Canon A710 IS Optics
With a 35mm equivalent zoom range from 35 to 210mm equivalent focal lengths, the Canon PowerShot A710's 6x zoom lens reaches out quite a bit further than the 3-4x zooms more common on consumer point & shoot digital cameras. But more cameras are appearing with image-stabilized optics and long zooms (10x and 12x). Clearly there's room for a little longer focal length in an image stabilized digicam.
When it came to optical quality, our test results with the Canon A710 were a very pleasant surprise. It showed average amounts of barrel and pincushion distortion (not bad for a long-ratio zoom lens), but much better than average corner sharpness and chromatic aberration than we normally find in consumer cameras. Overall, the Canon A710 does very well in the optics department, the one fly in the ointment being an optical viewfinder that's excessively tight, showing only about 77% of the final frame area. Happily though, the LCD monitor is essentially 100% accurate.
A generous 6x optical zoom range, with good performance.
4x Digital Zoom
The Canon A710 zooms over the equivalent of a 35-210mm range, fairly unusual for its class (where 3x zoom predominate). Optical quality looks pretty good across the zoom range. See below for more detail. The 4x digital zoom takes it out to 24x total with the loss of quality that digital zoom creates.
A small macro area with good detail and high resolution. Flash does not throttle down well at this range, so plan on using external flash for macro shots.
|Standard Macro||Macro with Flash|
The PowerShot's macro setting performs well, capturing a small minimum area of 0.86 x 0.65 inches (21.9 x 16.4 millimeters). Detail is strong and resolution high, with some significant softening in the corners, along with chromatic aberration. (Most cameras have some softening in the corners in macro mode.) Note, however, that Macro focuses only at the wide angle end of the zoom range, requiring you to move the lens very close to the subject and consequently blocking much of the available light. The flash, not surprisingly, doesn't throttle down well, so plan on using external lighting for your closest macro shots with the A710.
Moderate barrel distortion.
This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide angle) or inward (like a pincushion -- usually at telephoto). The A710's 0.56% barrel distortion at wide angle is very low among the cameras I've tested. At the telephoto end, the A710's 0.20% pincushion distortion is about average.
|Barrel distortion at 35mm is 0.56%|
|Pincushion distortion at 210mm is 0.20%|
Quite low, small effect on images at edges.
|Wide: low, top left @ 200%||Wide: low, top right @ 200%|
|Tele: quite low, top left @200%||Tele: quite low, top right @200%|
The Canon A710 showed much lower chromatic aberration than we're accustomed to seeing in cameras of its class. Small amounts of CA were visible in the corners at wide angle focal lengths, with even smaller amounts present at the telephoto end of the lens' range; though it extends fairly broadly at wide angle, the color of the CA is not bright or very noticable.
Very slight softening in the corners of the frame, much less than average.
|Wide: slightly soft
in the upper left corner.
|Wide: sharper at center.|
|Tele: slightly soft
in the lower right corner.
|Tele: sharp at center.|
The Canon A710 showed only a slight loss of sharpness in the corners of the frame, quite a bit less than is average among cameras of its class. The center of the frame was slightly sharper at wide angle than telephoto, but the difference between the two was minor indeed. This is a good illustration of the advantage a slightly larger camera has over a slim, pocket digital camera: fewer optical compromises are necessary.
Optical viewfinder is very tight and skewed to the upper right. Very good accuracy from the LCD monitor.
|Wide Angle, optical viewfinder||Telephoto, optical viewfinder|
|Wide Angle, LCD monitor||Telephoto, LCD monitor|
The A710's optical viewfinder was quite tight, showing only about 77% frame accuracy at both wide angle and telephoto lens settings. However, the LCD monitor showed close to 100 percent frame accuracy.