at moderate distances, no color cast, even illumination and good metering / power output.
|Skin tone - Good exposure, no color cast, natural skin color||Color patches - Good color balance, good flash power, good exposure|
Flash sync setting
New to the G3 is the ability to manually enable / disable slow-sync mode independently of flash mode and also choose 1st or 2nd-curtain sync. The word 'curtain' is comes from 35 mm shutter systems, 1st-curtain sync means that the flash fires at the beginning of the exposure, 2nd-curtain sync means that the flash fires just momentarily before the end of the exposure. Thus combined with a slow sync shot and some movement the use of 1st or 2nd-curtain sync can control the way that light trails are captured.
In the sample shots below the camera was mounted on a tripod and rotated clockwise around the vertical axis (from left to right).
|1st-curtain sync, flash fires at the beginning of the exposure, slow-sync trails continue to the right||2nd-curtain sync, flash fires at the end of the exposure, slow-sync trails start on the left|
The G3'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 to produce a clean noise free shot (as seen below). The G3 worked well even up to its maximum long exposure of 15 seconds.
|Manual exposure: ISO 50, 4 sec, F5.0||Manual exposure: ISO 50, 13 sec, F8.0|
Low Light Focus
This test measures the minimum amount of light under which the camera can still focus. The focus target is our lens distortion test chart (shown here on the right), camera is positioned exactly 2 m (6.6 ft) away.
Light levels are gradually dropped until the camera can no longer focus. This is carried out at both wide angle and telephoto zoom positions (as more light reaches the focusing systems with a larger aperture).
This test target is the optimum type of subject for most "contrast detect" AF systems (as it has a vertical line at its center), you should consider the results below the best you could expect to achieve.
|Lens position||Aperture||Lowest light focus|
|Wide angle (35 mm)||F2.0||Complete darkness|
|Telephoto (140 mm)||F3.0||Complete darkness|
Light intensity (Lux) = 2.5 x 2^EV (@ ISO 100), 10.76391 Lux = 1 foot-candle (fc)
The G3's AF assist lamp worked as expected at both wide angle and full telephoto. It illuminated the target sufficiently for the AF system to lock and produce a good focus.
Barrel and Pincushion Distortion
The G3's new four times optical zoom lens has an effective focal length range of 35 to 140 mm. 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). So overall the G3's four times optical zoom lens did exhibit some distortion (no distortion is virtually impossible with such small lens systems) but not enough to be of concern and less than most of the competition.
|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. As you can see below the G3 exhibits very little corner vignetting / light fall of, there is just the hint of it most visible in the top left corner but it's unlikely you would see this in a normal shot.