Canon A700 Exposure

Exposure and White Balance

Indoors, incandescent lighting
Slight warm cast with Auto and Incandescent white balance and cool with Manual white balance. Exposure compensation was required.

Color balance indoors under Auto white balance was warm and under Incandescent lighting a bit cool. The PowerShot required a +1.0 EV exposure compensation boost to get a good exposure with Auto white balance and +0.7 EV with Incandescent. Overall color well-balanced and hue accurate. Our test lighting for this shot is a mixture of 60 and 100 watt household incandescent bulb, a pretty yellow light source, but a very common one in typical home settings here in the U.S.

Outdoors, daylight
Good color balance, very bright colors. Better than average exposure accuracy.

Outdoor shots generally showed accurate exposure with slightly blown out highlights. Shadow detail also tended to fall apart, but nothing that would raise an alarm for a consumer digicam. Sunlit shots showed high contrast and moderate oversaturation while overcast scenes managed a more accurate portrayal. Exposure accuracy overall was better than average, the camera typically requiring less exposure compensation than we're accustomed to seeing with consumer digicams.

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

Resolution
High resolution, 1,300 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,300 lines per picture height, with extinction at around 1,600. You could perhaps argue for 1,400 lines of resolution, but we felt that the level of artifacts there was too high to justify a rating at that level. (The camera did produce some artifacts even at lower line frequencies though, visible both below and in the full-sized res target shots.) 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. Beware that while you might be able to make out what looks like distinct lines at numbers higher than those we've mentioned here, the camera is just doing its best to continue interpreting the lines. If you zoom in and follow them from the wider portions, you'll see the lines converge and reappear several times, so the lines you see at 1,600 and higher are really only artifacts generated by the camera's imaging system.

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

Sharpness & Detail
Fairly sharp images, only minor blurring of detail from noise suppression.

The PowerShot's images are reasonably sharp, with only slight over-sharpening or edge enhancement on the camera's part. (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. On the A700, noise suppression at shutter speeds above 1.3 seconds is fairly modest in its impact, with relatively little loss of subtle detail.

ISO & Noise Performance
Moderate noise at the normal sensitivity settings, very high noise that blurs detail at the higher settings.

The PowerShot A700's sensitivity ranges from ISO 80 to 800 equivalents. Up to ISO 200, the PowerShot produced very little noise, with only slightly blurred detail in the dark areas. At ISO 400 and especially at 800, the noise level and the amount of blurring that results increased noticeably. Overall though, the Canon A700's noise levels are lower than average for its class.

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 A700 had a little trouble with the deliberately harsh lighting in the test above, producing somewhat high contrast with lost highlight detail and deep shadows. The A700 required a bit less exposure compensation than some competing models, as this shot usually calls for about +1.0 EV of adjustment. (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 A700 did very well in our low light tests, producing bright images at the lowest light levels at ISO 200 and above. At ISO 80 and 100, images were bright down to the 1/8 foot-candle level, about 1/8 as bright as average city street lighting at night. The one limitation though, is that you have to resort to Shutter Priority or Manual exposure mode to get exposure times longer than 1 second. As seen by the type in even the darkest images, the auto focus system worked well, relying on its AF assist lamp to find focus at the very darkest levels, but was also able to focus down at a bit less than 1/4 foot-candle without resorting to the AF assist. Given that typical city street-lighting at night is about one foot-candle (the brightest level shown in the test above), the Canon A700 should have no trouble handling the after-dark photography needs of most consumers.

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.