Canon Powershot G6By: Dave Etchells
The next generation of Canon's popular "G" model updates the line with a larger, 7.1-megapixel CCD and a redesigned camera body.
<<Reference: Datasheet :(Previous) | (Next): G6 Imatest Results>>
G6 Sample ImagesReview First Posted: 09/28/2004
Digital Cameras - Canon PowerShot G6 Test Images
|I've begun including links in our reviews to a Thumber-generated index page for the test shots. The Thumber data includes a host of information on the images, including shutter speed, ISOsetting, compression setting, etc. Rather than clutter the page below with *all*that detail, we're posting the Thumber index so only those interested inthe information need wade through it!|
(This is my new "Outdoor" Portrait test - read more about it here.)
The extreme tonal range of this image makes it a tough shot for many digicams, which is precisely why I set it up this way, and why I shoot it with no fill flash or reflector to open the shadows. The object is to hold both highlight and shadow detail without producing a "flat" picture with muddy colors, and the G6 handled the challenge pretty well, though contrast is somewhat high, even with its contrast adjustment set to the "low" position.
The shot at right was taken with a +0.7 EV exposure compensation adjustment, which held onto the highlight detail, but at the cost of somewhat dark midtones and skin tones. I chose the Auto white balance as the most accurate overall, though results were similar to the Daylight setting. The Manual setting was a bit warm, however.
Overall color looks good, with very good skin tones. The blue flowers in the bouquet are a little darker and more purplish than in real life, but overall pretty close to the correct color. The red flowers are a bit oversaturated, but aren't too far out of range, and saturation looks pretty good in the strong greens and yellows. Color looks good throughout the rest of the frame as well, though the red flowers are just a tad oversaturated. Resolution is outstanding, as the G6's 7.1-megapixel CCD captures excellent detail throughout the frame, even in Marti's facial features. Detail is very good in the shadow areas as well, despite the high contrast, and image noise in the shadows is lower than I'm accustomed to seeing.
To view the entire exposure series from zero to +1.3 EV, see files G6OUTAP0.HTM
through G6OUTAP4.HTM on the thumbnail index page.
Outstanding resolution and detail, though again somewhat high contrast.
Color balance and exposure appear similar to the wider shot above, but again with slightly high contrast from the high-key lighting. Midtones are a hint dark, but still have a lot of strong detail. The shot at right was taken with no exposure compensation adjustment, which produces rather dark midtones, but I felt that the +0.3 EV setting resulted in too-strong highlights on Marti's face. The G6's 4x zoom lens helps prevent geometric distortion of Marti's features, and captures sharp details. Resolution is again excellent, with absolutely outstanding definition in the details of Marti's face and hair, as well as in the fabric texture of the green leaves.
To view the entire exposure series from zero to +1.3 EV, see files G6FACAP0.HTM
through G6FACAP4.HTM on the thumbnail index page.
Indoor Portrait, Flash:
Good intensity and coverage with both flash modes, with pretty good color, despite a slight orange cast.
The G6's built-in flash illuminated the subject pretty evenly at the default exposure setting, although it underexposed it a fair bit. I actually chose an exposure compensation adjustment of +1.0 EV for the main exposure, which is slightly high. Though coverage was fairly even at the lower exposures, the higher exposure produced a much brighter shot. Color balance is orange from the strong incandescent room lighting, though the orange cast isn't too strong. (Still, a good bit more than I like to see in this shot.) I also shot with the Slow Sync flash mode, choosing an exposure compensation adjustment of +0.7 EV for the main shot here. Results were similar to the normal flash mode, with about the same amount of orange cast from the background lighting.
To view the entire exposure series from zero to +1.3 EV in the normal flash mode, see files G6INFP0.HTM through G6INFP4.HTM on the thumbnail index page.
To view the same exposure
series in the Slow Sync flash mode, see files G6INFSP0.HTM through G6INFSP4.HTM
on the thumbnail index page.
Indoor Portrait, No Flash:
Trouble with automatic white balance, but good results with both Incandescent and Manual settings, good exposure as well.
This shot is always a very tough test of a camera's white balance capability, given the strong, yellowish color cast of the household incandescent bulbs used for the lighting. The G6's Incandescent white balance setting did the best job here, though results are just slightly cool and magenta overall. Still, overall color looked best, as the Manual setting resulted more a yellow cast than I like, and the Auto setting had a strong warm cast. (Like many other digicams, Canon's cameras seem to have quite a bit of difficulty with household incandescent lighting in Auto white balance mode.) The main shot was taken with a +1.0 EV exposure compensation adjustment, about average for this shot. The blue flowers in the bouquet are slightly dark and purplish, but actually look pretty good considering the difficult light source. There's a modest amount of image noise in these ISO 100 shots (the standard ISO that I shoot this subject at), but it doesn't detract from the subject detail too much, and isn't very visible unless you look specifically at the image's blue channel.
To view the entire exposure series from zero to +1.3 EV, see files G6INTP0.HTM
through G6INTP4.HTM on the thumbnail index page.
Excellent resolution and detail, with good color.
The G6's Auto and Daylight
white balance settings both produced similar results, with just slight
warm casts. The Manual produced a more accurate
white value in the house trim. Overall color is just slightly cool with
the Manual setting, and the green grass has a blue tint, but I chose it
for the main image, as I felt that it was the most natural looking. Resolution
is very high, as the G6's 7.1-megapixel CCD can actually capture more
detail than this poster has in it (even though the image was made from
a 500-megabyte scan of a 4x5 negative shot with a tack-sharp lens). Details
are also sharp throughout the frame, from corner to corner. A very good
Excellent resolution and detail, lost detail in the highlights, but very good shadow detail.
This image is shot at infinity to test far-field lens performance. NOTE that this image cannot be directly compared to the other "house" shot, which is a poster, shot in the studio. The rendering of detail in the poster will be very different than in this shot, and color values (and even the presence or absence of leaves on the trees!) will vary in this subject as the seasons progress. In general though, you can evaluate detail in the bricks, shingles and window detail, and in the tree branches against the sky. Compression artifacts are most likely to show in the trim along the edge of the roof, in the bricks, or in the relatively "flat" areas in the windows.
This is my ultimate "resolution shot," given the infinite range of detail in a natural scene like this, and the G6 does an outstanding job with it. The level of fine detail visible in the tree limbs over the roof and fine foliage in front of the house is exceptional, with crisp definition, even in the smallest leaf patterns. In-camera sharpening does a good job here, with good sharpness and relatively few artifacts of the sharpening process. The G6's lens does very well also, with good sharpness from corner to corner (just a little softness is visible in the two top corners).
The camera lost most of the detail in the bright
white paint surrounding the bay window, but held very good detail in the
shadow area above the front door, with low noise. Overall color and exposure
both look very good. The table below shows a standard resolution and quality
series, followed by ISO, sharpness, contrast, saturation, and color series.
Lens Zoom Range
A good 4x zoom range.
I routinely shoot this series of images to show the field of view for
each camera, with the lens at full wide angle, at maximum telephoto (4x,
in this case), and at full telephoto with the digital zoom enabled. The
G6's lens is equivalent to a 35-140mm zoom on a 35mm camera. That corresponds
to an average wide angle to a fairly substantial telephoto. Following
are the results at each zoom setting.
Good color and excellent detail.
This shot is often a tough test for digicams, as the abundance of blue
in the composition frequently tricks white balance systems into producing
a warm color balance. Both the G6's Auto and
Daylight settings both produced similar results, with only slightly
warm, color. The Manual setting also produced
nearly accurate color, but with a cooler cast. I chose the Auto setting
for the main image, as the skin tones looked best to my eye. The blue
robe looks just about right, with only faint purplish tints in the deep
shadows. Detail is very strong and resolution very high, with great clarity
in the embroidery of the blue robe, as well as in the flower garland,
beaded necklaces, and instrument strings. (The original data file for
this poster was only 20MB though, so cameras like the G6 are definitely
capable of showing more detail than the poster has in it.)
A small macro area with good detail in the dollar bill, but the corners are very soft. Flash almost throttles down enough, but overexposes slightly.
The G6 performed very well in the macro category, capturing a minimum
area of only 2.11 x 1.58 inches (54 x 40 millimeters). Resolution is very
high, showing a lot of fine detail in the dollar bill. The G6 loses some
points in the macro category though, for the very soft corners in the
image. Most digicams tend to have soft corners when shooting in macro
mode, but the G6 is worse in this respect than most. The G6's flash
almost throttles down for the macro area, but still overexposes a little
in its default exposure mode. Happily though, its built-in 3-stop neutral
density filter more than makes up the necessary difference.
"Davebox" Test Target
Good color and exposure.
The G6's Manual white balance setting produced
the best results here. The Auto white balance
setting also produced good results, though slightly yellow. The Daylight
setting resulted in a stronger warm cast. Exposure is about right, and
the G6 distinguishes the subtle tonal variations of the Q60 target without
any trouble. The large color blocks are accurate with good saturation
(only slight oversaturation in the red and blue primary color blocks).
Detail is strong in the shadow area of the charcoal briquettes, and the
last steps of the vertical gray scales are just visible. Image noise is
low. Good results overall.
Very good low-light performance, with bright images and good color to the limits of my test. Good focusing with the AF illuminator as well.
The G6 produced clear, bright, usable images with good color down to the 1/16 foot-candle (0.67 lux) limit of my test at all four ISO settings. (Average city street lighting at night corresponds to a light level of about 1 foot-candle.) Some of the shots at the lowest light levels show a slight pink cast, but overall color is still quite good. Noise was low, at the 50 and 100 ISO settings, creeping upward at ISO 200, and becoming high at ISO 400. Even at ISO 400 though, while the amplitude of the noise is fairly high, its pattern is so fine-grained that it really isn't all that objectionable. (IMHO, anyway - I'd have no qualms about shooting at ISO 400 with the G6.) Thanks to its bright autofocus-assist illuminator, the G6 can also focus in almost total darkness as well. The table below shows the best exposure I was able to obtain for each of a range of illumination levels. Images in this table (like all sample photos) are untouched, exactly as they came from the camera.
(Note: If you'd like to use a light meter to check light levels for subjects you might be interested in shooting, a light level of one foot-candle corresponds to a normal exposure of two seconds at f/2.8 and ISO 100.)
Flash Range Test
A powerful flash, with consistent results to the 14 foot limit of this test.
In my testing, the G6's flash illuminated the test target all the way out to 14 feet, without any significant decrease in intensity. Below is the flash range series, with distances from eight to 14 feet from the target.
Very high resolution, 1,550 lines of "strong detail." Average barrel distortion, and low pincushion.
The G6 performed very well on the "laboratory" resolution test chart. It didn't start showing artifacts in the test patterns until resolutions around 1,200 lines per picture height vertically, but around 1,000 lines horizontally. I found "strong detail" out to at least 1,550 lines horizontally, but only to about 1,500 lines vertically. (And there were strong aliasing artifacts a good 100-150 lines lower than these levels.) "Extinction" of the target patterns didn't occur until about 1,900 lines.
Using its "MTF 50" criteria, Imatest reported uncorrected resolution figures of 1552 line widths per picture height in the horizontal direction (corresponding to the vertically-oriented edge), and 1334 along the vertical axis (corresponding to the horizontally-oriented edge), for a combined average of 1443 LW/PH. Correcting to a "standardized" sharpening with a one-pixel radius increased the vertical number quite a bit, to 1493 LW/PH, giving a corrected average of 1523 LW/PH, an excellent result.
Optical distortion on the G6 is about average at the wide-angle end,
where I measured approximately 0.7 percent barrel distortion. The telephoto
end fared much better, as I measured approximately 0.3 percent pincushion
distortion there. (Both numbers are within the average range, among digicams
I test.) Chromatic aberration was very low, showing no more than two or
three pixels of moderate coloration on either side of the target lines.
(This distortion is visible as a very slight colored fringe around the
objects at the edges of the field of view on the resolution target.) The
G6's lens was also very sharp from corner to corner, further evidence
of high quality optics.
Resolution Series, ~50mm equivalent focal length
Resolution Test, Telephoto
Viewfinder Accuracy/Flash Uniformity
A very tight optical viewfinder, but accurate LCD monitor.
The G6's optical viewfinder is very tight at telephoto, showing approximately 76 of the final image area. Results were a little better at wide angle, showing about 83 percent frame accuracy. The LCD monitor proved more accurate, showing about 99 percent at both zoom settings (though my top measurement lines were cut off at the wide angle setting, possibly from the barrel distortion). Given that I like LCD monitors to be as close to 100 percent accuracy as possible, the G6's LCD monitor is essentially perfect in this regard, but I'd really like to see a more accurate optical viewfinder on the camera. Flash distribution was a little uneven at wide angle, with falloff at the corners and edges of the frame. At telephoto, flash distribution was more uniform, though some slight falloff is visible in the corners.
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