Overall Image Quality
The overall feeling is "what a great little camera", the A20, just like the IXUS 300, does the business, image quality is excellent for an "entry level" digital camera, sharpness is good as are colours which are nice and strong without being over saturated (indeed for some slightly odd reason the A20's colour seems a little better than the IXUS 300). As with the IXUS 300 the A20 does have a tendency to meter about 0.3 EV over so a compensation of -0.3 EV when shooting outdoors in good light is recommended.Looking more closely at the images (especially around an item of detail on an otherwise flat surface) reveals Canon's noise reduction system has been at work, cleaning away any sign of noise from flat surfaces / gradients.
Maintaining shadow detail
|Original image, good for printing, shadow detail maintained||Contrast adjusted image, perfect for the monitor, less ideal for printing|
Again, as we noted in the IXUS 300 review the A20 does attempt to maintain as much shadow detail as possible by pushing the dark end of the grayscale up to at about 10%, this means that no dark detail gets clipped by over enthusiastic contrast algorithms, this leads to a neutrally balanced and fairly "flat" image (which may not be to everyones taste but is preferable).
This balance of image works perfectly for printing, indeed some of the thought process behind it may be to do with Canon's new direct-connect printers, but mostly I think it's just to maintain detail were it would normally be clipped. Obviously this means that if you want your images to have real contrast (black is black) you'll need to do a little level correction on some of them (Photoshop; Image > Adjust > Auto Contrast; will do this fairly well).
Purple Fringing (Chromatic Aberrations)
Once more good news from Canon, the PowerShot A20 exhibits almost no visible chromatic aberrations, it does, as with the IXUS 300, suffer from a little blooming (the overflow of charge from saturated pixels) which you can see below, but this shot taken with a camera with chromatic aberrations would have had a large purple fringes along the edge of this detail.
Whether Canon are doing this through post-processing or its down to the lens / sensor design is inconsequential we have to give some Kudos to Canon for virtually eliminating one of our biggest complaints.
|Visible chromatic aberrations in an "every day shot"|
|Our now standard chromatic aberration test shot|
Barrel and Pincushion Distortion
Vritually no pincushion distortion at full tele, another excellent achievement from such a small lens. There is however visible barrel distortion at full wide angle, we measured it as about 1.1%.
|Barrel Distortion, 1.1% @ Wide Angle||Pincushion Distortion, ~0% @ Full Tele|
The A20 has the same excellent white balance system we were so pleased with on the IXUS 300. Canon appear to have solved the problem of white balance presets which don't quite work (nasty hue shifts and such), the sunny, indoor and fluorescent presets work well and should get you out of trouble even in odd lighting conditions. The Auto white balance only seemed to work well in natural light.
|Outdoors, Auto||Outdoors, Sunny||Outdoors, Cloudy|
|Incandescent, Auto||Incandescent, Indoor|
|Fluorescent, Auto||Fluorescent, Fluorescent|