Digital Cameras - Canon PowerShot SD20 Digital ELPH 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, ISO setting, compression setting, etc. Rather than clutter the page below with *all* that detail, we're posting the Thumber index so only those interested in the information need wade through it! |
(This is my new "Outdoor" Portrait test - read more about it here.) High resolution and strong detail, with nearly accurate color, but contrast is high. 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 SD20 has a little trouble with the harsh lighting. The shot at right was taken with a +1.0 EV exposure compensation adjustment, which resulted in very hot highlights, with slightly dark midtones. (The shot with +0.7 EV of adjustment left Marti's skin tones too dark, while still losing highlight detail.) I also noticed some light falloff in the top corners of the frame, more than would be accounted for by the scene lighting. I chose the Auto white balance setting for the main series, though results were nearly identical to the Daylight shot. The Manual setting produced a warmer color balance, though results were still quite good. Marti's skin tones are good here (though perhaps a little strong in the pinks/reds), and the blue flowers in the bouquet look good as well. (Many digicams have trouble with this blue, and the SD20 very close to their correct color.) The strong red flowers have a hot pink tint, but the greens and yellows look about right. Resolution is very high, and detail is strong throughout the frame. Shadow detail is moderate, with low image noise. To view the entire exposure series from zero to +1.0 EV, see files SD20OUTAP0.HTM through SD20OUTAP3.HTM on the thumbnail index page. |
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Closer Portrait: Excellent resolution and detail, but high contrast once again. Strong distortion from the wide angle lens. Overall results are similar to the wider shot above, in terms of exposure and color, but the SD20's fixed 39mm lens results in strong geometric distortion of Marti's features. (The reason I originally included this shot in the test suite - Cameras with wide-angle, fixed focal length lenses just aren't suitable for closeup portraits.) The shot at right was taken with a +0.3 EV exposure compensation adjustment, much less than what was required in the larger portrait. Contrast is again high, and the highlights bright, with slightly dark midtones. Detail and resolution are much higher in this shot, with crisper details in Marti's face and hair. To view the entire exposure series from -0.3 to +1.0 EV, see files SD20FACAP0.HTM through SD20FACAP3.HTM on the thumbnail index page. |
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Indoor Portrait, Flash:
Low intensity at the default exposure, but good results with a heavy exposure boost. Slow-Sync mode performs well, though with a strong orange cast. The SD20's built-in flash illuminated proved quite dim at the default exposure setting, requiring a +1.0 EV exposure compensation boost to get the best exposure. Overall color looks good, though the background incandescent lighting results in an orange cast in the shadows and on the back wall. Color looks good in the flower bouquet, and skin tone is good as well (though slightly pink). I also shot with the camera's Slow-Sync flash mode, choosing a +0.7 EV exposure compensation adjustment. (The default exposure was again a little dim, but not bad.) Because the longer exposure allows more ambient light into the image, the orange cast is stronger. To view the entire exposure series from zero to +1.3 EV in the normal flash mode, see files SD20INFP0.HTM through SD20INFP4.HTM on the thumbnail index page. To view the same exposure series in the Slow-Sync flash mode, see files SD20INFSP0.HTM through SD20INFSP4.HTM on the thumbnail index page. |
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Indoor Portrait, No Flash:
Pretty good color with the Manual white balance setting, though low exposure. 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 SD20's Auto white balance setting fell victim to this trap, and produced a very warm image. The Incandescent and Manual settings produced much more accurate results, though the Incandescent setting had a slightly stronger red cast. Color balance is slightly pinkish with the Manual setting as well (mainly noticeable in the white shirt), but overall color still looks pretty good. The blue flowers in the bouquet are slightly dark and purplish, but still pretty good considering the difficult light source. The main shot was taken with a +1.0 EV exposure compensation adjustment, and image noise is moderately high. To view the entire exposure series from zero to +1.3 EV, see files SD20INMP0.HTM through SD20INMP4.HTM on the thumbnail index page. ISO Series:
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House Shot:
High resolution and detail, with great color. All three of the SD20's white balance settings performed well here, but I chose the Auto setting for the main image. I preferred its slightly warmer color to the cooler Manual white balance. The Daylight setting also produced very good results. Resolution is very high, and detail is strong in the house front, as well as in the shrubbery and tree limbs above the roof. Details are slightly soft throughout the frame, with increased softness in the corners. (There's also some light falloff in the corners of the frame.) |
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Far-Field Test Excellent resolution and detail, though a limited dynamic range and high exposure. 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 SD20 does indeed up a lot of detail. The foliage in front of the house, as well as the tree limbs above, show a lot of fine detail, with good definition. Details are slightly soft throughout the frame, but are still well-defined. Details do soften in the corners of the frame, and the exposure decreases, but the softness in the corners is less than I'm accustomed to seeing from many cameras. The camera loses almost all of the detail in the bright white paint surrounding the bay window, with is a difficult area for many digicams to contend with. Detail is slightly stronger in the shadow area above the front door, however. The table below shows a standard resolution and quality series, followed by ISO and Color Effects series. Resolution Series:
Color Effects Series:
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Lens Zoom Range A moderate wide angle fixed focal-length, and decreased resolution with the digital zoom. 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 (none, in this case), and at full telephoto with the digital zoom enabled. The SD20's fixed focal length lens is equivalent to a 39mm lens on a 35mm camera, which corresponds to a somewhat conservative wide angle. Following are the results at each zoom setting.
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Musicians Poster
Slightly warm color, but high resolution. 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. Though overall color is slightly warm, I preferred the more natural looking skin tones of the SD20's Auto white balance setting to the cooler, slightly magenta tone of the Manual white balance. (The Daylight setting was nearly identical to the Auto setting.) The blue background has a few purplish tints in it from the warm cast, as do the shadow areas of the blue robe. Resolution is very high, and fine detail is strong in the embroidery on the blue robe, as well as in the instrument, necklace, and flower garland details. (The original data file for this poster was only 20MB though, so cameras like the SD20 are definitely capable of showing more detail than the poster has in it.) |
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Macro Shot
An unusually tiny macro area with excellent detail. The SD20 performed very well in the macro category, capturing a minimum area of only 0.94 x 0.71 inches (24 x 18 millimeters). Resolution is excellent, and detail is very strong in the fibrous paper of the dollar bill. (The coin and brooch are soft due to the shallow depth of field resulting from the very short shooting distance, not the camera's fault.) Details are sharp and clear, but soften in the corners. The SD20's flash is ineffective at such a close shooting range, so I did not test it here. (Plan on using external lighting for your closest macro shots with the SD20.) |
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"Davebox" Test Target
Nearly accurate color, though low exposure. The SD20's Manual white balance setting did the best job here, though overall results are just slightly magenta. Still, I preferred the white value to the slightly warm Auto setting and the yellow Daylight setting. Exposure is just slightly low, but the SD20 does a good job with the subtle tonal variations of the Q60 target. Increasing the exposure compensation to +0.3 EV produces better results, without losing detail in the tonal variations. The SD20's color is very typically "Canon," somewhat oversaturating reds and blues, and pulling cyan colors more toward blue (which will tend to produce richer-looking sky colors in landscape photos.) Detail is moderate in the shadow area of the charcoal briquettes, with moderate noise. ISO Series:
Color Effects Series:
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Low-Light Tests Good low-light performance, with nearly accurate color. Moderately good low light focus performance. The SD20 produced clear, bright, usable images down to the 1/16 foot-candle (0.67 lux) limit of my test, with good color at the 200 and 400 ISO settings. At ISO 100, images were bright as far as 1/8 foot-candle (1.3 lux), but you could arguably use the image shot at the 1/16 foot-candle light level. At ISO 50, images were bright to about 1/4 foot-candle (2.7 lux), though the target was visible at the lower light levels as well. Noise is high at the ISO 400 setting, but the grain pattern is fine and tight, and the noise pixels aren't overly bright. The SD20 focuses moderately well in dim lighting, with the autofocus working down to about 1/2 foot-candle with out the AF-assist illuminator, and in complete darkness (on nearby objects) with the illuminator on. 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.) |
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Flash Range Test A bright flash to about 10 feet, then falloff from there.
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ISO-12233 (WG-18) Resolution Test Very high resolution, 1,400 lines of "strong detail" horizontally, 1,300 vertically. Slightly lower than average barrel distortion. The SD20 performed very well on the "laboratory" resolution test chart. It started showing artifacts in the test patterns at resolutions as low as 1,000 lines per picture height, in both horizontal and vertical directions. I found "strong detail" out to about 1,400 lines horizontally and 1,300 vertically. (Although that may be stretching things a bit in the vertical direction, as there are fairly heavy artifacts present, as low as 1,200 lines.) "Extinction" of the target patterns didn't occur until about 1,600 lines. Here's a sample image taken with the camera's Low Sharpening setting. Optical distortion on the SD20's 39mm fixed focal length lens is moderate, as I measured approximately 0.6 percent barrel distortion. (This is a bit lower than that of most zoom-equipped cameras at the wide angle end of their range, but still a bit higher than I'd like to see.) Chromatic aberration is very low, showing only about two or three pixels of very faint 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.) I also noticed that details softened a little toward the corners of the frame, and some light falloff was evident in the corners as well. Resolution Series, 50mm
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Viewfinder Accuracy/Flash Uniformity A pretty accurate LCD monitor. The SD20's LCD monitor was just a little loose, showing slightly more than what made it into the final frame. Still, results were very good, close to 100 percent accuracy. Flash distribution is a bit uneven, with falloff at the corners and edges of the frame. |
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