Canon PowerShot A20Canon's "value priced" 2 megapixel camera has 3x zoom, takes great pictures!<<Reference: Datasheet :(Previous) | (Next): Print-Friendly Review Version>> PowerShot A20 Test ImagesReview First Posted: 5/10/2001 |
| We've begun including links in our reviews to a Thumber-generated index page for our 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! ;) |
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Outdoor portrait: (879 k) The extreme tonal range of this image makes it a tough shot for many digicams, which is precisely why we set it up this way. The object is to hold highlight and shadow detail without producing a "flat" picture with muddy colors, and the Canon A20 does a very nice job. We shot samples of this image with the automatic (856 k) and daylight (885 k) white balance settings, which produced very similar results. We chose the daylight setting for our main series, as the overall color balance and skin tones were more accurate. (Skin tones in the automatic setting were just a little pale, although they are slightly magenta in the daylight setting.) The A20 tended to slightly overexpose this shot, albeit just a little. Most cameras require significant positive exposure compensation for this test, so the A20's metering was more accurate than most. Our main image was captured with a -0.3 exposure adjustment. Overall color looks pretty accurate. The blue flowers in the bouquet look about right, without any visible purple tints in the petals. (These blues are hard for many digicams to reproduce correctly, so the A20 performs much better than average in this respect.) Though the red flower is very bright, there is no halo effect around it, and it maintains good detail. Resolution seems pretty high, with a lot of fine detail visible in the image, particularly in the skin of the model's hand, in the flower bouquet, and in the model's face. The shadow areas show excellent detail, with very low noise. Overall, a really excellent performance from a value-priced digicam! The table below shows the results of a range of exposure settings from -0.3 to +1.0 EV. Exposure Compensation Settings:
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Closer portrait: (924 k) An excellent photo! The A20 again performs well with this closer, portrait shot, thanks to its 3x lens. (Shorter focal length lenses tend to distort facial features in close-up shots like this and the availability of longer focal lengths is a key feature if you're going to be shooting close-up people shots.) We again shot with the daylight white balance setting, which produced a good color balance, though slightly magenta. Resolution is really first-rate in this shot, with very fine details visible throughout the image. The individual strands of the model's hair are distinct, and her face reveals more fine detail than in the wider Outdoor Portrait. Additionally, the subtle surface textures of the house siding are very sharp. Noise remains low in the shadow areas, and is faintly present in the siding. Our main shot was taken with no exposure adjustment at all. The table below shows the results of a range of exposure settings from zero to +1.0 EV. Exposure Compensation Settings:
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Indoor Portrait, Flash: (741 k) The A20's built-in flash does a nice job illuminating the subject while producing a reasonably bright exposure. In all of our test shots, the A20 produced a strong orange cast in response to the bright incandescent room lighting (a common problem with digicams). We shot our first series of images with the flash in the normal shooting mode, adjusting the exposure compensation accordingly. This first series produced a somewhat dark background behind the subject, with a slight magenta tint in the orangish color cast. The model is fairly well lit, with good color. We did notice an orangish cast on the white shirt, resulting from the room lighting. We achieved the best exposure in this series with a +1.0 EV (722 k) exposure adjustment, which we chose for our main selection for this test. For our second series, we shot with the flash in the Slow Synchro mode, which combines the flash with a slower shutter speed. Because more ambient light is allowed into the image, the overall exposure is much brighter, and the orange cast is emphasized. Still, color appears reasonably accurate, with the exception of orange tints on the model's shirt, in her hair, and on her skin. In this series, we obtained the best exposure with a +1.0 EV (717 k) adjustment. The table below shows a range of flash exposures for both the normal and Slow Synchro flash modes.
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Indoor portrait, no flash: (729 k) 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, and the A20's white balance system acquitted itself very nicely. We shot samples of this image with the automatic (730 k) and incandescent (725 k) white balance settings, choosing the incandescent setting for our main series. The automatic setting resulted in a slightly warm image with a sepia color cast. The incandescent setting produced much more accurate results, though with a hint of warmth. Overall color balance and accuracy look good, with the slightly warm cast resulting in a yellowish tint in the white wall background and in the model's shirt. (Actually, we prefer at least a little warmth in this shot, to suggest the incandescent room lighting: The amount of color left in the A20's shots strikes us as just exactly right.) The blue flowers of the bouquet show faint purple tints at the edges of the petals, though the remaining flowers appear nearly accurate. (The red flower is very bright, enough that it begins to blur some details, but still looks good color-wise.) The skin tones are a bit orange, but are good overall. Resolution is high, with plenty of fine detail throughout the image. Details are also nice and sharp. Noise is moderately low, mainly noticeable in the darker shadow areas. Overall, another really excellent performance! We chose an exposure adjustment of +1.0 EV for our main image, as anything beyond that overexposed the highlight areas. The table below shows a range of exposures from zero to +1.7 EV. Exposure Compensation Settings:
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House shot: (1397 k) We shot samples of this image with the daylight (260 k) and automatic (262 k) white balance settings, which both produced nice images. The daylight setting resulted in a slightly warm image, though color still looked pretty good. We found the most accurate white value with the automatic setting, although the overall color is just slightly cool (very slightly). Overall though, the color is very nice, with good saturation levels. Resolution is quite high, with fine details distinguishable in the bricks and shrubbery, as well as in the tree limbs above the roof. Details are also fairly sharp, even in the more organic details of the trees in front of the house. (The rounded shapes of the leaves are often difficult for digicams to reproduce clearly, making them appear somewhat blurry.) The roof shingles show very low noise, as do the shadow areas. In-camera sharpening is barely noticeable, as we picked up only about a half of a pixel of a halo along the light and dark edges of the roof trim. Another really excellent result! The table below shows our standard range of resolution and quality settings. Resolution/Quality series
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Far-Field Test (1391 k) 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. We shot this image with the automatic white balance setting, which produced a very nice color balance, without any strong color casts. Colors are bright and vibrant, with good saturation and accuracy, although the greens are just a little intense (even for springtime in Atlanta). The overall appearance of the image is very nice though, and the color quite appealing. This shot is a strong test of detail, given the practically infinite range of fine detail in a natural scene like this, viewed from a distance. Resolution looks very high, with excellent detail in the tree branches, bricks, and house front. Overall sharpness looks great as well, with crisp distinct details even in the trees and shrubbery, and no hint of the corner softness we're accustomed to seeing in digicam lenses. We also judge a camera's dynamic range in this shot, comparing how well the camera holds detail in both the shadow and highlight areas. The A20 captures a fair amount of detail in the bright, white bay window, fooled just a little by the bright paint. The stark brightness of the bay window causes the area to glow a little (slight lens flare), but the A20 still manages to pick up fairly good detail here. The shadow area under the porch also shows a nice level of detail, as the brick pattern and porch light are distinguishable. The reflections in the panes of glass above the doorway are also commendable, with crisp outlines. Noise is moderately low in the roof shingles and shadow areas. A nice job overall. The table below shows our standard resolution and quality series.
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Lens Zoom Range We've received a number of requests from readers to take shots showing the lens focal length range of those cameras with zoom lenses. Thus, we're happy to present you here with the following series of shots, showing the field of view with the lens at full wide angle, at full 3x telephoto, and at full telephoto with 2.5x digital telephoto enabled. The A20's wide angle setting captures a very wide field of view, with only a hint of barrel distortion along the curb of the street. Resolution is high, with a lot of fine detail even in the deepest areas of the image. The 3x telephoto does a very nice job of increasing resolution and detail as it zooms into the image, increasing the amount of visible detail in the bright bay window area. The shrubbery and grasses in front of the house also increase in sharpness. Though resolution softens somewhat with the 2.5x digital enlargement, the overall image still looks pretty good. Exposure darkens slightly, and we see a number of JPEG artifacts in the glass window panes, but noise remains at a moderately low level.
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Musicians Poster (1122 k) For this test, we shot with the automatic (1128 k) and daylight (1122 k) white balance settings, this time choosing the daylight setting as the most accurate. The large amount of blue in the image often tricks digicams, but the A20's white balance system performed well. The automatic setting resulted in a slightly cool image, with very pale skin tones on the models. The daylight setting produced warmer results, with more accurate skin tones. Though the daylight setting causes the blue background to show some purplish/reddish tints (particularly at the top of the frame), we felt that the skin tones were more accurate and natural. The blue of the Oriental model's robe looks nearly accurate, with good saturation (this is often a difficult blue for digicams to reproduce correctly). Resolution is high, with practically all the detail in the bird's wings and silver threads of the blue robe visible. The color gradations on the bird wings also look nice, with an even gradient. We also noticed clear, sharp details in the beaded necklaces, flower garland, and violin strings (with just a hint of a moire pattern in the strings). Noise is moderately low, though slightly higher in the blue background (some noise could actually be the film grain in the poster itself). A very nice job. |
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Macro Shot (976 k) The A20 is a little limited in the macro category, capturing a larger than average minimum area of 6.41 x 4.81 inches (162.87 x 122.15 millimeters). However, color, detail and resolution all look good, with great detail visible in the coins as well as on the brooch. There's a faint moire pattern in the background surrounding Washington's portrait, probably from the fine pattern of the engraving on the bill. We also noticed a little barrel distortion from the lens' wide angle setting. The A20's built-in flash (961 k) does a great job of throttling down for the macro area, maintaining good color and increased clarity. Flash coverage is a little uneven, with a large hot spot in the center of the image, and falloff along the edges and in the corners. |
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"Davebox" Test Target (698 k) Have we said it before? This is great color! - We shot samples of this target using the automatic (698 k) and daylight (704 k) white balance settings, which both produced good results. The daylight setting resulted in a slightly warm image, with a yellowish/orangish cast to the white color block and resolution target. The automatic setting produced a more accurate white value, though it was slightly cool. Despite the cool cast, we felt that the automatic setting was the most accurate overall. The large color blocks look about right, though a little weak in saturation (with the exception of the blue blocks). The large magenta and red blocks have a bluish tint as well. The A20 adeptly distinguishes the subtle difference between the red and magenta color blocks on the middle, horizontal color chart (which is a common problem area for many digicams), though the black separator line has a reddish tint and the red block appears orangish. Exposure is a little bright, as the subtle tonal variations of the Q60 chart are visible all the way up to the "B" range, though only faintly (this is another common problem area for digicams). The tonal gradations of the smaller, vertical gray scales look nice, though the two darkest blocks on both scales blend together slightly. The shadow area of the charcoal briquettes shows excellent detail, with a moderately low noise level. We also noticed good detail in the highlights of the white gauze area. Resolution is high throughout the image, with fairly sharp details in the mini-resolution target. An excellent performance overall. |
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Low-Light Tests The A20 had a little trouble in the low-light category, as we were only able to obtain a reasonably bright image at the eight foot-candle light level (0.88 lux). Images were relatively bright and still usable as low as one foot-candle (11 lux) though, but became progressively darker from there. (We'd rate the minimum usable light level for the A20 as about 1 foot-candle.) The target is still visible at the 1/16 foot-candle (0.67 lux) light level, though the image is very dim. Noise is very low in all of the images, which is very commendable. To put the A20's low-light performance into perspective, an average city night scene under modern street lighting corresponds to a light level of about one foot-candle, meaning most night exposures will require use of the A20's built-in flash. The table below shows the best exposure we were able to obtain for each of a range of illumination levels. Images in this table (like all of our sample photos) are untouched, exactly as they came from the camera.
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Flash Range Test Canon rates the A20's flash as effective from 2.5 to 13.8 feet (0.76 to 4.2 meters) at wide angle, and from 2.5 to 8.2 feet (26 to 76 centimeters) at telephoto. In our testing, we found the A20's flash brightest at the eight foot distance from the target, leading us to agree with Canon's 8.2 foot rating with the lens at telephoto. The flash remained reasonably bright as far as 10 feet from the target, though the dimmer intensity produced a warm color cast. Flash power continued to decrease in intensity all the way out to 15 feet, but was still somewhat effective. Below is our flash range series, with distances from eight to 15 feet from the target.
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ISO-12233 (WG-18) Resolution Test (789 k) The PowerShot A20 did quite well in our resolution target test, producing clean detail out to 600 lines per picture height in the horizontal direction, and to 550 lines per picture height vertically. Strong detail was visible all the way out to 800 lines vertically and horizontally, with surprisingly low levels of artifacts at all target frequencies. Corner sharpness and chromatic aberration are both excellent, with virtually none of either evident. Optical distortion on the A20 is fairly low at the wide angle end, where we measured a 0.57 percent barrel distortion. The telephoto end fared even better, as we couldn't even find one pixel of pincushion distortion. (We actually noticed about a half-pixel of barrel distortion, essentially unmeasurable.) This is a very high quality lens, better than those on the majority of digicams we've tested.) Resolution Series, Wide Angle
Resolution Series, Telephoto
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Viewfinder Accuracy/Flash Uniformity We found the A20's optical viewfinder to be a fairly tight, showing approximately 78.08 percent of the final image area at wide angle (724 k), and about 79.0 percent at telephoto (738 k) (at the 1,600 x 1,200-pixel resolution size). We also noticed that images framed with the optical viewfinder were slanted toward the lower left corner, indicating a slightly shifted CCD. (The optical viewfinder is one of the few things we found to gripe about on the A20.) The LCD monitor was much more accurate, showing approximately 99.58 percent of the final image area at wide angle (695 k) and about 98.92 percent at telephoto (723 k) (also at the 1,600 x 1,200-pixel resolution size). Since we generally like to see LCD monitors as close to 100 percent accuracy as possible, the A20 performs very nicely in this regard. Flash distribution is fairly even at the telephoto setting, with a small hot spot/reflection in the center of the target. At wide angle, flash distribution is more uneven, with falloff around the edges and in the corners of the frame.
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