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Photographic tests

White balance

The A710 IS has six white balance presets (daylight, cloudy, tungsten, fluorescent, fluorescent H and Underwater) in addition to the default auto white balance. There is also a 'custom' white balance setting, which allows you to point the camera at a white or gray object and set the white balance manually. The custom white balance setting is remembered even if you turn the camera off. In normal outdoor shooting the auto white balance works perfectly. Indoors it's a bit more hit and miss, as we've seen with most Canon PowerShots incandescent (tungsten) lighting causes a fairly strong orange color cast (though switching to manual gives a perfectly neutral result).

Auto White Balance Fluo Preset Auto White Balance Incandescent preset
Fluorescent light - Auto white balance average,
Preset white balance average
Incandescent light - Auto white balance poor,
Preset white balance good

Flash

The A710's built-in flash has a quoted working range of 0.55m - 3.5m (1.8 - 11 ft) at the wide end of the zoom and 0.55m - 2.5m (1.8 - 8.2 ft) at the tele end, which is around average for a camera of this type, and perfectly adequate for the kind of social snaps you're likely to be using it for. Exposure is excellent even down to about 12 inches in macro mode and our only complaint is that the recycle time can stretch to 5 seconds or more if you're shooting at full power and don't have freshly charged batteries. The red-eye reduction system (used here) works fairly well.

Click here for flash test chart

Skin tone - Excellent color and exposure.

Macro

As is common to most compact digital cameras the A710's macro mode is most effective at the wide end of the zoom, where you can get as close as 1cm, capturing an area just under an inch across (22mm to be exact) - very impressive. The macro mode is only usable in the first half of the zoom range (up to about the 100mm equiv. point), but even at the long end of the zoom you can focus down to about 55cm, capturing an area just over 10cm across. There is inevitably some distortion when shooting very close up at the wide end, but it is not too strong, and certainly less so than many of its competitors. In both these shots you can see a little mild Chromatic Aberration (CA).

Movie mode

As is now the norm on cameras of this type the A710 IS offers a maximum movie size of 640x480 pixels - enough to fill most television screens at 30 frames per second. It also offers options to shoot at smaller sizes and lower frame rates. There's a 'high frame rate' option that shoots 320x240-pixel movies at 60fps.

Overall quality is very good - as we've come to expect from Canon, with movies very smooth and showing few compression artifacts, though inevitably the quality drops a little if you use the digital zoom. The downside of such high quality is that the AVI files are large - at the best quality setting (640x480 / 30fps) you're burning around 1.7MB every second, so if you intend to shoot a lot of movies you're going to need to invest in some big, fast SD cards. As with most PowerShots there is a 1.0GB limit to each movie clip.

One of the big improvements over the A700 is the image stabilization system, which means no more jerky movies.

Sample movie: 640 x 480 pixels @ 30 fps
File size: 13.6 MB, 7.1 secs

Click on the thumbnail to view the movie (caution: large file!)

Resolution

As we'd expect resolution is slightly better than the A700, and is around average for a 7MP camera. They're not the cleanest results, with visible moiré at the highest frequencies, but they are otherwise artefect-free and pretty detailed (bit soft, but easily sharpened). Impressive stuff for a budget camera with such a wide zoom range.

Crops

Click here for the full resolution test chart

Horizontal LPH

Absolute resolution 1500 LPH
Extinction resolution 1800 LPH

 

Vertical LPH

Absolute resolution 1550 LPH
Extinction resolution 1950 LPH *

*moiré visible

Distortion and other image quality issues

The A710 IS exhibits moderate distortion at the wide end of the zoom - 1.2% barrel distortion (click here for test chart), but it's nothing to worry about on a camera of this type. There is a small (0.3%) amount of measurable pincushion distortion at the telephoto end of the zoom (click here for test chart).

General comments

Pretty much everything we said about the A700 holds true for the A710 IS. No real complaints here - once you've learned it's metering foibles the A710 produces clean, sharp, detailed results in a wide variety of shooting situations. Colors are natural and white balance generally very accurate (unless you're shooting under artificial lighting), although there is a slight tendency to over saturate bright primary colors. We're not talking groundbreaking image quality here - there is very slight corner softness at the widest aperture and the images are very slightly soft and over-sharpened, but given the pricing and specification there is more to like than to complain about.

The A710 IS suffers from exactly the same problem as the A700 in bright, contrasty scenes; highlight clipping - usually caused by mild overexposure compounded by the high default contrast. You can - with careful exposure and use of the low contrast option in-camera - get pretty decent dynamic range out of the A710 IS if you know what you're doing.

Purple fringing is thankfully rare (though you will still get some in extreme circumstances) and we found little if any of the chromatic aberration seen in a couple of our studio/lab tests when examining 'real world' images (it is very mild and only seems to occur at the wide end of the zoom). The A700's biggest problem - camera shake - has been pretty much solved by the A710's image stabilization system.

Noise

With tiny, high pixel count chips noise is always going to be an issue, and to a large degree this is more a test of the effectiveness (both measurable and visible) of a camera's noise reduction system. Designers have to balance the desire to produce smooth, clean results with the need to retain as much detail as possible (if you blur away the noise, you blur away image detail too).

The A710 has broadly the same measurable - and visible - levels of noise as the 6MP A700 that preceded it (it is in fact slightly better, but not by a wide margin). Chroma noise starts to appear in the mid-tones at ISO 200 and ISO 400 looks quite noisy, but, crucially, has plenty of detail (see below). Compared to earlier Canon cameras using the larger 1/1.8" 7MP sensor the A710 IS puts up a good fight (measurably and visibly less 'grainy') but I suspect this is more a case of more effective NR than any inherent quality of the sensor itself.

ISO 80 ISO 100 ISO 200 ISO 400 ISO 800
100% Crops

Noise graph

Indicated ISO sensitivity is on the horizontal axis of this graph, standard deviation of luminosity is on the vertical axis.

Low contrast detail

What the crops and graph don't show is the effect of noise reduction on low contrast fine detail such as hair, fur or foliage. An inevitable side effect of noise removal is that this kind of detail is also blurred or smeared, resulting in a loss of 'texture'. In a new test the crops below show the effect of the noise reduction on such texture (fur) as you move up the ISO range.

100% Crops
ISO 80 ISO 100 ISO 200
 
ISO 400 ISO 800  

As we've seen with most recent PowerShots, Canon's fairly light-handed approach to noise reduction may produce slightly grainier results, but it does bear fruit in the retention of low contrast detail, even up to ISO 400, to a degree (many cameras have already smeared this type of low contrast detail by ISO 200).

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