Canon A550 Exposure

Saturation & Hue Accuracy
Overall very good color, with good hue accuracy. Some slight oversaturation in reds and blues, but still quite good results.

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. The Canon PowerShot A550 does oversaturate the strong red tones, and some blues a little, but the results are still quite pleasing.

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. Here, the A550 did render skin tones slightly on the warm side in most cases, but many consumers find slightly warm skin tones more pleasing than cooler ones.

The other important part of color rendition is hue accuracy. Hue is "what color" the color is. Here, the A550 again performed well, though it pushed cyan tones toward blue (a common occurrence among Canon digital cameras), and some reds toward orange. Still, very good results.

Exposure and White Balance

Indoors, incandescent lighting
Good color with the Manual white balance setting, though a hint warm. Average positive exposure compensation required.

Color balance indoors under incandescent lighting was pretty warm with the Auto white balance setting, though the Manual and Incandescent options produced much more accurate results. Because the Incandescent setting had a hint of a cool, magenta cast, I chose the slightly warmer (and more natural-looking) Manual setting. The Canon A550 required an average amount of positive exposure compensation here, at +1.0 EV. Despite the slight warm cast, overall color with the Manual white balance setting is excellent, without strong purple tints in the blue flowers. (Many digital cameras reproduce these flowers with a dark, purplish tint, so the A550 performed very well 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.

Outdoors, daylight
Good color and exposure, though slightly high contrast with the default setting.

Outdoors, the Canon PowerShot A550 performed pretty well, with only slight overexposure in the outdoor wide shot. The camera required less than the average amount of positive exposure compensation on the portrait. Default contrast is on the high side, though the camera's contrast adjustment did a pretty good job of taming the exposure without strongly affecting the color. The A550 captured good color outdoors, without too strong of a warm cast. Overall, pretty good results here.

See full set of test images with explanations
See thumbnails of all test and gallery images

Resolution
High resolution, 1,400 ~ 1,600 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,600 lines per picture height horizontally, though really only to about 1,400 lines vertically. Extinction didn't really occur horizontally, though lines began to merge around 1,900-2,000 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.

See full set of test images with explanations
See thumbnails of all test and gallery images

Sharpness & Detail
Sharp images overall, though slight edge-enhancement on high-contrast subjects. Moderate noise suppression limits detail in the shadows.

The Canon PowerShot A550 captures sharp images with good detail definition, though some edge 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.)

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. The crop above right shows this, as the darker areas of Marti's hair show limited detail.

ISO & Noise Performance
Low to moderate noise at the normal sensitivity settings, though a big jump in noise with strong blurring at the higher settings.

Noise levels are low to moderate at the Canon A550's lower sensitivity settings, with much higher noise at ISO 400 and 800 (as you'd expect). Noise pixels are bright at both settings, which throws off the color balance a bit, and the grain pattern eliminates some of the finer details. Still, it's not bad, retaining a surprising amount of detail.

Extremes: Sunlit and low light tests
High resolution with strong overall detail, but slightly high contrast and limited shadow detail. Excellent low-light performance, capable of capturing bright images in near darkness.

Sunlight:
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.)

The Canon PowerShot A550 produced fairly high contrast with deep shadows under the harsh lighting of the test above. However, the camera's contrast adjustment handled this problem fairly well, without strongly affecting color balance or tonal gradations. Detail is limited in the shadow areas, with some noise suppression visible. Though some areas look a little dark at +0.7 EV, I preferred it to the image at +1.0 EV, which had too many blown highlights for my preference. (In "real life" though, be sure to use fill flash in situations like the one shown above; it's better to shoot in the shade when possible.)

Low light:
The Canon PowerShot A550 captured bright images down to the 1/16 foot-candle light level (about 1/16 as bright as average city street lighting at night). At ISO 80, the image at this lowest light level is a bit dim, but really still usable. The camera's autofocus system was able to focus on the subject down to just below the 1/4 foot-candle light level without the AF assist light, so you'll need to make sure it's enabled for darker conditions. Do keep in mind though, that the very long shutter times necessary here absolutely demand the use of a tripod or other camera support to get sharp photos. (A useful trick 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.)

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
Slightly dim exposures at the default exposure setting; the camera required less-than-average exposure compensation for flash exposures. Typical range.

Flash coverage was uneven at wide angle; and though it was more even at telephoto, the intensity decreased. Indoors, under incandescent background lighting, the Canon A550's flash underexposed our subject a little at its default setting, requiring a +0.7 EV exposure compensation adjustment to get bright results. The camera's Slow-Sync flash mode required the same amount of positive compensation, though overall coverage is more even. In both exposures, the background incandescent lighting resulted in a noticeable orange cast.

At wide angle, shots at ISO 100 are bright out to a distance of about 11 feet, decreasing in brightness from that point on. At full telephoto and ISO 100, even the 6-foot shot is a little dim, and the images darken from there. A typical result for compact models.

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. In the shots above, the A550 seems to perform exactly as Canon says it will, producing good exposures at the rated distances with its ISO set to Auto.

Print Quality
Good print quality, great color, good 13x19 inch prints. ISO 400 images are soft but usable at 11x14, ISO 800 shots are still good at 8x10.

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 i9900 studio printer, and on the Canon iP5200 here in the office. (See the Canon i9900 review for details on that model.)

The Canon PowerShot A550 had enough resolution to make good looking 13x19 inch prints. ISO 400 images still look good at 11x14, which is quite a surprise. And ISO 800 images still look good at 11x14 when shot in daylight balanced lighting, but indoor incandescent shots are better kept to 8x10. An impressive performance from a sub-$200 camera.