Canon A710 IS Optics

Zoom
A generous 6x optical zoom range, with good performance.

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.

Macro
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.

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.

Distortion
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.

Chromatic aberration
Quite low, small effect on images at edges.

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.

Corner Sharpness
Very slight softening in the corners of the frame, much less than average.

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.

Coverage
Optical viewfinder is very tight and skewed to the upper right. Very good accuracy from the 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.