Canon G11 Exposure
Canon PowerShot G11 Exposure
Saturation & Hue Accuracy
Good overall color and hue accuracy, with moderate oversaturation of some colors.
Saturation. The Canon G11 produced good saturation overall, with moderate oversaturation in reds, greens and blues. Some other colors such as bright yellows and cyans were actually undersaturated a small amount. Overall, the Canon G11's images appeared to have natural looking color that wasn't too vivid, but you can always adjust saturation to your liking. Most consumer digital cameras produce color that's more highly saturated (more intense) than found in the original subjects. This is simply because most people like their color a bit brighter than life.
Skin tones. Here, with the color balanced properly for the light source, the Canon G11's skin tones did have a slightly reddish cast, but should still be pleasing to most consumers. Where oversaturation is most problematic is on Caucasian skin tones, as it's very easy for these "memory colors" to be seen as too bright, too pink, too yellow, etc.
Hue. The Canon PowerShot G11 produced a few color shifts relative to the correct mathematical translation of colors in its subjects, most visibly pushing cyan way towards blue (for better-looking skies), red toward orange, and yellow toward green. The yellow toward green shift is particularly evident in the yellow yarn of our Still Life test shots, and is a problem we're now seeing in cameras from multiple manufacturers. While the G11's yellows do have a slightly greenish hue, though, it does manage to maintain good separation among hues as you progress from yellow to red. Still, despite the shifts in orange through yellow and cyans, overall hue accuracy was pretty good. Hue is "what color" the
The Canon G11 lets you adjust the image Saturation, Contrast, and Sharpness (as well as Red, Green, Blue, and Skin Tone settings) in five steps each. As can be seen below, the saturation adjustment was pretty effective. It also leaves the image contrast relatively unaffected, which is as it should be.
|Saturation Adjustment Examples
The table above shows results with the default as well as the two "extreme" saturation settings. Click on any thumbnail above, then click again to see the full-sized image.
| See full set of test images
See thumbnails of all test and gallery images
Exposure and White Balance
Indoors, incandescent lighting
Good color with both Auto and Manual white balance settings. About average positive exposure compensation required.
|Auto White Balance
|Incandescent White Balance
|Manual White Balance
Color balance indoors under incandescent lighting had a slight magenta cast with the Auto white balance setting, but the Canon G11 did better here than the majority of digital cameras we test. The Incandescent white balance option resulted in a fairly strong reddish cast, while the Manual setting produced the most accurate color overall. (Some users may actually prefer the slight warmth the Auto setting produced, as being more representative of the original lighting.) The G11's exposure system handled this lighting well, producing good results with an average amount of exposure compensation, + 0.3 EV. Overall color looks good, though the blue flowers look a touch purplish, probably due to the G11's tendency to punch up reds a little. (Many digital cameras reproduce the blue flowers here with more of a purplish tint, so the Canon G11 actually performs a good bit better than average here.) Our test lighting for this shot is a mixture of 60 and 100 watt household incandescent bulbs, a pretty yellow light source, but a very common one in typical home settings here in the U.S.
Good overall performance outdoors, though high contrast and hot highlights. Good color as well.
|Manual White Balance,
|Auto White Balance,
The Canon PowerShot G11 performed reasonably well under harsh outdoor lighting, though contrast was quite high. Slightly higher than average exposure compensation (+1.0 EV) was needed to keep the model's facial skin tones bright, resulting in a lot of blown highlights in her shirt and flowers. There was slight overexposure in the outdoor far-field house shot at the default exposure. Overall color is good though, if slightly reddish, with the Manual white balance setting on the portrait (the Auto and Daylight settings were just a touch too cool). Though overall contrast is high, the shadows hold onto a fair amount of detail. Fortunately, there's a contrast adjustment to help tame the highlights a bit, though it works better at bringing out shadows.
High resolution, 1,400 ~ 1,500 lines of strong detail from JPEGs, 1,600 from converted RAW files.
|Strong detail to
1,500 lines horizontal
|Strong detail to
1,400 lines vertical
|Strong detail to
1,600 lines horizontal
RAW via ACR
|Strong detail to
1,600 lines vertical
RAW via ACR
Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,500 lines per picture height in the horizontal direction, and 1,400 lines per picture height in the vertical direction. (Some might argue for over 1,800 lines, but artifacts begin to appear at much lower resolutions.) Extinction of the pattern occurred between 2,200 and 2,400 lines. We were able to extract a bit more resolution from Adobe Camera Raw 5.5 converted RAW files, about 1,600 lines both horizontally and vertically. Use these numbers to compare with other cameras of similar resolution, or use them to see just what higher resolution can mean in terms of potential detail.
Sharpness & Detail
Sharp, detailed images overall, with only minor edge-enhancement on high-contrast subjects. Noise suppression limits definition in low contrast areas, even at relatively low ISO settings.
|Good definition of high-contrast
elements, with only minor
|Subtle detail: Hair
Noise suppression blurs
detail in areas of subtle contrast,
as in the darker parts of hair here.
Sharpness. The Canon PowerShot G11 captures very good detail and reasonably sharp JPEG images. Slight enhancement artifacts are visible on high-contrast subjects such as the crop above left. Edge enhancement creates the illusion of sharpness by enhancing colors and tones right at the edge of a rapid transition in color or tone.
Detail. The crop above right shows moderate noise suppression, as the low contrast areas of hair show less distinct detail. Many individual strands remain fairly well defined, but the PowerShot G11's handling of subtle detail at low ISOs isn't notably improved over that of the earlier G10, despite its larger sensor pixels. Noise-suppression systems in digital cameras tend to flatten-out detail in areas of subtle contrast. The effects can often be seen in shots of human hair, where the individual strands are lost and an almost "watercolor" look appears.
RAW vs In-Camera JPEGs
As noted above, the Canon G11 produces fairly sharp, detailed in-camera JPEGs. We saw quite a bit more detail on the strongly contrasting geometric patterns of our resolution target when we converted images from RAW files using Adobe's Camera Raw plugin for Photoshop. In the natural image below, though, processing from RAW brought relatively little improvement in visible detail. Take a look below, to see what we mean:
In the table above, mousing over a link at the bottom will load the corresponding crop in the area above, and clicking on the link will load the full resolution image. Canon's Digital Photo Professional (version 126.96.36.199) software was able to extract slightly more detail, as was Adobe Camera Raw 5.5, though they both produced more sharpening artifacts than the camera's default settings, and neither resulted in the sort of dramatic improvement we see with some cameras. For ACR converted RAW files, we found that Canon G11 files required strong but tight sharpening. We used Photoshop to sharpen, with USM of 500% and Radius of 0.3 pixels.
ISO & Noise Performance
Low noise at the normal sensitivity settings, with pretty good results up to ISO 400. Strong noise and loss of detail at higher settings, however.
The Canon PowerShot G11 produced low to moderate noise at the lower sensitivity settings, though the effects of noise reduction such as smudging and loss of fine detail can already be seen even at the lowest ISO. Fine detail holds pretty strong up to ISO 200, though. At ISO 400, noise is still reasonable and a lot of fine detail remains intact, but additional smudging is evident. Noise grain isn't really more apparent as you move to ISO 800, but stronger noise reduction results in additional detail loss. Yellow and purple blotches (chroma noise) begin to appear in darker tones and hair at ISO 800, and worsen as ISO goes up. At ISOs 1,600 and 3,200, artifacts from noise reduction and increased chroma noise dominate, blurring out most fine detail. On-screen crops like this tell you only part of the story with a camera, though: To see how these images held up when printing at various sizes, read the Output Quality section below.
Many readers will no doubt be curious how the 10-megapixel G11 compares to its predecessor, the 14.7-megapixel G10, as well as to Panasonic's 10-megapixel LX3. See the crops and graph below. (Also see our Canon G11 JPEG Image Quality and Canon G11 RAW Image Quality pages for expanded comparison crops from our Still Life shot.)
As you can see from the crops above, the Canon G11 does offer noticeably lower noise levels relative to the previous G10, capturing a bit more detail with slightly fewer noise reduction artifacts. The Panasonic LX3 applies less noise reduction than either of the Canons, and while its images are noisier, they also hold more detail at higher ISOs, at least in these on-screen views. (Note that, unlike the other two, the G10 does not provide full resolution at ISO 3200.)
One thing that's very clearly going on here is that the LX3 is applying much more in-camera sharpening to its images than does the Canon G11. This both increases apparent detail and emphasizes noise. Let's take a look at what happens when we sharpen the G11's images to a roughly equivalent level:
ISO 1,600 Camera JPEG,
Unsharp Masked 270%, 1.0 pixel radius
ISO 1,600 Camera JPEG
The Canon PowerShot G11's high-iso images take quite a lot of sharpening, at a fairly large radius, to match the appearance of the LX3's files. At 270% and a 1 pixel radius in Adobe Photoshop, the G11 crop above now shows arguably better detail than the LX3, but with considerably finer-grained image noise.
This result was borne out by our printed tests. See the Print Quality section below for the details, but we found the Canon G11's high-ISO images straight from the camera very soft. Applying strong, large-radius sharpening to its ISO 1,600 images made for really surprisingly good prints at 8x10 inches, though. On that basis, the Canon G11's printed output was vastly better than that of the earlier G10, and in our view also significantly edged out the LX3 as well. (It's worth repeating here that it's virtually impossible to judge print quality with any reliability without studying actual prints: Images that look horrible on-screen 1:1 often appear just fine when printed at 8x10 or below. Likewise, other images may look pretty good on-screen, but display glaring flaws in print. As always, we encourage our readers to download our test images (for their own personal use), and print them out themselves, to obtain a true sense of each camera's image quality.)
The crops above are from images shot under incandescent lighting, a particularly difficult light source for achieving low noise images at high ISOs. Let's see how detail compares under simulated daylight:
The story is similar under simulated daylight. The Canon PowerShot G11 has a noticeable noise advantage over both the G10 and Panasonic LX3 at higher ISOs, but the Panasonic LX3 shows more visible detail in its camera-generated JPEGs. Sharpening the G11's images to overcome the softness of the original camera JPEGs brings its noise levels way up, but the noise is also very fine-grained, so modest-sized prints (8x10 inches at ISO 1,600, 5x7 inches at ISO 3,200) end up looking very nice.
ISO 1,600 Camera JPEG
ISO 1,600 Camera JPEG,
Unsharp Masked 200%, 1.0 pixel radius
ISO 1,600 Camera JPEG
The crops above show a different part of the image, to reveal both fine detail and shadow noise. The softness of the Canon G11's unaltered JPEG images at ISO 1,600 is quite evident in the leftmost crop. The center crop shows better fine detail than the LX3, yet noise levels are somewhat lower. We wouldn't use nearly this much sharpening for an image viewed solely on-screen, but when printed at ~8x10 inches, the results are really excellent.
A nice feature of the LX3 is adjustable NR, so you can make the trade-off between noise and detail yourself. The shots above were all captured with the LX3's default noise reduction setting. When we tested the LX3, we shot a noise reduction series (showing results from all available settings) at ISO 800; feeling that that was about its limit for reasonable-sized prints.
If you want to control the noise/detail/sharpness trade-offs with the Canon G11 or G10, you'll ultimately need to work from its RAW files using software. (Which does give you a lot more control than any in-camera settings, albeit with the added work of using RAW conversion software.) As seen above, though, you actually have a fair range of choice in that trade-off, simply by choosing how much post-capture sharpening you want to apply to its JPEG files.
(As mentioned above, also see our Canon G11 JPEG Image Quality and Canon G11 RAW Image Quality pages for expanded comparison crops from our Still Life shot. And definitely refer to our Print Quality section below, because image noise and detail can appear very differently in printed results than when viewed 1:1 on-screen.)
The plot above shows how the three cameras discussed above compare in terms of luminance noise across their full-resolution ISO ranges in daylight-balanced lighting, as reported by Imatest. As you can see, noise levels from the 10MP G11 are a good bit lower than those of the G10 across the board (not surprising, since the G10 has a 14.7MP sensor with smaller photosites). The LX3 is also 10MP and has similar noise levels up to ISO 400. At higher ISOs, the LX3 shows much higher noise, but also more detail.
Extremes: Sunlit and low light tests
High resolution with strong detail, but high contrast. Very good low-light performance, capable of getting bright images in near darkness.
Sunlight. The Canon PowerShot G11 performed reasonably well under the deliberately harsh lighting in the test above, but with washed-out highlights and deep shadows. Despite some noise suppression in the shadow areas, detail is still good in the shadows. Highlight detail is compromised, with clipping occurring in the shirt and some flowers. At +0.7 EV, the face, background and some shadow areas are just a little dark, so we preferred the +1.0 EV exposure, though it resulted in a lot of blown highlights. The G11's adjustable contrast setting did a good job of decreasing the overall contrast and bringing up the shadows and midtones, without creating any strange color gradations on the face. Be sure to use fill flash in situations like the one shown above; and it's better to shoot in the shade when possible.
As mentioned previously, the camera's contrast adjustment helped in handling dark shadows, but was less effective with strong highlights.
|Contrast set to lowest,
|Contrast set to lowest,
At its lowest contrast setting, the Canon G11 did a better job of holding more detail in the shadows while maintaining fairly natural-looking skin tones in the portrait shot above. It did not help much with the blown highlights in the far-field house shot, though shadow detail is better.
|Contrast Adjustment Examples
The shots above show the results of the minimum, default and maximum contrast settings. While you can see the extremes, it's pretty hard to evaluate small differences in contrast on small thumbnails like these, click on any thumbnail to go to the full-size image.
The above images show the effect of the Canon G11's Intelligent Contrast (i-Contrast) feature. The Auto mode did brighten the model's face quite a bit, though there appears to be sightly more clipping of highlights in her shirt and flowers. Still, pretty good results here.
|Face Detection Example
|Off, 0 EV
|On, 0 EV
The above images show the effect of the Canon G11's face detection autofocus mode (Face AiAF), which also adjusts exposure and white balance to optimize exposure for faces. The G11's face detection AF mode did adjust exposure so that the model's face is much brighter than with it Off, but as a result the rest of the scene became a bit too bright overall, losing a lot of detail in the highlights. Still, a handy feature, if you're dealing with strong backlighting, etc.
Because digital cameras are more like slide film than negative film (in that they tend to have a more limited tonal range), we test them in the harshest situations to see how they handle scenes with bright highlights and dark shadows, as well as what kind of sensitivity they have in low light. The shot above is designed to mimic the very harsh, contrasty effect of direct noonday sunlight, a very tough challenge for most digital cameras. (You can read details of this test here.)
Low light. The Canon PowerShot G11 performed well on the low-light test, capturing reasonably bright images at the lowest light level all the way down to ISO 200, close to the lowest sensitivity setting. At ISOs 80 and 100, the images at 1/16 foot-candle are a bit dim, due to the G11's maximum exposure time of 15 seconds (reported in the EXIF file header as 16s), but still usable. Color balance was pretty good with the Auto white balance setting. Images were reasonably clean up to ISO 400 at the lowest light levels, but naturally, noise increases along with. In addition to applying high ISO noise reduction by default, the G11 automatically applies dark-frame subtraction for exposures 1.3 seconds or slower.
The camera's autofocus system worked well also, as it was able to focus on the subject down to about the 1/8 foot-candle light level unassisted, and in complete darkness with the AF assist enabled. (A useful trick when shooting under dim lighting is to just prop the camera on a convenient surface, and use its self-timer to release the shutter. This avoids any jiggling from your finger pressing the shutter button, and can work quite well when you don't have a tripod handy. With its ability to focus in very dim lighting, the G11 should do quite well in such situations.)
How bright is this? The one foot-candle light level that this test begins at roughly corresponds to the brightness of typical city street-lighting at night. Cameras performing well at that level should be able to snap good-looking photos of street-lit scenes.
NOTE: This low light test is conducted with a stationary subject, and the camera mounted on a sturdy tripod. Most digital cameras will fail miserably when faced with a moving subject in dim lighting. (For example, a child's ballet recital or a holiday pageant in a gymnasium.) For such applications, you may have better luck with a digital SLR camera, but even there, you'll likely need to set the focus manually. For information and reviews on digital SLRs, refer to our SLR review index page.
Coverage and Range
A powerful flash, with somewhat uneven coverage at wide-angle. About average exposure compensation required.
|Normal Flash, +0.7 EV
|Slow-Sync Flash, +1.0 EV
Coverage and Exposure. Flash coverage was somewhat uneven at wide-angle (not surprising, given the wider-than-average 28mm equivalent focal length), with more uniform results at full telephoto. In the Indoor test, the G11's flash underexposed our subject at its default setting, requiring a boost in exposure to +0.7 EV, a typical value for this scene. The camera's Slow-Sync flash mode produced slightly dim results at the default exposure, so we chose +1.0 EV for the best exposure, though it has a strong yellow-orange cast from the room lighting.
ISO 100 Range. At wide-angle and ISO 100, flash shots gradually lost intensity as distance increased, but were still reasonably bright all the way out to 16 feet, the limit of our test. At telephoto, flash shots were fairly bright to about 9 feet, decreasing in brightness from that point on. Excellent results here.
|Manufacturer-Specified Flash Range
Auto ISO 500
Auto ISO 500
Manufacturer Specified Flash Test. In the shots above, the Canon G11 performs as Canon says it will at full wide-angle and telephoto, however it boosted sensitivity by quite a bit to ISO 500 to achieve these results. Our standard test method for flash range uses a fixed setting of ISO 100, to provide a fair basis of comparison between cameras. We've now also begun shooting two shots using the manufacturer-specified camera settings, at the range the company claims for the camera, to assess the validity of the specific claims.
Good print quality, good color, sharp 13x19-inch prints. ISO 400 images are soft but usable at 13x19, ISO 800 shots are usable at 11x14, and ISO 1,600 shots are usable at 5x7.
Output quality takes a noticeable drop at ISO 1,600, though, with prints looking really soft at Letter size (8.5 x 11 inches). Comparing shots from the Canon G11 with those from the Panasonic LX3, we discovered just how the LX3 gets such impressive printed results at this ISO setting. The LX3's high-ISO shots actually look pretty bad on-screen, with quite a bit of noise and very coarse-looking details. Printed, though, they look surprisingly good. What became apparent as we studied images from the two competing cameras was that the LX3's files had a lot of pretty large-radius sharpening applied to them. On-screen, they look really over-sharpened, but printed at 8x10 inches or so, they looked quite good. Applying similar over-sharpening to the Canon G11's images (1.0 pixel radius, 220%) produces similar-looking results on-screen, but excellent results on the prints as well, producing great-looking Letter size prints that actually edged out those from the LX3. With no processing, the Canon G11's ISO 1,600 images make acceptable-looking 5x7 inch prints.
This trick of deliberate over-sharpening turned out to be an important discovery, because performing the same trick on the G10's 14-megapixel images didn't produce anything like the same results, revealing much more chroma noise. The LX3's images likewise show some pretty distinct blotchiness that ends up more noticeable primarily because the LX3's saturation is also boosted a bit relative to that of the G11. While we seldom do this deep an analysis of print quality, it was an interesting exercise that showed how different sharpening strategies can get very different results. Because Canon's main reason for dropping the G11's resolution was to get better high ISO performance, we felt it was worth investigating why it its ISO 1,600 shots seemed so little improved when printed. This sort of issue often comes down to a matter of personal preference, but we think most G11 owners will be happier with their ISO 1,600 photos if they take the time to "oversharpen" them.
Leaving ISO 1,600 aside, it's worth noting that the ability to print ISO 800 images at 11x14 with only minimal softness is quite an accomplishment for a compact camera, particularly when you consider how much smaller the Canon G11's sensor is compared to those of APS-C cameras like the Canon Rebel XS or XSi.
Testing hundreds of digital cameras, we've found that you can only tell just so much about a camera's image quality by viewing its images on-screen. Ultimately, there's no substitute for printing a lot of images and examining them closely. For this reason, we now routinely print sample images from the cameras we test on our Canon Pro9000 Mark II studio printer, and on the Canon Pixma MP610 here in the office. (See the Canon Pixma Pro9000 Mark II review for details on that model.)
The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Canon PowerShot G11 Photo Gallery .
Not sure which camera to buy? Let your eyes be the ultimate judge! Visit our Comparometer(tm) to compare images from the Canon PowerShot G11 with those from other cameras you may be considering. The proof is in the pictures, so let your own eyes decide which you like best!