White Balance
The A620 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 (as confirmed by our studio tests). Indoors it's a bit more hit and miss, as we've seen with most Canon PowerShots, fluorescent lighting doesn't cause much of a problem, whereas incandescent (tungsten) lighting causes a fairly strong orange color cast. Best to stick to the preset (or one-push custom WB) or the tungsten preset if you want more neutral colors.
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Outdoor - Auto WB |
Fluorescent - Auto WB Red 0.2%, Blue 0.1% Excellent |
Incandescent - Auto WB Red 9.5%, Blue -15.3% Poor |
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Flash Performance
The A620's built-in flash has a quoted working range of 0.45m - 4.2m (1.5 - 11.5 ft) at the wide end of the zoom and 0.45m - 2.5m (1.5 - 7.2 ft) at the tele end - more or less the same as the A95. It also works down to about 25cm (11.8 inches) in macro mode (in all cases assuming the ISO is set to auto). In our real-world tests the flash did a perfectly good job within its effective range, exposing perfectly in a wide range of situations and with virtually no color cast. Recycle time - though still not class-leading - is a significant improvement over the A95, and rarely gives cause for complaint.
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| Skin tone Excellent color, Slight underexposure |
Color chart No color cast, very slight underexposure |
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Macro Focus
As is common to most compact digital cameras the A620's macro mode is most effective at the wide end of the zoom, where you can get as close as 1cm - very impressive. At the long end of the zoom the performance is less impressive - 25cm subject distance - but still pretty useful. 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.
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| Wide macro - 21 x 16 mm coverage 140 px/mm (3559 px/in) Distortion: Average Corner softness: Low to average Equiv. focal length: 35 mm |
Tele macro - 76 x 57 mm coverage 40 px/mm (1016 px/in) Distortion: Very low Corner softness: Low to average Equiv. focal length: 140 mm |
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Barrel and Pincushion Distortion
Barrel distortion is - at 1.1% - fairly low for a camera in this class, and certainly doesn't mar real world scenic shots. There is a tiny (0.2%) amount of measurable pincushion distortion at the telephoto end of the zoom.
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| Barrel distortion - 1.1% at Wide angle Equiv. focal length: 35 mm |
Pincushion distortion - 0.2% at Telephoto Equiv. focal length: 140 mm |
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Specific Image Quality Issues
No real complaints here - the A620 produces clean, detailed results in a wide variety of shooting situations. The images are a touch on the soft side when viewed at 100% on-screen, but they respond well to a little unsharp masking, and I'd rather that than images that are over-processed (especially over-sharpened). Colors are natural (less over-saturated than the A95), and white balance generally very accurate (unless you're shooting under tungsten lighting). We're not talking groundbreaking image quality here - there's still some muddying of low contrast detail such as foliage, but the pictures are on a par with all the other 7MP cameras in this class, and - given the specification on offer and the keen pricing - I don't think many users will find much to grumble about.
The good news is that the purple fringing that plagued the A95 has been all but eliminated, and focus accuracy is significantly better (only one or two shots out of 500 had missed focus).
Color fringing
We found very little evidence of purple fringing in any of our real-world shots - where there is some it is only in overexposed areas, and is so soft as to be unnoticeable at normal print sizes. This is a real improvement over the A95 (and many of the SD/IXUS models too).
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| 100% crop | 35 mm equiv., F3.5 |
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Highlight clipping
As is common with small sensor, high pixel count cameras, the A620 struggles to capture the full range of brightnesses in scenes with a large dynamic range (high contrast, very bright days). This sensor has shown itself to be capable of capturing a fairly wide dynamic range with the right processing, and the A620's problem seems to be a combination of slight overexposure of contrasty scenes, and a fairly steep tone curve, which can lead to quite harshly clipped highlights. We found the problem could be minimized by careful use of AE compensation when the metering got it wrong, but this is hardly a completely acceptable situation, as clipped highlights can be difficult to spot on a small LCD screen. To be fair, the problem wasn't widespread, but was prevalent enough to merit mention here. Below is a classic example - the large tree has fooled the meter into overexposing by a stop or so, meaning most of the highlight detail has been lost forever.
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| 100% crop | 35 mm equiv., F3.5 |
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